Carrier Electric Heater 48EZN A User Manual

48EZ(N)---A  
Comfort t 13 SEER Single---Packaged HYBRID HEATr  
Dual Fuel System with Puron® (R---410A) Refrigerant  
Single and Three Phase  
2 --- 5 N o m i n a l To n s ( S i z e s 2 4 --- 6 0 )  
Installation Instructions  
NOTE: Read the entire instruction manual before starting the  
installation.  
NOTE: Installer: Make sure the Owner’s Manual and Service  
Instructions are left with the unit after installation.  
TABLE OF CONTENTS  
PAGE  
SAFETY CONSIDERATIONS . . . . . . . . . . . . . . . . . . . . . . . 1--2  
INTRODUCTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2  
RECEIVING AND INSTALLATION . . . . . . . . . . . . . . . . . 2--13  
Check Equipment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2  
Identify Unit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2  
Inspect Shipment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2  
Provide Unit Support . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2  
Roof Curb . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2  
Slab Mount . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2  
Field Fabricate Ductwork . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6  
Provide Clearances . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6  
Rig and Place Unit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6  
Connect Condensate Drain . . . . . . . . . . . . . . . . . . . . . . . . . . . 7  
Install Flue Hood . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7  
Install Gas Piping . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7  
Install Duct Connections . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9  
Configuring Units for Downflow (Vertical)  
A09034  
Fig. 1 -- Unit 48EZ--A  
Gas Input . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35  
Indoor Airflow . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35  
Check Defrost Thermostat . . . . . . . . . . . . . . . . . . . . . . . . . . . 35  
PuronR Items . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35  
TROUBLESHOOTING . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38  
START--UP CHECKLIST . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38  
Discharge . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9  
Install Electrical Connections . . . . . . . . . . . . . . . . . . . . . . . . 12  
High--Voltage Connections . . . . . . . . . . . . . . . . . . . . . . . . 12  
Special Procedures for 208--V Operation . . . . . . . . . . . . . . 12  
Control Voltage Connections . . . . . . . . . . . . . . . . . . . . . . . 13  
Balance Point Setting Thermidistat or Hybrid Heat  
SAFETY CONSIDERATIONS  
Installation and servicing of this equipment can be hazardous due  
to mechanical and electrical components. Only trained and  
qualified personnel should install, repair, or service this equipment.  
Thermostat . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13  
Transformer Protection . . . . . . . . . . . . . . . . . . . . . . . . . . . 13  
P R E -- S T A R T -- U P . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 3 -- 1 4  
START--UP . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14--17  
Check for Refrigerant Leaks . . . . . . . . . . . . . . . . . . . . . . . . . 14  
Unit Sequence of Operation . . . . . . . . . . . . . . . . . . . . . . . . . 14  
Start--Up Heating and Make Adjustments . . . . . . . . . . . . . . . 14  
Checking Heating Control . . . . . . . . . . . . . . . . . . . . . . . . . 14  
Check Gas Input . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15  
Adjust Gas Input . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15  
Check Burner Flame . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16  
Start--Up Cooling and Make Adjustments . . . . . . . . . . . . . . . 16  
Checking Cooling Control Operation . . . . . . . . . . . . . . . . 16  
Checking and Adjusting Refrigerant . . . . . . . . . . . . . . . . . 17  
Indoor Airflow and Airflow Adjustments . . . . . . . . . . . . . 17  
MAINTENANCE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32--38  
Air Filter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32  
Indoor Blower and Motor . . . . . . . . . . . . . . . . . . . . . . . . . . . 32  
Flue Gas Passageways . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33  
Limit Switch . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33  
Burner Ignition . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33  
Main Burners . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33  
Outdoor Coil, Indoor Coil, & Condensate Drain Pan . . . . . . 33  
Outdoor Fan . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34  
Electrical Controls and Wiring . . . . . . . . . . . . . . . . . . . . . . . 34  
Refrigerant Circuit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34  
Untrained personnel can perform basic maintenance functions such  
as cleaning and replacing air filters. All other operations must be  
performed by trained service personnel. When working on this  
equipment, observe precautions in the literature, on tags, and on  
labels attached to or shipped with the unit and other safety  
precautions that may apply.  
Follow all safety codes. Wear safety glasses, protective clothing,  
and work gloves. Have fire extinguisher available. Read these  
instructions thoroughly and follow all warnings or cautions  
included in literature and attached to the unit. Consult local  
building codes, the current editions of the National Fuel Gas Code  
(NFGC) NFPA 54/ANSI Z223.1, and the National Electrical Code  
(NEC) NFPA 70.  
In Canada refer to the current editions of the National Standards of  
Canada CAN/CSA--B149.1 and .2 Natural Gas and Propane  
Installation codes, and Canadian Electrical Code CSA C22.1.  
Recognize safety information. This is the safety--alert symbol  
.
When you see this symbol on the unit and in instructions or manu-  
als, be alert to the potential for personal injury. Understand these  
signal words: DANGER, WARNING, and CAUTION. These  
words are used with the safety--alert symbol. DANGER identifies  
the most serious hazards which will result in severe personal injury  
or death. WARNING signifies hazards which could result in per-  
sonal injury or death. CAUTION is used to identify unsafe practic-  
1
Download from Www.Somanuals.com. All Manuals Search And Download.  
A09450  
Fig. 2 -- 48EZ--A24--36 Unit Dimensions  
3
Download from Www.Somanuals.com. All Manuals Search And Download.  
A09451  
Fig. 3 -- 48EZ--A42--60 Unit Dimensions  
4
Download from Www.Somanuals.com. All Manuals Search And Download.  
B
HVAC unit  
basepan  
C
HVAC unit  
base rails  
Sealing  
Gasket  
Roofcurb  
H
F
A
Anchor screw  
Wood nailer*  
Roofcurb*  
Flashing field  
supplied  
Insulation  
(field supplied)  
Roofing material  
field supplied  
E
D
Cant strip  
field supplied  
SMALL CURB  
A09418  
*Provided with roofcurb  
A09090  
ROOF CURB DETAIL  
B
C
G
H
A
F
E
D
LARGE CURB  
A09415  
A09419  
CATALOG  
NUMBER  
CPRFCURB010A00  
CPRFCURB011A00  
CPRFCURB012A00  
CPRFCURB013A00  
A
B
C
D
E
F
G
H
UNIT SIZE  
Small  
IN. (mm)  
IN. (mm)*  
IN. (mm)  
IN. (mm)  
IN. (mm)  
IN. (mm)  
IN. (mm)  
IN. (mm)  
11 (279)  
14 (356)  
11 (279)  
14 (356)  
10 (254)  
32.4 (822)  
30.6 (778)  
47.8  
(1214)  
16 (406)  
2.7 (69)  
46.1 (1170)  
43.9  
(1116)  
Large  
14 (356)  
42.2 (1072)  
NOTES:  
1. Roof curb must be set up for unit being installed.  
2. Seal strip must be applied, as required, to unit being installed.  
3. Roof curb is made of 16--gauge steel.  
4. Attach ductwork to curb (flanges of duct rest on curb).  
5. Insulated panels: 1--in. (25.4 mm) thick fiberglass 1 lb. density.  
IMPORTANT: Do not install large base pan HYBRID HEAT units onto  
the small base pan (common curb). The center of gravity on a large base  
pan HYBRID HEAT unit could overhang the curb causing an unsafe  
condition. Before installing any large base pan unit onto the common  
curb, check the “Y” distance in the product literature dimensional drawing  
to ensure that “Y” is greater than 14 in. (356 mm). Do not install any large  
base pan unit onto the common curb with a “Y” dimension (center of  
gravity) less than 14 in. (356 mm).  
Fig. 4 -- Roof Curb Dimensions  
5
Download from Www.Somanuals.com. All Manuals Search And Download.  
CAUTION - NOTICE TO RIGGERS  
PRUDENCE - AVIS AUX MANIPULATEUR  
ACCESS PANELS MUST BE IN PLACE WHEN RIGGING.  
PANNEAUX D'ACCES DOIT ÊTRE EN PLACE POUR MANIPULATION.  
Use top skid as spreader bar. / Utiliser la palette du haut comme barre de répartition  
DUCTS  
MINIMUM HEIGHT: 36" (914.4 mm)  
HAUTEUR MINIMUM  
BANDE SCELLANT DOIT ÊTRE  
EN PLACE AVANT DE PLACER  
L'UNITÉ SUR LA BASE DE TOIT  
SEAL STRIP MUST BE IN  
PLACE BEFORE PLACING  
UNIT ON ROOF CURB  
UNIT HEIGHT  
HAUTEUR D'UNITÉ  
DETAIL A  
VOIR DÉTAIL A  
SEE DETAIL A  
VOIR DÉTAIL A  
50CY502286 2.0  
A09051  
RIGGING WEIGHTS (SMALL CABINET)  
RIGGING WEIGHTS (LARGE CABINET)  
42 48  
24  
30  
36  
60  
Unit  
Unit  
lb  
kg  
lb  
kg  
lb  
kg  
lb  
kg  
lb  
kg  
lb  
kg  
230  
Rigging  
Weight  
Rigging  
Weight  
359  
163  
373  
169  
379  
172  
461  
209  
482  
219  
507  
NOTE: See dimensional drawing for corner weights.  
Fig. 5 -- 48EZ--A Suggested Rigging  
Step 3 — Field Fabricate Ductwork  
Step 5 — Rig and Place Unit  
Secure all ducts to roof curb and building structure on vertical  
discharge units. Do not connect ductwork to unit. For horizontal  
applications, unit is provided with flanges on the horizontal  
openings. All ductwork should be secured to the flanges. Insulate  
and weatherproof all external ductwork, joints, and roof openings  
with counter flashing and mastic in accordance with applicable  
codes.  
If a plenum return is used on a vertical unit, the return should be  
ducted through the roof deck to comply with applicable fire codes.  
See unit rating plate for any required clearances around ductwork.  
Cabinet return--air static shall not exceed --.25 IN. W.C.  
!
WARNING  
PERSONAL INJURY OR PROPERTY DAMAGE  
HAZARD  
Failure to follow this warning could result in personal  
injury, death or property damage.  
When installing the unit on a rooftop, be sure the roof will  
support the additional weight.  
Rigging and handling of this equipment can be hazardous for  
many reasons due to the installation location (roofs, elevated  
structures, etc.).  
Step 4 — Provide Clearances  
The required minimum operating and service clearances are shown  
in Fig. 2 and 3.  
IMPORTANT: Do not restrict outdoor airflow. An air restriction  
at either the outdoor--air inlet or the fan discharge may be  
detrimental to compressor life.  
Only trained, qualified crane operators and ground support staff  
should handle and install this equipment.  
When working with this equipment, observe precautions in the  
literature, on tags, stickers, and labels attached to the equipment,  
and any other safety precautions that might apply.  
The condenser fan pulls air through the condenser coil and  
discharges it through the top grille. Be sure that the fan discharge  
does not recirculate to the condenser coil. Do not locate the unit in  
either a corner or under an overhead obstruction. The minimum  
clearance under a partial overhang (such as a normal house  
overhang) is 48--in. (1219 mm) above the unit top. The maximum  
horizontal extension of a partial overhang must not exceed 48--in.  
(1219 mm).  
Training for operators of the lifting equipment should include, but  
not be limited to, the following:  
1. Application of the lifter to the load, and adjustment of the  
lifts to adapt to various sizes or kinds of loads.  
2. Instruction in any special operation or precaution.  
3. Condition of the load as it relates to operation of the lifting  
kit, such as balance, temperature, etc.  
Do not place the unit where water, ice, or snow from an overhang  
or roof will damage or flood the unit. Do not install the unit on  
carpeting or other combustible materials. The unit may be installed  
on Class A, B, or C roof covering materials. Slab mounted units  
should be at least 4--in. (102 mm) above the highest expected water  
and runoff levels. Do not use unit if it has been under water.  
Follow all applicable safety codes. Wear safety shoes and work  
gloves.  
Inspection  
Prior to initial use, and at monthly intervals, all rigging shackles,  
clevis pins, and straps should be visually inspected for any  
damage, evidence of wear, structural deformation, or cracks.  
Particular attention should be paid to excessive wear at hoist  
6
Download from Www.Somanuals.com. All Manuals Search And Download.  
TRAP  
OUTLET  
hooking points and load support areas. Materials showing any kind  
of wear in these areas must not be used and should be discarded.  
1-in. (25 mm) min.  
!
WARNING  
2-in. (51 mm) min.  
UNIT FALLING HAZARD  
Failure to follow this warning could result in personal  
injury or death.  
Never stand beneath rigged units or lift over people.  
A09052  
Fig. 6 -- Condensate Trap  
!
WARNING  
Step 7 — Install Flue Hood  
The flue assembly is secured and shipped in the return air duct.  
Remove duct cover to locate the assembly (See Fig. 8).  
PROPERTY DAMAGE HAZARD  
Failure to follow this warning could result in personal  
injury/death or property damage.  
NOTE:  
Dedicated low NOx models MUST be installed in  
California Air Quality Management Districts where a Low NOx  
rule exists.  
When straps are taut, the clevis should be a minimum of 36  
in. (914 mm) above the unit top cover.  
These models meet the California maximum oxides of nitrogen  
(NOx) emissions requirements of 40 nanograms/joule or less as  
shipped from the factory.  
NOTE: Low NOx requirements apply only to natural gas  
installations.  
Rigging/Lifting of Unit (See Fig. 5)  
Lifting holes are provided in base rails as shown in Fig. 2 and 3.  
1. Leave top shipping skid on the unit for use as a spreader bar  
to prevent the rigging straps from damaging the unit. If the  
skid is not available, use a spreader bar of sufficient length  
to protect the unit from damage.  
2. Attach shackles, clevis pins, and straps to the base rails of  
the unit. Be sure materials are rated to hold the weight of the  
unit (See Fig. 5).  
3. Attach a clevis of sufficient strength in the middle of the  
straps. Adjust the clevis location to ensure unit is lifted level  
with the ground.  
!
WARNING  
CARBON MONOXIDE POISONING HAZARD  
Failure to follow this warning could result in personal  
injury or death.  
The venting system is designed to ensure proper venting.  
The flue hood assembly must be installed as indicted in this  
section of the unit installation instructions.  
After the unit is placed on the roof curb or mounting pad, remove  
the top skid.  
Step 6 — Connect Condensate Drain  
NOTE: When installing condensate drain connection be sure to  
Install the flue hood as follows:  
1. This installation must conform with local building codes  
and with the National Fuel Gas Code (NFGC) NFPA 54 /  
ANSI Z223.1, (in Canada, CAN/CGA B149.1, and  
B149.2) latest revision. Refer to Provincial and local  
plumbing or wastewater codes and other applicable local  
codes.  
comply with local codes and restrictions.  
Model 48EZ--A disposes of condensate water through a 3/4 in.  
NPT fitting which exits through the compressor access panel (See  
Fig. 2 and 3 for location).  
Condensate water can be drained directly onto the roof in rooftop  
installations (where permitted) or onto a gravel apron in ground  
level installations. Install a field--supplied condensate trap at end  
of condensate connection to ensure proper drainage. Make sure that  
the outlet of the trap is at least 1 in. (25 mm) lower than the  
drain--pan condensate connection to prevent the pan from  
overflowing (See Fig. 6). Prime the trap with water. When using a  
gravel apron, make sure it slopes away from the unit.  
If the installation requires draining the condensate water away  
from the unit, install a 2--in. (51 mm) trap at the condensate  
connection to ensure proper drainage (See Fig. 6). Make sure that  
the outlet of the trap is at least 1 in. (25 mm) lower than the  
drain--pan condensate connection. This prevents the pan from  
overflowing.  
Prime the trap with water. Connect a drain tube -- using a minimum  
of 3/4--in. PVC or 3/4--in. copper pipe (all field--supplied) -- at the  
outlet end of the 2--in. (51 mm) trap. Do not undersize the tube.  
Pitch the drain tube downward at a slope of at least 1--in. (25 mm)  
for every 10 ft (3 m) of horizontal run. Be sure to check the drain  
tube for leaks.  
2. Remove flue hood from shipping location (inside the return  
section of the blower compartment--see Fig. 8). Remove the  
return duct cover to locate the flue hood. Place flue hood  
assembly over flue panel. Orient screw holes in flue hood  
with holes in the flue panel.  
3. Secure flue hood to flue panel by inserting a single screw on  
the top flange and the bottom flange of the hood.  
Step 8 — Install Gas Piping  
The gas supply pipe enters the unit through the access hole  
provided. The gas connection to the unit is made to the 1/2--in.  
(12.7 mm) FPT gas inlet on the gas valve.  
Install a gas supply line that runs to the heating section. Refer to  
Table 2 and the NFGC for gas pipe sizing. Do not use cast--iron  
pipe. It is recommended that a black iron pipe is used. Check the  
local utility for recommendations concerning existing lines. Size  
gas supply piping for 0.5 IN. W.C. maximum pressure drop. Never  
use pipe smaller than the 1/2--in. (12.7 mm) FPT gas inlet on the  
unit gas valve.  
For natural gas applications, the gas pressure at unit gas connection  
must not be less than 4.0 IN. W.C. or greater than 13 IN. W.C.  
while the unit is operating. For propane applications, the gas  
pressure must not be less than 11.0 IN. W.C. or greater than 13 IN.  
W.C. at the unit connection.  
7
Download from Www.Somanuals.com. All Manuals Search And Download.  
A 1/8--in. (3.2 mm) NPT plugged tapping, accessible for test gauge  
connection, must be installed immediately upstream of the gas  
supply connection to the gas valve.  
!
WARNING  
When installing the gas supply line, observe local codes pertaining  
to gas pipe installations. Refer to the NFGC NFPA 54/ANSI  
Z223.1 latest edition (in Canada, CAN/CGA B149.1).  
FIRE OR EXPLOSION HAZARD  
Failure to follow this warning could result in personal injury,  
death and/or property damage.  
NOTE: In the state of Massachusetts:  
--Connect gas pipe to unit using a backup wrench to avoid  
damaging gas controls.  
1. Gas supply connections MUST be performed by a licensed  
plumber or gas fitter.  
--Never purge a gas line into a combustion chamber. Never  
test for gas leaks with an open flame. Use a commercially  
available soap solution made specifically for the detection of  
leaks to check all connections.  
2. When flexible connectors are used, the maximum length  
shall not exceed 36 in. (915 mm).  
3. When lever handle type manual equipment shutoff valves  
are used, they shall be T--handle valves.  
4. The use of copper tubing for gas piping is NOT approved  
by the state of Massachusetts.  
--Use proper length of pipe to avoid stress on gas control  
manifold.  
In the absence of local building codes, adhere to the following  
pertinent recommendations:  
--If a flexible connector is required or allowed by authority  
having jurisdiction, black iron pipe shall be installed at  
furnace gas valve and extend a minimum of 2 in. (51 mm)  
outside furnace casing.  
1. Avoid low spots in long runs of pipe. Grade all pipe 1/4 in.  
(6.35 mm) for every 15 ft (4.6 m) of length to prevent traps.  
Grade all horizontal runs downward to risers. Use risers to  
connect to heating section and to meter.  
2. Protect all segments of piping system against physical and  
thermal damage. Support all piping with appropriate straps,  
hangers, etc. Use a minimum of one hanger every 6 ft (1.8  
m). For pipe sizes larger than 1/2 in., (12.7 mm) follow  
recommendations of national codes.  
3. Apply joint compound (pipe dope) sparingly and only to  
male threads of joint when making pipe connections. Use  
only pipe dope that is resistant to action of liquedfied  
petroleum gases as specified by local and/or national codes.  
Never use Teflon tape.  
--If codes allow a flexible connector, always use a new  
connector. Do not use a connector which has previously  
serviced another gas appliance.  
8. Check for gas leaks at the field--installed and  
factory--installed gas lines after all piping connections have  
been completed. Use a commercially available soap solution  
made specifically for the detection of leaks (or method  
specified by local codes and/or regulations).  
IN  
4. Install sediment trap in riser leading to heating section (See  
Fig. 7). This drip leg functions as a trap for dirt and  
condensate.  
5. Install an accessible, external, manual main shutoff valve in  
gas supply pipe within 6 ft (1.8 m) of heating section.  
6. Install ground--joint union close to heating section between  
unit manual shutoff and external manual main shut--off  
valve.  
7. Pressure test all gas piping in accordance with local and  
national plumbing and gas codes before connecting piping  
to unit.  
TEE  
OUT  
NOTE: Pressure test the gas supply system after the gas supply  
piping is connected to the gas valve. The supply piping must be  
disconnected from the gas valve during the testing of the piping  
systems when test pressure is in excess of 0.5 psig. Pressure test the  
gas supply piping system at pressures equal to or less than 0.5 psig.  
The unit heating section must be isolated from the gas piping  
system by closing the external main manual shutoff valve and  
slightly opening the ground--joint union.  
NIPPLE  
CAP  
C99020  
Fig. 7 -- Sediment Trap  
8
Download from Www.Somanuals.com. All Manuals Search And Download.  
3. Use flexible transition between rigid ductwork and unit to  
prevent transmission of vibration. The transition may be  
screwed or bolted to duct flanges. Use suitable gaskets to  
ensure weather tight and airtight seal.  
Step 9 — Install Duct Connections  
The unit has duct flanges on the supply-- and return--air openings  
on the side and bottom of the unit. For downshot applications, the  
ductwork connects to the roof curb (See Fig. 2 and 3 for  
connection sizes and locations).  
4. All units must have field--supplied filters or accessory filter  
rack installed in the return--air side of the unit.  
Recommended sizes for filters are shown in Table 1.  
Configuring Units for Downflow (Vertical) Discharge  
5. Size all ductwork for maximum required airflow (either  
heating or cooling) for unit being installed. Avoid abrupt  
duct size increases or decreases or performance may be  
affected.  
!
WARNING  
ELECTRICAL SHOCK HAZARD  
6. Adequately insulate and weatherproof all ductwork located  
outdoors. Insulate ducts passing through unconditioned  
space, and use vapor barrier in accordance with latest issue  
of Sheet Metal and Air Conditioning Contractors National  
Association (SMACNA) and Air Conditioning Contractors  
of America (ACCA) minimum installation standards for  
heating and air conditioning systems. Secure all ducts to  
building structure.  
Failure to follow this warning could result in personal injury  
or death.  
Before installing or servicing system, always turn off main  
power to system and install lockout tag. There may be more  
than one disconnect switch.  
1. Open all electrical disconnects before starting any service  
work.  
7. Flash, weatherproof, and vibration--isolate all openings in  
building structure in accordance with local codes and good  
building practices.  
2. Remove horizontal (metal) duct covers to access vertical  
(downflow) discharge duct knockouts in unit basepan. (See  
Fig. 8.)  
!
CAUTION  
PROPERTY DAMAGE HAZARD  
Failure to follow this caution may result in property damage.  
Collect ALL screws that were removed. Do not leave screws  
on rooftop as permanent damage to the roof may occur.  
To remove downflow return and supply knockout covers, break  
front and right side connecting tabs with a screwdriver and  
hammer. Push cover down to break rear and left side tabs.  
Horizontal Duct Covers  
NOTE: These panels are held in place with tabs similar to an  
electrical knockout. Reinstall horizontal duct covers (Fig. 8)  
shipped on unit from factory. Insure openings are air and  
watertight.  
A09061  
Basepan  
Downflow  
(Vertical)  
Supply  
Knockout  
Basepan  
Downflow  
(Vertical)  
Return  
NOTE: The design and installation of the duct system must be in  
accordance with the standards of the NFPA for installation of  
nonresidence--type air conditioning and ventilating systems, NFPA  
90A or residence--type, NFPA 90B; and/or local codes and  
ordinances.  
Knockout  
Adhere to the following criteria when selecting, sizing, and  
installing the duct system:  
A09060  
Fig. 8 -- Supply and Return Duct Opening  
1. Units are shipped for horizontal duct installation (by  
removing duct covers).  
2. Select and size ductwork, supply--air registers, and  
return--air grilles according to American Society of Heating,  
Refrigeration and Air Conditioning Engineers (ASHRAE)  
recommendations.  
9
Download from Www.Somanuals.com. All Manuals Search And Download.  
Table 1 – Physical Data -- Unit 48EZ--A  
UNIT SIZE 48EZ ---A  
NOMINAL CAPACITY ---ton  
SHIPPING WEIGHT ---lb.  
(kg)  
24040  
2
24060  
2
30040  
2 --- 1/2  
373  
30060  
2 --- 1/2  
373  
36060  
3
36090  
3
42060  
3 --- 1/2  
461  
42090  
3 --- 1/2  
461  
359  
163  
359  
163  
379  
172  
379  
172  
169  
169  
209  
209  
COMPRESSORS  
Quantity  
Scroll  
1
REFRIGERANT (R---410A)  
Quantity ---lb  
8.3  
3.8  
8.3  
3.8  
10.2  
4.6  
10.2  
4.6  
7.9  
3.6  
7.9  
3.6  
10.0  
4.5  
10.0  
4.5  
(kg)  
REFRIGERANT METERING  
DEVICE  
In door --- T X V, Ou tdoor --- Accu r ater  
OUTDOOR ORIFICE  
0.038 (Left)  
0.040(Right)  
.97/1.02  
in. (qty)  
(mm)  
0.032 (2)  
.81  
0.035 (2)  
.89  
0.037 (2)  
.94  
OUTDOOR COIL  
Rows...Fins/in.  
2...21  
11.9  
2...21  
11.9  
2...21  
2...21  
11.9  
2...21  
11.9  
2...21  
11.9  
2...21  
2...21  
13.6  
11.9  
13.6  
Fa c e A r e a --- s q f t  
OUTDOOR FAN  
2000  
24  
610  
2000  
24  
610  
2700  
24  
610  
2700  
24  
610  
2700  
24  
610  
2700  
24  
610  
3100  
26  
660  
3100  
26  
660  
Nominal Cfm  
Diameter---in.  
(mm)  
1/5 (810)  
1/5 (810)  
1/5 (810)  
1/5 (810)  
1/5 (810)  
1/5 (810)  
1/5 (810)  
1/5 (810)  
Motor Hp (Rpm)  
INDOOR COIL  
3...17  
3.7  
3...17  
3.7  
3...17  
3.7  
3...17  
3.7  
3...17  
3.7  
3...17  
3.7  
3...17  
4.7  
3...17  
4.7  
Rows...Fins/in.  
Fa c e A r e a --- s q f t  
INDOOR BLOWER  
Nominal Cooling Airflow---(CFM)  
S i z e --- i n .  
800  
10x10  
254x254  
1/2  
800  
10x10  
254x254  
1/2  
1000  
10x10  
254x254  
1/2  
1000  
10x10  
254x254  
1/2  
1200  
11x10  
279x254  
3/4  
1200  
11x10  
279x254  
3/4  
1400  
11x10  
279x254  
3/4  
1400  
11x10  
279x254  
3/4  
(mm)  
M o t o r --- h p  
FURNACE SECTION*  
Burner Orifice  
Natural Gas Qty...Drill Size (Factory Installed)  
Propane GasQty...Drill Size  
HIGH---PRESSURE SWITCH  
( p s i g ) C u t --- o u t  
2...44  
2...55  
2...38  
2...53  
2...44  
2...55  
2...38  
2...53  
2...38  
2...53  
3...38  
3...53  
2...38  
2...53  
3...38  
3...53  
650 +/---15  
420 +/---25  
Reset (Auto)  
L O S S --- O F --- C H A R G E /  
LOW---PRESSURE SWITCH  
(Liquid Line) (psig)  
C u t --- o u t  
20 +/ --- 5  
45 +/---10  
Reset (auto)  
RETURN---AIR FILTERS † }  
Throwaway (in.)  
(mm)  
20x20x1  
508x508x25  
20x24x1  
508x610x25  
24x30x1  
610x762x25  
*Based on altitude of 0 to 2000 ft (0---610 m).  
{Required filter sizes shown are based on the larger of the AHRI (Air Conditioning, Heating and Refrigeration Institute) rated cooling airflow or the heating airflow  
velocity of 300 ft/minute for high---capacity type. Air filter pressure drop for non---standard filters must not exceed 0.08 IN. W.C.  
} If using accessory filter rack refer to filter rack installation instructions for correct filter size and quantity.  
10  
Download from Www.Somanuals.com. All Manuals Search And Download.  
Table 1 -- Physical Data -- Unit 48EZ--A (Cont’d)  
UNIT SIZE 48EZ ---A  
NOMINAL CAPACITY ---ton  
OPERATING WEIGHT---lb  
48090  
4
482  
219  
48115  
4
48130  
4
482  
219  
60090  
5
507  
230  
60115  
5
60130  
5
507  
230  
482  
219  
507  
230  
(kg)  
COMPRESSORS  
Quantity  
Scroll  
1
REFRIGERANT (R---410A)  
Quantity ---lb  
9.6  
4.4  
12.3  
5.6  
(kg )  
REFRIGERANT METERING DEVICE  
OUTDOOR ORIFICE---in. (qty)  
(mm)  
TXV  
0.046 (2)  
1.2  
0.052 (2)  
1.3  
OUTDOOR COIL  
Rows...Fins---in.  
2...21  
13.6  
2...21  
13.6  
2...21  
13.6  
2...21  
17.5  
2...21  
17.5  
2...21  
17.5  
Fa c e A r e a --- s q f t  
OUTDOOR FAN  
3100  
26  
660  
3100  
26  
660  
3100  
26  
660  
3500  
26  
660  
3500  
26  
660  
3500  
26  
660  
Nominal Cfm  
Diameter---in.  
(mm)  
1/5 (810)  
1/5 (810)  
1/5 (810)  
1/5 (810)  
1/5 (810)  
1/5 (810)  
M o t o r H p --- R p m  
INDOOR COIL  
3...17  
4.7  
3...17  
4.7  
3...17  
4.7  
3...17  
5.7  
3...17  
5.7  
3...17  
5.7  
Rows...Fins---in.  
Fa c e A r e a --- s q f t  
INDOOR BLOWER  
Nominal Cooling Airflow---(CFM)  
S i z e --- i n .  
1600  
11x10  
279x254  
1.0  
1600  
11x10  
279x254  
1.0  
1600  
11x10  
279x254  
1.0  
1850  
11x10  
279x254  
1.0  
1850  
11x10  
279x254  
1.0  
1850  
11x10  
279x254  
1.0  
(mm)  
M o t o r --- h p  
FURNACE SECTION*  
Burner Orifice  
3...38  
3...53  
3...33  
3...51  
3...31  
3...49  
3...38  
3...53  
3...33  
3...51  
3...31  
3...49  
Natural Gas Qty...Drill Size (Factory Installed)  
Propane GasQty...Drill Size  
HIGH---PRESSURE SWITCH (psig) Cut---out  
Reset (Auto)  
650 +/---15  
420 +/---25  
L O S S --- O F --- C H A R G E /  
LOW---PRESSURE SWITCH  
(Liquid Line) (psig)  
C u t --- o u t  
20 +/ --- 5  
45 +/---10  
Reset (auto)  
RETURN---AIR FILTERS †  
Throwaway (in.)  
(mm)  
24x36x1  
(610x914x25)  
*Based on altitude of 0 to 2000 ft (0---610 m).  
{Required filter sizes shown are based on the larger of the AHRI (Air Conditioning, Heating and Refrigeration Institute) rated cooling airflow or the heating airflow  
velocity of 300 ft/minute for high---capacity type. Air filter pressure drop for non---standard filters must not exceed 0.08 IN. W.C.  
} If using accessory filter rack refer to filter rack installation instructions for correct filter size and quantity.  
Table 2 – Maximum Gas Flow Capacity*  
NOMINAL  
IRON  
PIPE,  
SIZE (IN.)  
1/2  
LENGTH OF PIPE, FT† (m)  
INTERNAL  
DIAMETER  
(IN.)  
10  
20  
30  
40  
50  
60  
70  
(21.3)  
80  
(24.4)  
90  
(27.4)  
100  
125  
150  
175  
200  
(3.1)  
(6.1)  
(9.1)  
(12.2)  
(15.2)  
(18.3)  
(30.5)  
(38.1)  
(46.0)  
(53.3)  
(61.0)  
.622  
.824  
1.049  
1.380  
1.610  
175  
360  
120  
250  
97  
200  
375  
770  
1180  
82  
73  
66  
61  
57  
53  
50  
44  
93  
175  
360  
550  
40  
84  
160  
325  
500  
77  
145  
300  
460  
72  
135  
280  
430  
3/4  
170  
320  
600  
990  
151  
285  
580  
900  
138  
260  
530  
810  
125  
240  
490  
750  
118  
220  
460  
690  
110  
205  
430  
650  
103  
195  
400  
620  
1
680  
465  
1 --- 1 / 4  
1400  
950  
1 --- 1 / 2  
2100  
1460  
* Capacity of pipe in cu ft of gas per hr for gas pressure of 0.5 psig or less. Pressure drop of 0.5---IN. W.C. (based on a 0.60 specific gravity gas). Refer to Table 2  
and National Fire Protection Association NFPA 54/ANSI Z223.1.  
† This length includes an ordinary number of fittings.  
Table 3 – Heating Inputs  
GAS SUPPLY PRESSURE (IN. W.C.)  
Natural{ Propane*{  
MANIFOLD PRESSURE  
(IN. W.C.)  
HEATING INPUT  
(BTUH)  
NUMBER OF  
ORIFICES  
Min  
4.0  
4.0  
4.0  
4.0  
4.0  
Max  
13.0  
13.0  
13.0  
13.0  
13.0  
Min  
11.0  
11.0  
11.0  
11.0  
11.0  
Max  
13.0  
13.0  
13.0  
13.0  
13.0  
Natural{  
3.23.8  
3.23.8  
3.23.8  
3.23.8  
3.23.8  
Propane*†  
10.0∼11.0  
10.0∼11.0  
10.0∼11.0  
10.0∼11.0  
10.0∼11.0  
40,000  
60,000  
90,000  
115,000  
130,000  
2
2
3
3
3
*When a unit is converted to propane, different size orifices must be used. See separate, natural---to---propane conversion kit instructions.  
{Based on altitudes from sea level to 2000 ft (610 m) above sea level. In U.S.A. for altitudes above 2000 ft (610 m), reduce input rating 4 percent for each addi-  
tional 1000 ft (305 m) above sea level. In Canada, from 2000 ft (610 m) above sea level to 4500 ft (1372 m) above sea level, derate the unit 10 percent.  
11  
Download from Www.Somanuals.com. All Manuals Search And Download.  
Step 10 — Install Electrical Connections  
HIGH VOLTAGE  
POWER LEADS  
(SEE UNIT WIRING  
LABEL)  
POWER  
SUPPLY  
!
WARNING  
ELECTRICAL SHOCK HAZARD  
EQUIP GR  
Failure to follow this warning could result in personal injury  
or death.  
FIELD-SUPPLIED  
FUSED DISCONNECT  
CONTROL BOX  
The unit cabinet must have an uninterrupted, unbroken  
electrical ground. This ground may consist of an electrical  
wire connected to the unit ground screw in the control  
compartment, or conduit approved for electrical ground when  
installed in accordance with NEC, NFPA 70 National Fire  
Protection Association (latest edition) (in Canada, Canadian  
Electrical Code CSA C22.1) and local electrical codes.  
WHT(W1)  
W
YEL(Y)  
Y
GRN(G)  
G
RED(R)  
THERMOSTAT  
(TYPICAL)  
R
LOW-VOLTAGE  
BRN(C)  
C
ORN(O)  
POWER LEADS  
(SEE UNIT  
WIRING LABEL)  
O
BLU (DH)  
DH  
GRA (Y2)  
!
3-Phase  
Only  
CAUTION  
UNIT COMPONENT DAMAGE HAZARD  
SPLICE BOX  
A09067  
Failure to follow this caution may result in damage to the unit  
being installed.  
Fig. 9 -- High and Control--Voltage Connections  
1. Make all electrical connections in accordance with NEC  
NFPA 70 (latest edition) and local electrical codes  
governing such wiring. In Canada, all electrical  
connections must be in accordance with CSA standard  
C22.1 Canadian Electrical Code Part 1 and applicable  
local codes. Refer to unit wiring diagram.  
2. Use only copper conductor for connections between  
field--supplied electrical disconnect switch and unit. DO  
NOT USE ALUMINUM WIRE.  
3. Locate the black and yellow wires connected to the line side  
of the contactor.  
4. Connect field L1 to black wire on connection 11 of the  
compressor contactor.  
5. Connect field wire L2 to yellow wire on connection 23 of  
the compressor contactor.  
Three--phase units:  
1. Run the high--voltage (L1, L2, L3) and ground lead into the  
control box.  
3. Be sure that high--voltage power to unit is within  
operating voltage range indicated on unit rating plate. On  
3--phase units, ensure phases are balanced within 2  
percent. Consult local power company for correction of  
improper voltage and/or phase imbalance.  
2. Connect ground lead to chassis ground connection.  
3. Locate the black and yellow wires connected to the line side  
of the contactor.  
4. Connect field L1 to black wire on connection 11 of the  
compressor contactor.  
4. Insulate low--voltage wires for highest voltage contained  
within conduit when low--voltage control wires are in  
same conduit as high--voltage wires.  
5. Connect field wire L3 to yellow wire on connection 13 of  
the compressor contactor.  
5. Do not damage internal components when drilling  
through any panel to mount electrical hardware, conduit,  
etc.  
6. Connect field wire L2 to blue wire from compressor.  
Special Procedures for 208-V Operation  
High-Voltage Connections  
When routing power leads into unit, use only copper wire between  
disconnect and unit. The high voltage leads should be in a conduit  
until they enter the duct panel; conduit termination at the duct  
panel must be watertight.  
!
WARNING  
ELECTRICAL SHOCK HAZARD  
The unit must have  
a
separate electrical service with  
a
Failure to follow this warning could result in personal injury  
or death.  
field--supplied, waterproof disconnect switch mounted at, or within  
sight from, the unit. Refer to the unit rating plate, NEC and local  
codes for maximum fuse/circuit breaker size and minimum circuit  
amps (ampacity) for wire sizing.  
The field--supplied disconnect switch box may be mounted on the  
unit over the high--voltage inlet hole when the standard power and  
low--voltage entry points are used (See Fig. 2 and 3 for acceptable  
location).  
Makesurethepower supplyto theunit isswitched OFFbefore  
making any wiring changes. Tag the disconnect switch with a  
suitable warning label. With disconnect switch open, move  
black wire from transformer (3/16 in.) terminal marked 230 to  
terminal marked 200. This retaps transformer to primary  
voltage of 208 vac.  
NOTE:  
Field supplied disconnect switch box should be  
positioned so that it does not cover up any of the unit gas  
combustion supply air louvers.  
!
WARNING  
See unit wiring label (Fig. 14 and 15) and Fig. 9 for reference  
when making high voltage connections. Proceed as follows to  
complete the high--voltage connections to the unit.  
ELECTRICAL SHOCK AND EXPLOSION HAZARD  
Failure to follow this warning could result in personal injury  
or death.  
Single phase units:  
Beforemakingany wiringchanges, makesurethe gassupply  
is switched off first. Then switch off the power supply to the  
unit and install lockout tag.  
1. Run the high--voltage (L1, L2) and ground lead into the  
control box.  
2. Connect ground lead to chassis ground connection.  
12  
Download from Www.Somanuals.com. All Manuals Search And Download.  
Control Voltage Connections  
Do not use any type of power--stealing thermostat. Unit control  
problems may result.  
PRE--START--UP  
!
WARNING  
Use no. 18 American Wire Gage (AWG) color--coded, insulated  
(35_C minimum) wires to make the control voltage connections  
between the thermostat and the unit. If the thermostat is located  
more than 100 ft (30.5 m) from the unit (as measured along the  
control voltage wires), use no. 16 AWG color--coded, insulated  
(35_C minimum) wires.  
Locate the seven (eight on 3--phase) low voltage thermostat leads  
in 24 volt splice box. See Fig. 9 for connection diagram. Run the  
low--voltage leads from the thermostat, through the control wiring  
inlet hole grommet (Fig. 2 and 3), and into the low--voltage splice  
box. Provide a drip loop before running wires through panel.  
Secure and strain relief all wires so that they do not interfere with  
operation of unit. A gray wire is standard on 3--phase unit for  
connection to an economizer.  
FIRE,EXPLOSION,ELECTRICAL SHOCKHAZARD  
Failure to follow this warning could result in personal injury,  
death or property damage.  
1. Follow recognized safety practices and wear protective  
goggles when checking or servicing refrigerant system.  
2. Do not operate compressor or provide any electric power  
to unit unless compressor terminal cover is in place and  
secured.  
3. Do not remove compressor terminal cover until all  
electrical sources are disconnected and tagged.  
4. Relieve and recover all refrigerant from system before  
touching or disturbing anything inside terminal box if  
refrigerant leak is suspected around compressor  
terminals.  
Balance Point Setting-Thermidistat or Hybrid  
Thermostat  
5. Never attempt to repair soldered connection while  
refrigerant system is under pressure.  
BALANCE POINT TEMPERATURE--The “balance point”  
temperature is a setting which affects the operation of the heating  
mode. This is a field--selected input temperature (range 5 to 55_F)  
(--15 to 12_C) where the Thermidistat or dual fuel thermostat will  
monitor outdoor air temperature and decide whether to enable or  
disable the heat pump. If the outdoor temperature is above the  
“balance point”, the heat pump will energize first to try to satisfy  
the indoor temperature demand. If the heat pump does not make a  
sufficient improvement within a reasonable time period (i.e. 15  
minutes), then the gas furnace will come on to satisfy the indoor  
temperature demand. If the outdoor temperature is below the  
“balance point”, the heat pump will not be allowed to operate (i.e.  
locked out), and the gas furnace will be used to satisfy the indoor  
temperature. There are three separate concepts which are related to  
selecting the final “balance point” temperature. Read each of the  
following carefully to determine the best “balance point” in a  
hybrid installation:  
6. Do not use torch to remove any component. System  
contains oil and refrigerant under pressure.  
To remove a component, wear protective goggles and  
proceed as follows:  
a. Shut off electrical power to unit and install lockout  
tag.  
b. Relieve and reclaim all refrigerant from system  
using both high-- and low--pressure ports.  
c. Cut component connecting tubing with tubing  
cutter and remove component from unit.  
d. Carefully unsweat remaining tubing stubs when  
necessary. Oil can ignite when exposed to torch  
flame.  
Proceed as follows to inspect and prepare the unit for initial  
start--up:  
1. Remove access panels (see Fig. 18).  
1. Capacity Balance Temperature: This is a point where the  
heat pump cannot provide sufficient capacity to keep up  
with the indoor temperature demand because of declining  
outdoor temperature. At or below this point, the furnace is  
needed to maintain proper indoor temperature.  
2. Economic Balance Temperature: Above this point, the heat  
pump is the most cost efficient to operate, and below this  
point the furnace is the most cost efficient to operate. This  
can be somewhat complicated to determine and it involves  
knowing the cost of gas and electricity, as well as the  
efficiency of the furnace and heat pump. For the most  
economical operation, the heat pump should operate above  
this temperature (assuming it has sufficient capacity) and the  
furnace should operate below this temperature.  
2. Read and follow instructions on all WARNING,  
CAUTION, and INFORMATION labels attached to, or  
shipped with, unit.  
3. Make the following inspections:  
a. Inspect for shipping and handling damages such as  
broken lines, loose parts, disconnected wires, etc.  
b. Inspect for oil at all refrigerant tubing connections and  
on unit base. Detecting oil generally indicates a  
refrigerant leak.  
c. Leak test all refrigerant tubing connections using  
electronic leak detector, halide torch, or liquid--soap  
solution. If a refrigerant leak is detected, see the Check  
for Refrigerant Leaks section.  
d. Inspect all field-- and factory--wiring connections. Be  
sure that connections are completed and tight.  
3. Comfort Balance Temperature: When the heat pump is  
operating below this point, the indoor supply air feels  
uncomfortable (i.e. too cool). This is purely subjective and  
will depend on the homeowner’s idea of comfort. Below  
this temperature the gas furnace should operate in order to  
satisfy the desire for indoor comfort.  
e. Ensure wires do not touch refrigerant tubing or sharp  
sheet metal edges.  
f. Inspect coil fins. If damaged during shipping and  
handling, carefully straighten fins with a fin comb.  
Transformer Protection  
!
The transformer is of the energy--limiting type. It is set to withstand  
a 30--sec. overload or shorted secondary condition. If an overload  
or short is present, correct overload condition and check for blown  
fuse on gas control board or Interface Fan Board. Replace fuse as  
required with correct size and rating.  
WARNING  
FIRE, EXPLOSION HAZARD  
Failure to follow this warning could result in personal injury,  
death or property damage.  
Do not purge gas supply into the combustion chamber. Do not  
use a match or other open flame to check for gas leaks. Use a  
commercially available soap solution made specifically for  
the detection of leaks to check all connections.  
13  
Download from Www.Somanuals.com. All Manuals Search And Download.  
4. Verify the following conditions:  
de--energized. The evaporator motor is de--ener-  
gized after a 90 sec. delay.  
d. GAS HEATING MODE  
a. Make sure gas line is free of air. Before lighting the unit  
for the first time, perform the following with the gas  
valve in the “OFF” position:  
Outdoor temperature below balance point setpoint of  
thermostat.  
NOTE: If the gas supply pipe was not purged before connecting  
the unit, it will be full of air. It is recommended that the ground  
joint union be loosened, and the supply line be allowed to purge  
until the odor of gas is detected. Never purge gas lines into a  
combustion chamber. Immediately upon detection of gas odor,  
retighten the union. Allow 5 minutes to elapse, then light unit.  
Heating Sequence of Operation  
(See Fig. 15 and 16 and unit wiring label.)  
On a call for heating, terminal W of the thermostat is energized,  
starting the induced--draft motor. When the pressure switch senses  
that the induced--draft motor is moving sufficient combustion air,  
the burner sequence begins. This function is performed by the  
integrated gas unit controller (IGC). The indoor (evaporator)--fan  
motor is energized 45 sec after flame is established. When the  
thermostat is satisfied and W is de--energized, the burners stop  
firing and the indoor (evaporator) fan motor shuts off after a  
45--sec time--off delay. Please note that the IGC has the capability  
to automatically reduce the indoor fan motor on delay and increase  
the indoor fan motor off delay in the event of high duct static  
and/or partially--clogged filter.  
b. Make sure that condenser--fan blade is correctly  
positioned in fan orifice. Leading edge of condenser--fan  
blade should be 1/2 in. (12 mm) maximum from fan  
orifice.  
c. Make sure that air filter(s) is in place.  
d. Make sure that condensate drain trap is filled with water  
to ensure proper drainage.  
e. Make sure that all tools and miscellaneous loose parts  
have been removed.  
NOTE: An LED (light--emitting diode) indicator is provided on  
the control board to monitor operation. The control board is  
located by removing the burner access panel (see Fig. 18). During  
normal operation, the LED is continuously on.  
START--UP  
Step 1 — Check for Refrigerant Leaks  
Proceed as follows to locate and repair a refrigerant leak and to  
charge the unit:  
Step 3 — Start--up Heating and Make Adjust-  
ments  
1. Locate leak and make sure that refrigerant system pressure  
has been relieved and reclaimed from both high-- and  
low--pressure ports.  
!
CAUTION  
2. Repair leak following Refrigerant Service procedures.  
NOTE: Install a bi--flow filter drier whenever the system has been  
opened for repair.  
UNIT COMPONENT DAMAGE HAZARD  
Failure to follow this caution may result in damage to the unit  
being installed.  
3. Add a small charge of R--410A refrigerant vapor to system  
and leak--test unit.  
Complete the required procedures given in the Pre--Start--Up  
section before starting the unit. Do not jumper any safety  
devices when operating the unit.  
4. Recover refrigerant from refrigerant system and evacuate to  
500 microns if no additional leaks are not found.  
5. Charge unit with Puron (R--410A) refrigerant, using an  
electronic scale. Refer to unit rating plate for required  
charge.  
Complete the required procedures given in the Pre--Start--Up  
section before starting the unit. Do not jumper any safety devices  
when operating the unit. Make sure that burner orifices are  
properly aligned. Unstable operation my occur when the burner  
orifices in the manifold are misaligned.  
Follow the lighting instructions on the heating section operation  
label (located on the inside of the control access panel) to start the  
heating section.  
Step 2 — Unit Sequence of Operation  
48EZ-A Sequence of Operation  
a. CONTINUOUS FAN  
(1.) Thermostat closes circuit R to G energizing the  
blower motor for continuous fan.  
b. COOLING MODE  
NOTE: Make sure that gas supply has been purged, and that all  
gas piping has been checked for leaks.  
(1.) If indoor temperature is above temperature set  
point thermostat closes circuits R to G, R to Y and  
R to O--The unit delivers cooling airflow.  
Check Heating Control  
Start and check the unit for proper heating control operation as  
follows (see furnace lighting instructions located on the inside of  
the control access panel):  
c. HEAT PUMP HEATING MODE  
Outdoor temperature above balance point setpoint of  
thermostat.  
1. Place room thermostat SYSTEM switch in the HEAT  
position and the fan switch is placed in AUTO position.  
2. Set the heating temperature control of the thermostat above  
room temperature.  
(1.) On a call for heating, terminals “Y” and “G“ of the  
Hybrid thermostat are energized. The “Y“ signal is  
sent to the Defrost Board (DB) terminal “Y”. The  
DB has a built in five minute anti--short cycle timer  
which will not allow the compressor to restart  
before the time delay has expired.  
3. The induced--draft motor will start.  
4. On a call for heating, the main burner should light within 5  
sec. of the spark being energized. If the burners do not light,  
there is a 22--sec. delay before another 5--sec. try. If the  
burners still do not light, this sequence is repeated. If the  
burners do not light within 15 minutes from the initial call  
for heat, there is a lockout. To reset the control, break the  
24--v power to W.  
(2.) “T2” energizes the compressor contactor via the  
High Pressure Switch (HPS) and Low Pressure  
Switch (LPS). The compressor and outdoor fan  
start. Thermostat “G” energizes the Interface Fan  
Board terminal “G”. The blower motor is energized  
through contacts of the IFB.  
(3.) When the thermostat removes the “Y” and “G”  
calls, the compressor contactor and outdoor fan are  
5. The evaporator fan will turn on 45 sec. after the flame has  
been established. The evaporator fan will turn off 45 sec.  
after the thermostat has been satisfied. Please note that the  
14  
Download from Www.Somanuals.com. All Manuals Search And Download.  
integrated gas unit controller (IGC) has the capability to  
automatically reduce the evaporator “ON” delay and in-  
crease the evaporator “OFF” delay in the event of high duct  
static and/or partially--clogged filter.  
When the gas supply being used has a different heating value or  
specific gravity, refer to national and local codes, or contact your  
distributor to determine the required orifice size.  
Check Gas Input  
Check gas input and manifold pressure after unit start--up (See  
Table 3). If adjustment is required proceed as follows:  
!
CAUTION  
UNIT DAMAGE HAZARD  
S The rated gas inputs shown in Table 3 are for altitudes from sea  
Failure to follow this caution may result in reduced unit  
and/or component life.  
level to 2000 ft (610 m) above sea level. These inputs are based  
3
Do Not redrill an orifice. Improper drilling (burrs,  
out--of--round holes, etc.) can cause excessive burner noise  
and misdirection of burner flame. If orifice hole appears  
damaged or it is suspected to have been redrilled, check  
orifice hole with a numbered drill bit of correct size.  
on natural gas with a heating value of 1025 Btu/ft at 0.60  
specific gravity, or propane gas with a heating value of 2500  
3
Btu/ft at 1.5 specific gravity.  
IN THE U.S.A.:  
The input rating for altitudes above 2,000 ft (610 m) must be  
reduced by 4% for each 1,000 ft (305 m) above sea level.  
Adjust Gas Input  
The gas input to the unit is determined by measuring the gas flow  
at the meter or by measuring the manifold pressure. Measuring the  
gas flow at the meter is recommended for natural gas units. The  
manifold pressure must be measured to determine the input of  
propane gas units.  
For installations below 2,000 ft (610 m), refer to the unit rating  
plate.  
For installations above 2,000 ft (610 m) multiply the input by on  
the rating plate by the derate multiplier in Table 4 for correct input  
rate.  
Measure Gas Flow (Natural Gas Units)  
Table 4 – Altitude Derate Multiplier for U.S.A.*  
DERATE MULTIPLIER  
Minor adjustment to the gas flow can be made by changing the  
manifold pressure. The manifold pressure must be maintained  
between 3.2 and 3.8 IN. W.C.  
ALTITUDE FT (M)  
PERCENT OF DERATE  
FACTOR{  
0---2000  
(0---610)  
0
1.00  
If larger adjustments are required, change main burner orifices  
following the recommendations of national and local codes.  
NOTE: All other appliances that use the same meter must be  
2001---3000*  
(610---914)  
8 --- 1 2  
0.90  
0.86  
0.82  
0.78  
0.74  
0.70  
0.66  
0.62  
3001---4000  
(315---1219)  
12---16  
16---20  
20---24  
24---28  
28---32  
32---36  
36---40  
turned off when gas flow is measured at the meter.  
4001---5000  
(1220---1524)  
Proceed as follows:  
5001---6000  
(1524---1829)  
1. Turn off gas supply to unit.  
2. Remove pipe plug on manifold (See Fig. 11) and connect  
manometer. Turn on gas supply to unit.  
3. Record number of seconds for gas meter test dial to make  
one revolution.  
6001---7000  
(1829---2134)  
7001---8000  
(2134---2438)  
8001---9000  
(2439---2743)  
4. Divide number of seconds in Step 3 into 3600 (number of  
seconds in one hr).  
9001---10,000  
(2744---3048)  
*In Canada see Canadian Altitude Adjustment.  
{Derate multiplier factors are based on midpoint altitude for altitude range.  
BURNER FLAME  
BURNER  
MANIFOLD  
C99021  
Pipe Plug  
Manifold  
Fig. 10 -- Monoport Burner  
A07679  
IN CANADA:  
Fig. 11 -- Burner Assembly  
The input rating for altitudes from 2,000 to 4,500 ft (610 m to  
1372 m) above sea level must be derated 10% by an authorized  
Gas Conversion Station or Dealer.  
5. Multiply result of Step 4 by the number of cubic feet (cu ft)  
shown for one revolution of test dial to obtain cubic feet (cu  
ft) of gas flow per hour.  
EXAMPLE:  
6. Multiply result of Step 5 by Btu heating value of gas to  
obtain total measured input in Btuh. Compare this value  
with heating input shown in Table 3 (Consult the local gas  
supplier if the heating value of gas is not known).  
90,000 Btu/hr Input Furnace Installed at 4300 ft (1311 m).  
Furnace Input Rate at  
Sea Level  
X
Derate Multiplier  
Factor  
= Furnace Input Rate at  
Installation Altitude  
90,000  
X
0.90  
=
81,000  
15  
Download from Www.Somanuals.com. All Manuals Search And Download.  
EXAMPLE: Assume that the size of test dial is 1 cu ft, one  
revolution takes 32 sec, and the heating value of the gas is 1050  
Btu/ft . Proceed as follows:  
is located by removing the control access panel (see Fig. 18).  
During normal operation, the LED is continuously on (See Table 5  
for error codes).  
3
1. 32 sec. to complete one revolution.  
Airflow and Temperature Rise  
2. 3600 ÷ 32 = 112.5.  
The heating section for each size unit is designed and approved for  
heating operation within the temperature--rise range stamped on the  
unit rating plate.  
3
3. 112.5 x 1 =112.5 ft of gas flow/hr.  
4. 112.5 x 1050 = 118,125 Btuh input.  
Table 7 shows the approved temperature rise range for each heating  
input, and the air delivery cfm at various temperature rises for a  
given external static pressure. The heating operation airflow must  
produce a temperature rise that falls within the approved range.  
Refer to Indoor Airflow and Airflow Adjustments section to adjust  
heating airflow when required.  
If the desired gas input is 115,000 Btuh, only a minor change in the  
manifold pressure is required.  
Observe manifold pressure and proceed as follows to adjust gas  
input:  
1. Remove regulator cover screw over plastic adjustment  
screw on gas valve (See Fig. 12).  
Limit Switches  
2. Turn plastic adjustment screw clockwise to increase gas  
input, or turn plastic adjustment screw counterclockwise to  
decrease input (See Fig. 12). Manifold pressure must be  
between 3.2 and 3.8 IN. W.C.  
Normally closed limit switch (LS) completes the control circuit.  
Should the leaving--air temperature rise above the maximum  
allowable temperature, the limit switch opens and the control  
circuit “breaks.” Any interruption in the control circuit instantly  
closes the gas valve and stops gas flow to the burners. The blower  
motor continues to run until LS resets.  
When the air temperature at the limit switch drops to the  
low--temperature setting of the limit switch, the switch closes and  
completes the control circuit. The direct--spark ignition system  
cycles and the unit returns to normal heating operation.  
Table 5 – LED Indications  
REGULATOR  
COVER SCREW  
PLASTIC  
ADJUSTMENT  
SCREW  
ON/OFF SWITCH  
REGULATOR SPRING  
(PROPANE - WHITE)  
(
NATURAL - SILVER)  
GAS PRESSURE  
REGULATOR  
STATUS CODE  
Normal Operation  
LED INDICATION  
ADJUSTMENT  
INLET  
2
On  
PRESSURE TAP  
No Power or Hardware Failure  
Limit Switch Fault  
Off  
2 Flashes  
3 Flashes  
4 Flashes  
5 Flashes  
6 Flashes  
7 Flashes  
8 Flashes  
9 Flashes  
Flame Sense Fault  
Four Consecutive Limit Switch Faults  
Ignition Lockout Fault  
Pressure Switch Fault  
MANIFOLD  
PRESSURE TAP  
A07751  
Fig. 12 -- Single--Stage Gas Valve  
Rollout Switch Fault  
Internal Control Fault  
Temporary 1 hr auto reset  
1
!
WARNING  
NOTES:  
1.This code indicates an internal processor fault that will reset itself in one  
hr. Fault can be caused by stray RF signals in the structure or nearby. This  
is a UL requirement.  
FIRE AND UNIT DAMAGE HAZARD  
Failure to follow this warning could result in personal  
injury or death and/or property damage.  
2. LED indicates acceptable operation. Do not change ignition control  
board.  
3. When W is energized the burners will remain on for a minimum of 60 sec.  
4. If more than one error mode exists they will be displayed on the LED in  
sequence.  
Unsafe operation of the unit may result if manifold pressure  
is outside this range.  
Rollout Switch  
3. Replace regulator cover screw on gas valve (See Fig. 12).  
The function of the rollout switch is to close the main gas valve in  
the event of flame rollout. The switch is located above the main  
burners. When the temperature at the rollout switch reaches the  
maximum allowable temperature, the control circuit trips, closing  
the gas valve and stopping gas flow to the burners. The indoor  
(evaporator) fan motor (IFM) and induced draft motor continue to  
run until switch is reset. The IGC LED will display FAULT CODE  
7.  
4. Turn off gas supply to unit. Remove manometer from  
pressure tap and replace pipe plug on gas valve. (See Fig.  
11.) Turn on gas to unit and check for leaks.  
Measure Manifold Pressure (Propane Units)  
Refer to propane kit installation instructions for properly checking  
gas input.  
NOTE: For installations below 2,000 ft (610 m), refer to the unit  
rating plate for proper propane conversion kit. For installations  
above 2,000 ft (610 m), contact your distributor for proper propane  
conversion kit.  
Step 4 — Start--up Cooling and Make Adjust-  
ments  
Complete the required procedures given in the Pre--Start--Up  
section before starting the unit. Do not jumper any safety devices  
when operating the unit. Do not operate the compressor when the  
outdoor temperature is below 40°F (4.4°C) (unless accessory  
low--ambient kit is installed). Do not rapid--cycle the compressor.  
Allow 5 minutes between on cycles to prevent compressor damage.  
Check Burner Flame  
With control access panel (see Fig. 18) removed, observe the unit  
heating operation. Watch the burner flames to see if they are light  
blue and soft in appearance, and that the flames are approximately  
the same for each burner. Propane will have blue flame (See Fig.  
10). Refer to the Maintenance section for information on burner  
removal.  
Checking Cooling Control Operation  
Start and check the unit for proper cooling control operation as  
follows:  
Normal Operation  
An LED (light--emitting diode) indicator is provided on the  
integrated gas unit controller (IGC) to monitor operation. The IGC  
1. Place room thermostat SYSTEM switch in OFF position.  
Observe that blower motor starts when FAN switch is  
16  
Download from Www.Somanuals.com. All Manuals Search And Download.  
placed in ON position and shuts down when FAN switch is  
placed in AUTO position.  
refrigerant if actual temperature is more than 2°F (1.1°C)  
lower than required liquid line temperature.  
2. Place SYSTEM switch in COOL position and FAN switch  
in AUTO position. Set cooling control below room  
temperature. Observe that compressor, condenser fan, and  
evaporator blower motors start. Observe that cooling cycle  
shuts down when control setting is satisfied. The evaporator  
fan will continue to run for 90 sec.  
NOTE: If the problem causing the inaccurate readings is a  
refrigerant leak, refer to the Check for Refrigerant Leaks section.  
Indoor Airflow and Airflow Adjustments  
!
CAUTION  
IMPORTANT:  
Three--phase, scroll compressors units are  
direction oriented. Unit must be checked to ensure proper  
compressor 3--phase power lead orientation. If not corrected within  
5 minutes, the internal protector will shut off the compressor. The  
3--phase power leads to the unit must be reversed to correct  
rotation. When turning backwards, the difference between  
compressor suction and discharge pressures will be near zero.  
UNIT OPERATION HAZARD  
Failure to follow this caution may result in unit damage.  
For cooling operation, the recommended airflow is 350 to  
450 cfm for each 12,000 Btuh of rated cooling capacity. For  
heating operation, the airflow must produce a temperature  
rise that falls within the range stamped on the unit rating  
plate.  
Checking and Adjusting Refrigerant Charge  
NOTE: Be sure that all supply--and return--air grilles are open,  
free from obstructions, and adjusted properly.  
The refrigerant system is fully charged with PuronR (R--410A)  
refrigerant and is tested and factory sealed. Allow system to operate  
a minimum of 15 minutes before checking or adjusting charge.  
!
NOTE: Adjustment of the refrigerant charge is not required unless  
the unit is suspected of not having the proper PuronR (R--410A)  
charge.  
WARNING  
ELECTRICAL SHOCK AND EXPLOSION HAZARD  
Failure to follow this warning could result in personal  
injury or death.  
The charging label and the tables shown refer to system  
temperatures and pressures in cooling mode only. A refrigerant  
charging label is attached to the inside of the compressor access  
panel (see Fig. 18). The chart includes the required liquid line  
temperature at given discharge line pressures and outdoor ambient  
temperatures.  
Before making any indoor wiring adjustments, shut off gas  
supply. Then disconnect electrical power to the unit and  
install lockout tag before changing blower speed.  
This unit has independent fan speeds for gas heating and cooling.  
In addition, this unit has the field-selectable capability to run two  
different cooling fan speeds: A normal cooling fan speed (350~400  
CFM/Ton) and an enhanced dehumidification fan speed (As low as  
320 CFM/Ton) for use with either a dehumidistat or a thermostat  
that supports dehumidification.  
An accurate thermocouple-- or thermistor--type thermometer, and a  
gauge manifold are required when using the subcooling charging  
method for evaluating the unit charge. Do not use mercury or small  
dial--type thermometers because they are not adequate for this type  
of measurement.  
This unit is factory-set up for use with a single cooling fan speed.  
The cooling speed is marked “LOW” on the interface fan board  
(IFB) (See Fig. 13) . The factory-shipped settings are noted in  
Table 7. There are 3 additional speed tap wires available for use in  
either gas heating or cooling (For color coding on the indoor fan  
motor leads, see Table 6). The additional 3 speed tap wires are  
shipped loose with vinyl caps and are located in the control box,  
near the interface fan board (IFB) (See Fig. 13).  
!
CAUTION  
UNIT DAMAGE HAZARD  
Failure to follow this caution may result in unit damage.  
When evaluating the refrigerant charge, an indicated  
adjustment to the specified factory charge must always be  
very minimal. If a substantial adjustment is indicated, an  
abnormal condition exists somewhere in the cooling system,  
such as insufficient airflow across either coil or both coils.  
Gas Heating Fan Speed Set-up  
To change the gas heating speed:  
1. Remove the vinyl cap off of the desired speed tap wire  
(Refer to Table 6 for color coding). Table 7 shows the  
temperature rise associated with each fan speed for a given  
static pressure. Make sure that the speed chosen delivers a  
temperature rise within the rise range listed on the unit  
rating plate.  
Proceed as follows:  
1. Remove caps from low-- and high--pressure service fittings.  
2. Using hoses with valve core depressors, attach low-- and  
high--pressure gauge hoses to low-- and high--pressure  
service fittings, respectively.  
3. Start unit in Cooling Mode and let unit run until system  
pressures stabilize.  
2. Remove the current speed tap wire from the “GAS HEAT”  
terminal on the interface fan board (IFB) (Fig. 13) and place  
vinyl cap over the connector on the wire.  
4. Measure and record the following:  
3. Connect the desired speed tap wire to the “GAS HEAT”  
terminal on the interface fan board (IFB).  
a. Outdoor ambient--air temperature (°F [°C] db).  
b. Liquid line temperature (°F [°C]).  
c. Discharge (high--side) pressure (psig).  
d. Suction (low--side) pressure (psig) (for reference only).  
Single Cooling Fan Speed Set-up (Dehumidification  
feature not used)  
To change cooling speed:  
5. Using “Cooling Charging Charts,” compare outdoor--air  
temperature(°F [°C] db) with the discharge line pressure  
(psig) to determine desired system operating liquid line  
temperature (See Fig. 16).  
1. Remove the vinyl cap off of the desired speed tap wire  
(Refer to Table 6 for color coding). Add the wet coil  
pressure drop in Table 9 to the system static to determine the  
correct cooling airflow speed in Table 7 that will deliver the  
nominal cooling airflow as listed in Table 1 for each size.  
6. Compare actual liquid line temperature with desired liquid  
line temperature. Using a tolerance of ± 2°F (±1.1°C), add  
refrigerant if actual temperature is more than 2°F (1.1°C)  
higher than proper liquid line temperature, or remove  
17  
Download from Www.Somanuals.com. All Manuals Search And Download.  
2. Remove the current speed tap wire from the “LOW”  
terminal on the interface fan board (IFB) (See Fig. 13) and  
place vinyl cap over the connector on the wire.  
Continuous Fan Operation  
When the DEHUM feature is not used, the continuous fan speed  
will be the same as cooling fan speed. When the DEHUM feature  
is used, the continuous fan will operate on IFB “LOW” speed  
when the DH control lead is not energized, or IFB “HIGH” speed  
when the DH lead is energized (see Fig. 13).  
NOTE: For heat pump operation, the recommended airflow is 350  
to 450 CFM for each 12,000 Btuh of rated cooling capacity.  
3. Connect the desired speed tap wire to the “LOW” terminal  
on the interface fan board (IFB).  
Two Cooling Fan Speeds Set-up (Dehumidification  
feature used)  
IMPORTANT: Dehumidification control must open control  
circuit on humidity rise above set point.  
Table 6 – Color Coding for Indoor Fan Motor Leads  
Black = High Speed  
Use of the dehumidification cooling fan speed requires use of  
either a 24 VAC dehumidistat or a thermostat which includes  
control of a 24 VAC dehumidistat connection. In either case, the  
dehumidification control must open the control circuit on humidity  
rise above the dehumidification set point.  
Orange = Med---High Speed  
Red = Med Speed  
Pin k = Med --- L ow Speed  
Blue = Low Speed  
1. Remove fan speed tap wire from the “LOW” terminal on  
the interface fan board (IFB) (See Fig. 13).  
2. Determine correct normal cooling fan speed for unit and  
application. Add the wet coil pressure drop in Table 9 to  
the system static to determine the correct cooling airflow  
speed in Table 7 that will deliver the nominal cooling  
airflow as listed in Table 1 for each size.  
GAS  
HEAT  
HIGH  
QC7  
LOW  
QC4  
COM  
QC3  
QC6  
K2  
K1  
D2  
DCR  
QCR  
QC1  
C
RL3 C8 R1L  
Q1  
RI0  
3. Remove the vinyl cap off of the desired speed tap wire  
(Refer to Table 6 for color coding) for the normal cooling  
fan speed and place desired speed tap wire on “HIGH” on  
the interface board.  
JM6  
Q3  
RI2  
C9  
C4  
RI DL  
JM5  
G1  
G2  
4. Refer to airflow tables (Table 7) to determine allowable  
speeds for the dehumidification cooling fan speed. In Table  
7, speeds that are not allowed for dehumidification cooling  
are shaded.  
OILL C2 D6 D4  
A7  
R9 AB A15  
F1  
C0  
U1  
R4  
RL4  
C3  
D5 D3  
5. Remove the vinyl cap off of the desired speed tap wire  
(Refer to Table 6 for color coding) for the dehumidification  
cooling fan speed and place desired speed tap wire on the  
“LOW” connection on the interface board (IFB). Verify  
that static pressure is in the acceptable range for the speed  
tap to be used for dehumidification cooling.  
C7  
JW3  
R3 R5  
P2R6  
R2  
QCB  
JW7  
JW2  
JW4  
Y
Y
R
U
C
24VAC  
6. Use any spare vinyl plugs to cap any unused speed tap  
wires.  
JW1  
P1  
SSTZ-8  
Y2/  
DH  
Y1/  
W2  
G
Y
C
R
A09058  
Fig. 13 -- Interface Fan Board (IFB)  
18  
Download from Www.Somanuals.com. All Manuals Search And Download.  
19  
Download from Www.Somanuals.com. All Manuals Search And Download.  
20  
Download from Www.Somanuals.com. All Manuals Search And Download.  
21  
Download from Www.Somanuals.com. All Manuals Search And Download.  
22  
Download from Www.Somanuals.com. All Manuals Search And Download.  
23  
Download from Www.Somanuals.com. All Manuals Search And Download.  
24  
Download from Www.Somanuals.com. All Manuals Search And Download.  
25  
Download from Www.Somanuals.com. All Manuals Search And Download.  
26  
Download from Www.Somanuals.com. All Manuals Search And Download.  
A10207C  
Fig. 14 -- 208/230--1--60 Connection Wiring Diagram, Unit 48EZ--A  
27  
Download from Www.Somanuals.com. All Manuals Search And Download.  
A10207L  
Fig. 14 Cont -- 208/230--1--60 Ladder Wiring Diagram, Unit 48EZ--A  
28  
Download from Www.Somanuals.com. All Manuals Search And Download.  
A10208C  
Fig. 15 -- 208/230--3--60 Connection Wiring Diagram, Unit 48EZ--A  
29  
Download from Www.Somanuals.com. All Manuals Search And Download.  
A10208L  
Fig. 15 Cont. -- 208/230--3--60 Ladder Wiring Diagram, Unit 48EZ--A  
30  
Download from Www.Somanuals.com. All Manuals Search And Download.  
A08019  
Fig. 16 -- Cooling Charging Table--Subcooling  
31  
Download from Www.Somanuals.com. All Manuals Search And Download.  
3. Inspect blower motor and wheel for cleanliness at the  
beginning of each heating and cooling season. Clean when  
necessary. For first heating and cooling season, inspect  
blower wheel bi--monthly to determine proper cleaning  
frequency.  
4. Check electrical connections for tightness and controls for  
proper operation each heating and cooling season. Service  
when necessary. Ensure electrical wiring is not in contact  
with refrigerant tubing or sharp metal edges.  
MAINTENANCE  
To ensure continuing high performance and to minimize the  
possibility of premature equipment failure, periodic maintenance  
must be performed on this equipment. This combination  
heating/cooling unit should be inspected at least once each year by  
a qualified service person. To troubleshoot cooling or heating of  
units, refer to Tables 12, 13 and 14.  
NOTE: Consult your local dealer about the availability of a  
maintenance contract.  
5. Check and inspect heating section before each heating  
season. Clean and adjust when necessary.  
!
WARNING  
6. Check flue hood and remove any obstructions, if necessary.  
PERSONAL INJURY AND UNIT DAMAGE HAZARD  
Air Filter  
Failure to follow this warning could result in personal injury  
or death and unit component damage.  
IMPORTANT: Never operate the unit without a suitable air filter  
in the return--air duct system. Always replace the filter with the  
same dimensional size and type as originally installed. (See Table 1  
for recommended filter sizes.)  
The ability to properly perform maintenance on this  
equipment requires certain expertise, mechanical skills, tools  
and equipment. If you do not possess these, do not attempt to  
perform any maintenance on this equipment, other than those  
procedures recommended in the Owner’s Manual.  
Inspect air filter(s) at least once each month and replace  
(throwaway--type) or clean (cleanable--type) at least twice during  
each heating and cooling season or whenever the filter(s) becomes  
clogged with dust and/or lint.  
Indoor Blower and Motor  
NOTE: All motors are prelubricated. Do not attempt to lubricate  
these motors.  
!
WARNING  
ELECTRICAL SHOCK AND EXPLOSION HAZARD  
Failure to follow these warnings could result in personal  
injury or death:  
For longer life, operating economy, and continuing efficiency,  
clean accumulated dirt and grease from the blower wheel and  
motor annually.  
1. Turn off electrical power to the unit and install a lockout  
tag before performing any maintenance or service on this  
unit.  
!
WARNING  
2. Use extreme caution when removing panels and parts.  
ELECTRICAL SHOCK HAZARD  
3. Never place anything combustible either on or in contact  
with the unit.  
4. Should overheating occur or the gas supply fail to shut  
off, turn off external main manual gas valve to the unit.  
Then shut off electrical supply.  
Failure to follow this warning could result in personal injury  
or death.  
Disconnect and tag electrical powerto theunit beforecleaning  
and lubricating the blower motor and wheel.  
Cleaning the Blower Motor and Wheel  
1. Remove and disassemble blower assembly as follows:  
a. Remove blower access panel (see Fig. 18).  
b. Disconnect 5 pin plug and 4 pin plug from indoor  
blower motor. Remove capacitor if required.  
c. On all units, remove blower assembly from unit.  
Remove screws securing blower to blower partition and  
slide assembly out. Be careful not to tear insulation in  
blower compartment.  
!
CAUTION  
CUT HAZARD  
Failure to follow this caution may result in personal injury.  
When removing access panels (see Fig. 18) or performing  
maintenance functions inside your unit, be aware of sharp  
sheet metal parts and screws. Although special care is taken  
to reduce sharp edges to a minimum, be extremely careful  
when handling parts or reaching into the unit.  
d. Ensure proper reassembly by marking blower wheel and  
motor in relation to blower housing before disassembly.  
e. Loosen setscrew(s) that secures wheel to motor shaft.  
Remove screws that secure motor mount brackets to  
housing, and slide motor and motor mount out of  
housing.  
!
CAUTION  
2. Remove and clean blower wheel as follows:  
UNIT OPERATION HAZARD  
a. Ensure proper reassembly by marking wheel orientation.  
Failure to follow this caution may result in improper  
operation.  
b. Lift wheel from housing. When handling and/or  
cleaning blower wheel, be sure not to disturb balance  
weights (clips) on blower wheel vanes.  
Errors made when reconnecting wires may cause improper  
and dangerous operation. Label all wires prior to  
disconnecting when servicing.  
c. Remove caked--on dirt from wheel and housing with a  
brush. Remove lint and/or dirt accumulations from  
wheel and housing with vacuum cleaner, using soft  
brush attachment. Remove grease and oil with mild  
solvent.  
The minimum maintenance requirements for this equipment are as  
follows:  
1. Inspect air filter(s) each month. Clean or replace when  
necessary. Certain geographical locations may require more  
frequent inspections.  
d. Reassemble wheel into housing.  
e. Reassemble motor into housing. Be sure setscrews are  
tightened on motor shaft flats and not on round part of  
shaft. Reinstall blower into unit. Reinstall capacitor.  
2. Inspect indoor coil, outdoor coil, drain pan, and condensate  
drain each cooling season for cleanliness. Clean when  
necessary.  
32  
Download from Www.Somanuals.com. All Manuals Search And Download.  
f. Connect 5 pin plug and 4 pin plug to indoor blower  
motor.  
1. Remove the induced draft blower assembly according to  
directions in the Induced Draft Blower Assembly section.  
g. Reinstall blower access panel (see Fig. 18).  
2. Remove the 11 screws holding the flue collector box cover  
(See Fig. 17) to the heat exchanger assembly. Inspect the  
heat exchangers.  
3. Restore electrical power to unit. Start unit and check for  
proper blower rotation and motor speeds during heating and  
cooling cycles.  
3. Clean all surfaces, as required, using a wire brush.  
Limit Switch  
Integrated  
Gas Unit  
Controller  
(IGC)  
Remove blower access panel (see Fig. 18). Limit switch is located  
on the fan partition.  
Auto Transformer  
fuses used on 460  
volt units only.  
(Hidden)  
Burner Ignition  
Unit is equipped with a direct spark ignition 100 percent lockout  
system. Ignition module (IGC) is located in the control box (See  
Interface Fan  
Board (IFB)  
Fig. 17). Module contains  
a
self--diagnostic LED. During  
servicing, refer to label diagram or Table 5 in these instructions for  
LED interpretation.  
Induced Draft  
Motor  
If lockout occurs, unit may be reset by either momentarily  
interrupting power supply to unit or by turning selector switch to  
OFF position at the thermostat.  
Fan Partition  
Mounting  
Bracket  
Flue  
Collector  
Box  
Rollout  
Switch  
Inducer  
Blower  
Housing  
Burner  
Rack  
Mounting  
Screw  
Main Burners  
A09193  
At the beginning of each heating season, inspect for deterioration  
or blockage due to corrosion or other causes. Observe the main  
burner flames and adjust, if necessary.  
Fig. 17 -- Blower Housing and Flue Collector Box  
Removal of Gas Train  
To remove the gas train for servicing:  
1. Shut off main gas valve.  
2. Shut off power to unit and install lockout tag.  
3. Remove control access panel (See Fig. 18).  
4. Disconnect gas piping at unit gas valve.  
5. Remove fan partition mounting bracket (2 screws located  
on the left side of the control compartment on the fan parti-  
tion panel). Slide bracket forward, bottom first, to remove  
(See Fig. 17).  
6. Remove wires connected to gas valve. Mark each wire.  
7. Remove the mounting screw that attaches the burner rack to  
the unit base (See Fig. 17).  
CONTROL  
ACCESS  
PANEL  
BLOWER  
8. Partially slide the burner rack out of the unit (see Fig. 17  
and 20). Remove ignitor and sensor wires at the burner as-  
sembly. Remove rollout switch wires.  
ACCESS  
COMPRESSOR  
PANEL  
ACCESS PANEL  
A09207  
9. Slide the burner rack out of the unit (See Fig. 17 and 20).  
10. To reinstall, reverse the procedure outlined above.  
Fig. 18 -- Unit Access Panels  
Induced Draft (combustion air) Blower Assembly  
The induced--draft blower assembly consists of the inducer motor,  
the blower housing, and the induced--draft blower wheel.  
Clean periodically to assure proper airflow and heating efficiency.  
Inspect blower wheel every fall and periodically during the heating  
season. For the first heating season, inspect blower wheel  
bimonthly to determine proper cleaning frequency.  
To inspect blower wheel, remove draft hood assembly. Shine a  
flashlight into opening to inspect wheel. If cleaning is required,  
remove induced--draft blower assembly as follows:  
Outdoor Coil, Indoor Coil, and Condensate Drain Pan  
Inspect the outdoor coil, indoor coil, and condensate drain pan at  
least once each year. The coils are easily cleaned when dry;  
therefore, inspect and clean the coils either before or after each  
cooling season. Remove all obstructions, including weeds and  
shrubs, that interfere with the airflow through the condenser coil.  
Straighten bent fins with a fin comb. If coated with dirt or lint,  
clean the coils with a vacuum cleaner, using the soft brush  
attachment. Be careful not to bend the fins. If coated with oil or  
grease, clean the coils with a mild detergent--and--water solution.  
Rinse coils with clear water, using a garden hose. Be careful not to  
splash water on motors, insulation, wiring, or air filter(s). For best  
results, spray outdoor coil fins from inside to outside the unit. On  
units with an outer and inner condenser coil, be sure to clean  
between the coils. Be sure to flush all dirt and debris from the unit  
base.  
1. Remove control access panel (See Fig. 18).  
2. Remove the 5 screws that attach induced--draft blower as-  
sembly to the flue collector box cover.  
3. Slide the assembly out of the unit. (See 20). Clean the  
blower wheel. If additional cleaning is required, continue  
with Steps 4 and 5.  
Inspect the drain pan and condensate drain line when inspecting  
the coils. Clean the drain pan and condensate drain by removing all  
foreign matter from the pan. Flush the pan and drain tube with  
clear water. Do not splash water on the insulation, motor, wiring, or  
air filter(s). If the drain tube is restricted, clear it with a “plumbers  
snake” or similar probe device. Ensure that the auxiliary drain port  
above the drain tube is also clear.  
4. To remove blower wheel, remove 2 setscrews.  
5. To remove inducer motor, remove screws that hold the  
inducer motor to the blower housing.  
6. To reinstall, reverse the procedure outlined above.  
Flue Gas Passageways  
To inspect the flue collector box and upper areas of the heat  
exchanger:  
33  
Download from Www.Somanuals.com. All Manuals Search And Download.  
BLOWER  
HOUSING  
2 SETSCREWS  
(HIDDEN)  
A07680  
Fig. 22 -- Burner Rack Removed  
Outdoor Fan  
!
CAUTION  
UNIT OPERATION HAZARD  
C99085  
Failure to follow this caution may result in damage to unit  
components.  
Fig. 19 -- Removal of Motor and Blower Wheel  
Keep the outdoor fan free from all obstructions to ensure  
proper cooling operation. Never place articles on top of the  
unit.  
1. Remove 6 screws holding outdoor grille and motor to top  
cover.  
2. Turn motor/grille assembly upside down on top cover to  
expose the fan blade.  
3. Inspect the fan blades for cracks or bends.  
4. If fan needs to be removed, loosen the setscrew and slide the  
fan off the motor shaft.  
5. When replacing fan blade, position blade back to the same  
position as before.  
6. Ensure that setscrew engages the flat area on the motor shaft  
when tightening.  
A07680  
Fig. 20 -- Burner Rack Removed  
7. Replace grille.  
Electrical Controls and Wiring  
FEEDER TUBE  
STUB TUBE  
Inspect and check the electrical controls and wiring annually. Be  
sure to turn off the gas supply, and then the electrical power to the  
unit.  
Remove access panels (see Fig. 18) to locate all the electrical  
controls and wiring. Check all electrical connections for tightness.  
Tighten all screw connections. If any discolored or burned  
connections are noticed, disassemble the connection, clean all the  
parts, re--strip the wire end and reassemble the connection properly  
and securely.  
After inspecting the electrical controls and wiring, replace the  
access panels (see Fig. 18). Start the unit, and observe at least one  
complete heating cycle and one complete cooling cycle to ensure  
proper operation. If discrepancies are observed in any operating  
cycle, or if a suspected malfunction has occurred, check each  
electrical component with the proper electrical instrumentation.  
Refer to the unit wiring label when making these checkouts.  
DEFROST  
THERMOSTAT  
C99029  
Fig. 21 -- Defrost Thermostat Location  
NOTE: Refer to the heating and/or cooling sequence of operation  
in this publication as an aid in determining proper control  
operation.  
Refrigerant Circuit  
Annually inspect all refrigerant tubing connections and the unit  
base for oil accumulations. Detecting oil generally indicates a  
refrigerant leak.  
34  
Download from Www.Somanuals.com. All Manuals Search And Download.  
Speedup  
Pins  
Quiet  
Shift  
Defrost interval  
DIP switches  
A08020  
Fig. 23 -- Defrost Control  
the Indoor Airflow and Airflow Adjustments section to check the  
system airflow.  
!
WARNING  
Check Defrost Thermostat  
EXPLOSION,  
ENVIRONMENTAL HAZARD  
PERSONAL  
INJURY  
AND  
The defrost thermostat is usually located on the lowest liquid  
leaving circuit of the left condenser coil (see Fig. 21). The  
thermostat closes at 32_F (0_C) and opens at 65_F (18_C).  
Failure to follow this warning could result in personal injury,  
death or property damage.  
Puron Items  
System under pressure. Relieve pressure and recover all  
refrigerant before system repair or final unit disposal. Use all  
service ports and open all flow--control devices, including  
solenoid valves.  
Metering Device (Thermostatic Expansion Valve &  
Piston)  
This unit uses both a hard shutoff, balance port TXV in the indoor  
coil and a piston in each side of the outdoor coil. The TXV  
maintains a constant superheat at the evaporator coil exit (cooling  
mode) resulting in higher overall system efficiency.  
If oil is detected or if low cooling performance is suspected,  
leak--test all refrigerant tubing using an electronic leak--detector,  
halide torch, or liquid--soap solution. If a refrigerant leak is  
detected, refer to the Check for Refrigerant Leaks section.  
Pressure Switches  
Pressure switches are protective devices wired into control circuit  
(low voltage). They shut off compressor if abnormally high or low  
pressures are present in the refrigeration circuit. These pressure  
switches are specifically designed to operate with Puron (R--410A)  
systems. R--22 pressure switches must not be used as replacements  
for the Puron (R--410A) system.  
If no refrigerant leaks are found and low cooling performance is  
suspected, refer to the Checking and Adjusting Refrigerant Charge  
section.  
Gas Input  
The gas input does not require checking unless improper heating  
performance is suspected. If a problem exists, refer to the Start--Up  
section.  
Loss of Charge Switch  
This switch is located on the liquid line and protects against low  
suction pressures caused by such events as loss of charge, low  
airflow across indoor coil, dirty filters, etc. It opens on a pressure  
drop at about 20 psig. If system pressure is above this, switch  
should be closed. To check switch:  
Indoor Airflow  
The heating and/or cooling airflow does not require checking  
unless improper performance is suspected. If a problem exists, be  
sure that all supply-- and return--air grilles are open and free from  
obstructions, and that the air filter is clean. When necessary, refer to  
1. Turn off all power to unit.  
35  
Download from Www.Somanuals.com. All Manuals Search And Download.  
C99097  
Fig. 24 -- Refrigerant Circuit  
2. Disconnect leads on switch.  
The compressor is an electrical (as well as mechanical) device.  
Exercise extreme caution when working near compressors. Power  
should be shut off, if possible, for most troubleshooting techniques.  
Refrigerants present additional safety hazards.  
3. Apply ohm meter leads across switch. You should have  
continuity on a good switch.  
NOTE: Because these switches are attached to refrigeration  
system under pressure, it is not advisable to remove this device for  
troubleshooting unless you are reasonably certain that a problem  
exists. If switch must be removed, remove and recover all system  
charge so that pressure gauges read 0 psi. Never open system  
without breaking vacuum with dry nitrogen.  
!
WARNING  
EXPLOSION HAZARD  
Failure to follow this warning could result in personal injury  
or death and/or property damage.  
High--Pressure Switch  
Wear safety glasses and gloves when handling refrigerants.  
Keep torches and other ignition sources away from  
refrigerants and oils.  
The high--pressure switch is located in the discharge line and  
protects against excessive condenser coil pressure. It opens at 650  
psig.  
High pressure may be caused by a dirty outdoor coil, failed fan  
motor, or outdoor air recirculation. To check switch:  
The scroll compressor pumps refrigerant throughout the system by  
the interaction of a stationary and an orbiting scroll. The scroll  
compressor has no dynamic suction or discharge valves, and it is  
more tolerant of stresses caused by debris, liquid slugging, and  
flooded starts. The compressor is equipped with an internal  
pressure relief port. The pressure relief port is a safety device,  
designed to protect against extreme high pressure. The relief port  
has an operating range between 550 and 625 psig differential  
pressure.  
1. Turn off all power to unit.  
2. Disconnect leads on switch.  
3. Apply ohm meter leads across switch. You should have  
continuity on a good switch.  
Copeland Scroll Compressor (Puron Refrigerant)  
The compressor used in this product is specifically designed to  
operate with Puron (R--410A) refrigerant and cannot be  
interchanged.  
36  
Download from Www.Somanuals.com. All Manuals Search And Download.  
INDOOR COIL  
OUTDOOR COIL  
TXV in Metering  
Position  
LCS  
HPS  
Bypass  
Position  
LEGEND  
HPS – High Pressure Switch  
LCS – Loss of Charge Switch  
®
Accurater Metering Device  
Arrow indicates direction of flow  
C03011  
Fig. 25 -- Typical Heat Pump Operation, Cooling Mode  
INDOOR COIL  
OUTDOOR COIL  
TXV in Bypass  
Position  
LCS  
HPS  
Metering  
Position  
LEGEND  
HPS – High Pressure Switch  
LCS – Loss of Charge Switch  
®
Accurater Metering Device  
Arrow indicates direction of flow  
C03012  
Fig. 26 -- Typical Heat Pump Operation, Heating Mode  
Refrigerant System  
!
WARNING  
This information covers the refrigerant system of the 48EZ--A,  
including the compressor oil needed, servicing systems on roofs  
containing synthetic materials, the filter drier and refrigerant  
charging.  
UNIT OPERATION AND SAFETY HAZARD  
Failure to follow this warning could result in personal injury  
or equipment damage.  
Compressor Oil  
If additional oil is needed use Uniqema RL32--3MAF. If this oil is  
not available, use Copeland Ultra 32CC or Mobil Artic EAL22CC.  
This oil is extremely hygroscopic, meaning it absorbs water  
readily. POE oils can absorb 15 times as much water as other oils  
designed for HCFC and CFC refrigerants. Take all necessary  
precautions to avoid exposure of the oil to the atmosphere.  
This system uses Puron (R--410A) refrigerant which has  
higher operating pressures than R--22 and other refrigerants.  
No other refrigerant may be used in this system. Gauge set,  
hoses,andrecoverysystemmustbe designedto handlePuron.  
If you are unsure, consult the equipment manufacturer.  
37  
Download from Www.Somanuals.com. All Manuals Search And Download.  
Servicing Systems on Roofs and with Synthetic materials  
Liquid Line Filter Drier  
POE (polyolester) compressor lubricants are known to cause long  
term damage to some synthetic roofing materials.  
This filter drier is specifically designed to operate with Puron. Use  
only factory--authorized components. Filter drier must be replaced  
whenever the refrigerant system is opened. When removing a filter  
drier, use a tubing cutter to cut the drier from the system. Do not  
unsweat a filter drier from the system. Heat from unsweating will  
release moisture and contaminants from drier into system.  
Exposure, even if immediately cleaned up, may cause  
embrittlement (leading to cracking) to occur in one year or more.  
When performing any service that may risk exposure of  
compressor oil to the roof, take appropriate precautions to protect  
roofing. Procedures which risk oil leakage include, but are not  
limited to, compressor replacement, repairing refrigerant leaks,  
replacing refrigerant components such as filter drier, pressure  
switch, metering device, coil, accumulator, or reversing valve.  
Puron (R--410A) Refrigerant Charging  
Refer to unit information plate and charging chart. Some R--410A  
refrigerant cylinders contain a dip tube to allow liquid refrigerant to  
flow from cylinder in upright position. For cylinders equipped  
with a dip tube, charge Puron units with cylinder in upright  
position and a commercial metering device in manifold hose.  
Charge refrigerant into suction--line.  
Synthetic Roof Precautionary Procedure  
1. Cover extended roof working area with an impermeable  
polyethylene (plastic) drip cloth or tarp. Cover an  
approximate 10x10 ft (3x3 m) area.  
2. Cover area in front of the unit service panel with a terry  
cloth shop towel to absorb lubricant spills and prevent  
run--offs, and protect drop cloth from tears caused by tools  
or components.  
TROUBLESHOOTING  
Use the Troubleshooting Guides (See Tables 12--14) if problems  
occur with these units.  
START--UP CHECKLIST  
Use Start--Up checklist to ensure proper start--up procedures are  
followed.  
3. Place terry cloth shop towel inside unit immediately under  
component(s) to be serviced and prevent lubricant run--offs  
through the louvered openings in the unit base.  
4. Perform required service.  
5. Remove and dispose of any oil contaminated material per  
local codes.  
PURONR (R--410A) QUICK REFERENCE GUIDE  
S
Puron refrigerant operates at 50--70 percent higher pressures than R--22. Be sure that servicing equipment and replacement  
components are designed to operate with Puron  
S
S
S
Puron refrigerant cylinders are rose colored.  
Recovery cylinder service pressure rating must be 400 psig, DOT 4BA400 or DOT BW400.  
Puron systems should be charged with liquid refrigerant. Use a commercial type metering device in the manifold hose when  
charging into suction line with compressor operating  
S
S
S
S
S
S
S
S
S
S
S
S
S
S
S
Manifold sets should be minimum 700 psig high side and 180 psig low side with 550 psig low--side retard.  
Use hoses with minimum 700 psig service pressure rating.  
Leak detectors should be designed to detect HFC refrigerant.  
Puron, as with other HFCs, is only compatible with POE oils.  
Vacuum pumps will not remove moisture from oil.  
Do not use liquid--line filter driers with rated working pressures less than 600 psig.  
Do not leave Puron suction line filter driers in line longer than 72 hrs.  
Do not install a suction--line filter drier in liquid line.  
POE oils absorb moisture rapidly. Do not expose oil to atmosphere.  
POE oils may cause damage to certain plastics and roofing materials.  
Wrap all filter driers and service valves with wet cloth when brazing.  
A factory approved liquid--line filter drier is required on every unit.  
Do NOT use an R--22 TXV.  
Never open system to atmosphere while it is under a vacuum.  
When system must be opened for service, recover refrigerant, evacuate then break vacuum with dry nitrogen and replace filter  
driers. Evacuate to 500 microns prior to recharging.  
S
S
S
Do not vent Puron into the atmosphere.  
Observe all warnings, cautions, and bold text.  
All indoor coils must be installed with a hard shutoff Puron TXV metering device.  
38  
Download from Www.Somanuals.com. All Manuals Search And Download.  
Table 12 – Troubleshooting Guide -- Cooling or Heat Pump Heating Mode  
SYMPTOM  
CAUSE  
REMEDY  
Power Failure  
Call power company.  
Replace fuse or reset circuit breaker.  
Fuse blown or circuit breaker tripped  
Defective thermostat, contactor, transformer, or control  
relay  
Compressor and Outdoor fan will not  
start.  
Replace component.  
Insufficient line voltage  
Determine cause and correct.  
Incorrect or faulty wiring  
Check wiring diagram and rewire correctly.  
Lower thermostat setting below room temperature.  
Check wiring and repair or replace.  
Thermostat setting too high  
Faulty wiring or loose connections in compressor circuit  
Compressor motor burned out, seized, or internal over-  
load open  
Determine cause Replace compressor.  
Compressor will not start but Outdoor  
fan runs.  
Defective run/start capacitor, overload, start relay  
Determine cause and replace.  
Replace fuse or reset circuit breaker. Determine  
cause.  
One leg of 3---phase power dead  
Three---phase scroll compressor makes  
excessive noise, and there may  
be a low pressure differential.  
Correct the direction of rotation by reversing the  
3---phase power leads to the unit.  
Scroll compressor is rotating in the wrong direction  
Refrigerant overcharge or undercharge  
Recover refrigerant, evacuate system, and recharge  
to capacities shown on nameplate.  
Replace and determine cause.  
Determine cause and correct.  
Determine cause and correct.  
Determine cause and replace.  
Replace thermostat.  
Defective compressor  
Insufficient line voltage  
Compressor cycles (other than normally  
satisfying thermostat).  
Blocked Outdoor  
Defective run/start capacitor, overload or start relay  
Defective thermostat  
Faulty Outdoor---fan motor or capacitor  
Damaged reversing valve  
Restriction in refrigerant system  
Dirty air filter  
Replace.  
Determine cause and correct  
Locate restriction and remove.  
Replace filter.  
Unit undersized for load  
Thermostat set too low  
Low refrigerant charge  
Mechanical damage in compressor.  
Air in system  
Decrease load or increase unit size.  
Reset thermostat.  
Locate leak, repair, and recharge.  
Replace compressor.  
Recover refrigerant, evacuate system, and recharge.  
Check defrost time settings, Reset as necessary  
Check defrost temperature switch, Replace as nec-  
essary  
Compressor operates continuously.  
Excessive head pressure.  
Frosted coil with incorrect defrost operation  
Outdoor coil dirty or restricted  
Dirty air filter  
Dirty Indoor or Outdoor coil  
Refrigerant overcharged  
Air in system  
Indoor or Outdoor air restricted or air short---cycling  
Low refrigerant charge  
Compressor IPR leaking  
Restriction in liquid tube  
High heat load  
Compressor IPR leaking  
Refrigerant overcharged  
Reversing valve hung up or leaking internally  
Dirty air filter  
Low refrigerant charge  
Metering device or low side restricted  
Clean coil or remove restriction .  
Replace filter.  
Clean coil.  
Recover excess refrigerant.  
Recover refrigerant, evacuate system, and recharge.  
Determine cause and correct.  
Check for leaks, repair, and recharge.  
Replace compressor.  
Head pressure too low.  
Remove restriction.  
Check for source and eliminate.  
Replace compressor.  
Excessive suction pressure.  
Recover excess refrigerant.  
Replace valve  
Replace Filter.  
Check for leaks, repair, and recharge.  
Remove source of restriction.  
Increase air quantity. Check filter — replace if neces-  
sary.  
Insufficient Indoor airflow  
Suction pressure too low.  
Temperature too low in conditioned area  
Outdoor ambient below 55°F (12.8°C)  
Field---installed filter---drier restricted  
Reset thermostat.  
Install low---ambient kit.  
Replace.  
Move timer on control board to 30 minutes between  
defrost cycles  
(Heat) Outdoor coil frosted  
Compressor runs but outdoor fan does  
not  
Check condition of relay on board Replace if neces-  
sary  
NC (normally closed) contacts on defrost board open  
39  
Download from Www.Somanuals.com. All Manuals Search And Download.  
Table 13 – Troubleshooting Guide–Heating  
SYMPTOM  
CAUSE  
REMEDY  
Water in gas line  
Drain. Install drip leg.  
No power to furnace  
Check power supply fuses, wiring or circuit breaker.  
Check transformer.  
NOTE: Some transformers have internal over--current protection  
that requires a cool--down period to reset.  
No 24--v power supply to control circuit  
Burners will not ignite  
Mis--wired or loose connections  
Misaligned spark electrodes  
Check all wiring and wire nut connections  
Check flame ignition and sense electrode positioning.  
Adjust as necessary.  
1. Check gas line for air. Purge as necessary. NOTE: After purging  
gas line of air, wait at least 5 minutes for any gas to dissipate be-  
fore attempting to light unit.  
No gas at main burners  
2. Check gas valve.  
Dirty air filter  
Clean or replace filter as necessary  
Gas input to furnace too low  
Unit undersized for application  
Restricted airflow  
Check gas pressure at manifold match with that on unit nameplate  
Replace with proper unit or add additional unit  
Clean or replace filter. Remove any restriction.  
Inadequate heating  
Check rotation of blower, temperature rise of unit. Adjust as neces-  
sary.  
Limit switch cycles main burners  
1. Tighten all screws around burner compartment  
2. Cracked heat exchanger. Replace.  
3. Unit over--fired. Reduce input (change orifices or adjust gas line  
or manifold pressure).  
4. Check burner alignment.  
Incomplete combustion results in: Aldehyde odors,  
carbon monoxide, sooting flame, floating flame  
Poor flame characteristics  
5. Inspect heat exchanger for blockage. Clean as necessary.  
Table 14 – Troubleshooting Guide–LED Error Codes  
SYMPTOM  
CAUSE  
REMEDY  
Check 5--amp fuse son IGC*, power to unit, 24--v circuit breaker,  
and transformer. Units without a 24--v circuit breaker have an  
internal overload in the 24--v transformer. If the overload trips,  
allow 10 minutes for automatic reset.  
No Power or Hardware fail-  
ure  
(LED OFF)  
Loss of power to control module (IGC)*.  
Check the operation of the indoor (evaporator) fan motor. Ensure  
that the supply--air temperature rise is in accordance with the  
range on the unit nameplate. Clean or replace filters.  
Limit switch faults  
(LED 2 flashes)  
High temperature limit switch is open.  
The IGC* sensed flame that should not be present.  
Inadequate airflow to unit.  
Flame sense fault  
(LED 3 flashes)  
Reset unit. If problem persists, replace control board.  
4 consecutive limit switch  
faults  
(LED 4 flashes)  
Check the operation of the indoor (evaporator) fan motor and that  
supply--air temperature rise agrees with range on unit nameplate  
information.  
Check ignitor and flame sensor electrode spacing, gaps, etc.  
Ensure that fame sense and ignition wires are properly terminated.  
Verify that unit is obtaining proper amount of gas.  
Verify wiring connections to pressure switch and inducer motor.  
Verify pressure switch hose is tightly connected to both inducer  
housing and pressure switch. Verify inducer wheel is properly  
attached to inducer motor shaft. Verify inducer motor shaft is turn-  
ing.  
Ignition lockout  
(LED 5 flashes)  
Unit unsuccessfully attempted ignition for 15 minutes.  
Open pressure switch.  
Pressure Switch Fault  
(LED 6 flashes)  
Rollout switch will automatically reset, but IGC* will continue to  
lockout unit. Check gas valve operation. Ensure that induced--draft  
blower wheel is properly secured to motor shaft. Inspect heat  
exchanger. Reset unit at unit disconnect.  
Rollout switch fault  
(LED 7 flashes)  
Rollout switch has opened.  
Internal control fault  
(LED 8 flashes)  
Microprocessor has sensed an error in the software  
or hardware.  
If error code is not cleared by resetting unit power, replace the  
IGC*.  
Temporary 1 hr auto reset  
(LED 9 flashes)  
Reset 24--v. to control board or turn thermostat off, then on again.  
Fault will automatically reset itself in one (1) hour.  
Electrical interference impeding IGC software  
*WARNING  
: If the IGC must be replaced, be sure to ground yourself to dissipate any electrical charge that my be present before handling new control  
board. The IGC is sensitive to static electricity and my be damaged if the necessary precautions are not taken.  
IMPORTANT: Refer to Table 12---Troubleshooting Guide---Heating for additional troubleshooting analysis.  
LEGEND  
IGC—Integrated Gas Unit Controller  
LED—Light---Emitting Diode  
40  
Download from Www.Somanuals.com. All Manuals Search And Download.  
START--UP CHECKLIST  
(Remove and Store in Job Files)  
I. PRELIMINARY INFORMATION  
MODEL NO.:  
SERIAL NO.:  
DATE:  
TECHNICIAN:  
II. PRESTART--UP (Insert check mark in box as each item is completed)  
( ) VERIFY THAT ALL PACKING MATERIALS HAVE BEEN REMOVED FROM UNIT  
( ) REMOVE ALL SHIPPING HOLD DOWN BOLTS AND BRACKETS PER INSTALLATION INSTRUCTIONS  
( ) CHECK ALL ELECTRICAL CONNECTIONS AND TERMINALS FOR TIGHTNESS  
( ) CHECK GAS PIPING FOR LEAKS (WHERE APPLICABLE)  
( ) CHECK THAT INDOOR (EVAPORATOR) AIR FILTER IS CLEAN AND IN PLACE  
( ) VERIFY THAT UNIT INSTALLATION IS LEVEL  
( ) CHECK FAN WHEEL, AND PROPELLER FOR LOCATION IN HOUSING/ORIFICE AND SETSCREW TIGHTNESS  
III. START--UP  
ELECTRICAL  
SUPPLY VOLTAGE  
COMPRESSOR AMPS  
INDOOR (EVAPORATOR) FAN AMPS  
TEMPERATURES  
OUTDOOR (CONDENSER) AIR TEMPERATURE  
RETURN--AIR TEMPERATURE  
DB  
DB  
WB  
COOLING SUPPLY AIR  
DB  
WB  
HEAT PUMP SUPPLY AIR__________________  
GAS HEAT SUPPLY AIR  
PRESSURES  
GAS INLET PRESSURE  
IN. W.C.  
GAS MANIFOLD PRESSURE  
REFRIGERANT SUCTION  
REFRIGERANT DISCHARGE  
IN. W.C.  
PSIG, SUCTION LINE TEMP*  
PSIG, LIQUID TEMP{  
( ) VERIFY REFRIGERANT CHARGE USING CHARGING CHARTS  
GAS HEAT TEMPERATURE RISE  
TEMPERATURE RISE (See Literature) RANGE  
MEASURED TEMPERATURE RISE  
* Measured at suction inlet to compressor  
{
Measured at liquid line leaving condenser.  
Catalog No: 48EZ---08SI  
Copyright 2010 Carrier Corp. S 7310 W. Morris St. S Indianapolis, IN 46231  
Edition Date: 09/10  
Manufacturer reserves the right to change, at any time, specifications and designs without notice and without obligations.  
Replaces: 48EZ---07SI  
41  
Download from Www.Somanuals.com. All Manuals Search And Download.  

BenQ Projector MP511 User Manual
Blackberry Cell Phone 8100 Series User Manual
Black Decker Saw 381341 01 User Manual
Bosch Appliances Range HES3053U User Manual
Bosch Appliances Security Camera VIP X1600 M4S User Manual
Bosch Power Tools Cordless Drill 11536C User Manual
Boston Acoustics Stereo Amplifier GT 20 GT 222 User Manual
Brother Sewing Machine 882 C50 User Manual
Casio Cash Register TE 2200 User Manual
Casio Musical Instrument PL 40R User Manual