Greenheck Fan Make Up Air Unit VSU User Manual

Part #457831  
VSU Make-Up Air Unit  
®
Installation, Operation and Maintenance Manual  
Please read and save these instructions. Read carefully before attempting to assemble, install, operate or maintain the  
product described. Protect yourself and others by observing all safety information. Failure to comply with instructions  
could result in personal injury and/or property damage! Retain instructions for future reference.  
2. The rotation of the wheel is critical. It must be  
Model VSU  
free to rotate without striking or rubbing any  
stationary objects.  
3. Motor must be securely and adequately  
grounded.  
4. Do not spin fan wheel faster than the maximum  
cataloged fan rpm. Adjustments to fan speed  
significantly affects motor load. If the fan RPM is  
changed, the motor current should be checked  
to make sure it is not exceeding the motor  
nameplate amps.  
5. Do not allow the power cable to kink or come  
in contact with oil, grease, hot surfaces,  
or chemicals. Replace cord immediately if  
damaged.  
6. Verify that the power source is compatible with  
Optional Service  
Platform Shown  
the equipment.  
7. Never open blower access doors while the fan is  
running.  
General Safety Information  
FOR YOUR SAFETY  
Only qualified personnel should install this unit.  
Personnel should have a clear understanding of these  
instructions and should be aware of general safety  
precautions. Improper installation can result in electric  
shock, possible injury due to coming in contact with  
moving parts, as well as other potential hazards.  
Other considerations may be required if high winds  
or seismic activity are present. If more information  
is needed, contact a licensed professional engineer  
before moving forward.  
If you smell gas:  
1. Open windows.  
2. Do not touch electrical switches.  
3. Extinguish any open flame.  
4. Immediately call your gas supplier.  
FOR YOUR SAFETY  
The use and storage of gasoline or  
other flammable vapors and liquids in  
open containers in the vicinity of this  
appliance is hazardous.  
1. Follow all local electrical and safety codes, as  
well as the National Electrical Code (NEC), the  
National Fire Protection Agency (NFPA), where  
applicable. Follow the Canadian Electric Code  
(CEC) in Canada.  
WARNING  
DANGER  
Improper installation, adjustment,  
alteration, service or maintenance can  
cause property damage, injury or death.  
Read the installation, operating and  
maintenance instructions thoroughly  
before installing or servicing this  
equipment.  
Always disconnect power before working on or  
near a unit. Lock and tag the disconnect switch or  
breaker to prevent accidental power up.  
CAUTION  
When servicing the unit, motor may be hot enough  
to cause pain or injury. Allow motor to cool before  
servicing.  
Model VSU Make-Up Air Unit  
1
Table of Contents  
Installation  
Installation  
1. Filter/Stand Section  
Filter/Stand Section . . . . . . . . . . . . . . . . . . . . . .3-4  
Burner/Blower Section . . . . . . . . . . . . . . . . . . . . . 4  
Ductwork . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4  
Dimensional Data . . . . . . . . . . . . . . . . . . . . . . . . . 5  
Direct Gas Piping . . . . . . . . . . . . . . . . . . . . . . . .6-7  
Start-Up  
The unit should be mounted on a concrete slab four  
inches thick with a proper gravel drainage bed. Allow  
one foot on each side of the unit as shown in the  
Concrete Slab and Unit Footprint drawing below.  
Concrete Slab Dimensions  
Blower . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .8-9  
Direct Gas . . . . . . . . . . . . . . . . . . . . . . . . . . . .10-12  
Operation  
Electrical . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13  
Troubleshooting  
Blower . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14  
Heater . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .15-17  
Maintenance  
Housing Size  
40  
78  
A
B
C
D
E
135  
43  
54  
111  
All dimensions are shown in inches.  
Routine . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .18-19  
Fall . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19  
Reference  
Building Wall  
Approx. Stand Feet Locations  
Typical Control Center Layout . . . . . . . . . . . . . . 20  
Typical Gas Train Layout. . . . . . . . . . . . . . . . . . . 20  
Start-Up Check List . . . . . . . . . . . . . . . . . . . . . . 21  
Maintenance Log . . . . . . . . . . . . . . . . . . . . . .22-23  
Warranty . . . . . . . . . . . . . . . . . . . . . . . . .Backcover  
Concrete Slab  
D
A
E
12  
12  
C
B
Concrete Slab and Unit Footprint  
The filter section ships inside the stand (see drawing  
on next page). After the unit is set on the slab, it can  
be anchored through the stand feet. The unit footprint  
of the unit is shown above.  
Greenheck recommends having a three foot clearance  
on the controls side and a two foot clearance on the  
other three sides of the unit for serviceability.  
The following statement pertains to direct gas units  
only. When ordered with insulation, this unit has a  
zero-inch clearance tolerance to any combustibles,  
on all sides and top. Without insulation, the clearance  
tolerance is six inches.  
Model VSU Make-Up Air  
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4. Complete Installation  
A typical horizontal discharge installation is shown.  
Gas and/or electrical lines can be connected at this  
time.  
Installation continued  
2. Burner/Blower Section  
Use a crane and a spreader bar hooked to the factory  
lifting lugs (shown below) to lift and center the unit  
onto the filter stand section. The sections can be  
caulked together, but it is not needed with the water  
kickouts provided with this section.  
For upblast units, a duct elbow may be needed to  
turn the ductwork into the building. Follow proper  
ductwork methods recommended by AMCA to make  
this elbow to minimize duct losses.  
3. Install Ductwork  
This table shows the duct sizes and straight lengths  
recommended for optimal performance (AMCA  
Publication 201-90). Using duct sizes less than  
recommended will affect fan performance. Good  
duct installation practices should be followed for  
the remaining ductwork. See the drawings in the  
Dimensional Data section for duct locations.  
Recommended Supply Ductwork Sizes  
VSU  
Blower Size  
Duct  
Size  
Straight Duct  
Length  
220  
68 x 26 inches  
117 inches  
Model VSU Make-Up Air  
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Dimensional Data  
Upblast Discharge  
Elevation View  
F
H
K
J
Lifting Lugs  
Electrical Controls  
Gas Controls*  
C
A
E
24^  
B
*Direct Gas units only  
^Standard factory clearance. Additional stand heights are available from the factory.  
Unit Dimensional Data  
Blower Dimensional Data  
Unit Weight  
Housing  
Size  
Blower  
Size  
A
B
C
E
Filters  
F
H
J
K
Blower/Heater*  
Stand/Filter  
40  
111  
54  
95  
144  
(20) 20x25  
220  
26  
20  
68  
12  
2000 lbs.  
700 lbs.  
All dimensions are shown in inches.  
* Weights will vary with blower and horsepower.  
Model VSU Make-Up Air  
5
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1. Determine the Supply Gas  
Requirements  
Installation of Direct Gas Piping  
The unit’s direct gas nameplate states the requirements  
for the gas being supplied to the unit. The direct gas  
nameplate is located on the outside of the unit on the  
control center side.  
Minimum gas pressure for  
maximum output  
IMPORTANT  
All gas piping must be installed in accordance  
with the latest edition of the National Fuel Gas  
Code ANSI/Z223.1 and any local codes that may  
apply. In Canada, the equipment shall be installed  
in accordance with the Installation Code for Gas  
Burning Appliances and Equipment (CGA B149)  
and Provincial Regulations for the class. Authorities  
having jurisdiction should be consulted before  
installations are made.  
MAX BTU/HR  
BTU/H MAX  
MIN BTU/HR  
BTU/H MIN  
NORMAL MANIFOLD  
PRESSURE  
PRESSION DÕADMISSION  
NORMALE  
MIN GAS PRESSURE  
FOR MAX OUTPUT  
PRESSION DE GAZ MIN  
POUR PUISSANCE MAX  
“ W.C.  
“ W.C.  
“ W.C.  
“ W.C.  
“ W.C.  
WARNING  
MIN GAS  
PRESSURE  
PRESSION DE GAZ  
MAX GAS  
PRESSURE  
PRESSION DE GAZ  
MAX  
All components of this or any other gas-fired heating  
unit must be leak tested prior to placing the unit  
into operation. A soap and water solution should be  
used to perform this test. NEVER test for gas leaks  
with an open flame.  
MIN BURNER  
MAX BURNER  
PRESSURE DROP  
PERTE MIN DE PRESSION  
DANS LE BRULEUR  
PRESSURE DROP  
PERTE MAX DE PRESSION  
DANS LE BRULEUR  
PSI  
TYPE OF GAS  
NATURE DU GAZ  
DESIGN T  
T NORMALE  
F
WARNING  
EQUIPPED FOR  
CONCU POUR  
AGAINST  
CONTE  
EXTERNAL STATIC PRESSURE  
SCFM  
“ W.C.  
If pressure testing in excess of 1/2 psig (3.5 kPa),  
the heater and manual shutoff valve must be  
disconnected from the supply gas line.  
PRESSION STATIQUE EXTERIEURE  
Type of gas  
Maximum gas pressure  
WARNING  
Direct Gas Nameplate  
If pressure testing at or below 1/2 psig (3.5 kPa), the  
heater must be isolated from the supply gas line by  
closing its manual shutoff valve.  
2. Install Additional Regulator if Required  
When the supply gas pressure exceeds the maximum  
gas pressure shown on the direct gas nameplate, an  
additional regulator (by others) is required to reduce  
the pressure. The regulator must have a listed leak  
limiting device or it must be vented to the outdoors.  
IMPORTANT  
All piping should be clean and free of any foreign  
matter. Foreign material entering the gas train can  
damage the valves, regulators and burner.  
IMPORTANT  
NOTE  
Do NOT connect the unit to gas types other than  
what is specified and do NOT connect the unit to  
gas pressures that are outside of the pressure range  
shown on the label.  
The regulator located inside the unit is used to  
adjust the unit’s maximum output temperature.  
3. Connect the Supply Gas Line  
NOTE  
A manual shut off valve (gas cock), 1/8 in. plugged  
test port and 6 in. drip leg must be installed prior to  
the gas train. The valve and the test port must be  
accessible for the connection of a test gauge. Supply  
gas connections must be made by a qualified installer  
and are not furnished by Greenheck.  
When connecting the gas supply, the length of the  
run must be considered in determining the pipe size  
to avoid excessive pressure drop. Refer to a Gas  
Engineer’s Handbook for gas pipe capacities.  
To  
Controls  
Gas Cock  
Ground Joint Union  
From  
Gas  
Supply  
1/8 in. Plugged Ta p  
6 in. Trap  
Supply Gas Line  
Model VSU Make-Up Air  
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4. Pipe the Optional Vent Line  
If an optional vent line is located between the safety  
shutoff valves it must be piped to the outdoors.  
WARNING  
Reference the National Fuel Gas Code for additional  
vent line requirements.  
Vent Line Solenoid  
To Outdoors  
To Burner  
From Supply  
Safety  
Shut-off Valves  
Optional Vent Line  
5. Test the System for Leaks  
Check both the supply lines and the factory piping for  
leaks. Apply a soap and water solution to all piping  
and watch for bubbling which indicates a leak.  
WARNING  
NEVER test for a gas leak with an open flame.  
NOTE  
The factory piping has been checked for leaks, but  
should be rechecked due to shipping and installation.  
Model VSU Make-Up Air  
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2. Check the Blower Rotation  
Open the blower access door  
and run the blower momentarily  
to determine the rotation.  
Start-Up - Blower  
Refer to the Start-Up Checklist in the Reference  
section before proceeding further!  
Arrows are placed on the  
Pre Start-Up Check  
blower scroll to indicate the  
proper direction or reference  
the example shown to the right.  
Rotate the fan wheel by hand and make sure no parts  
are rubbing. Check the V-belt drive for proper alignment  
and tension (a guide for proper belt tension and  
alignment is provided in the Belt Maintenance section).  
Check fasteners, set screws and locking collars on the  
fan, bearings, drive, motor base, and accessories for  
tightness.  
Blower  
Housing  
Blower Rotation  
NOTE  
To reverse the rotation on three phase units,  
disconnect and lock-out the power, then  
interchange any two power leads.  
WARNING  
Disconnect and lock-out all power and gas before  
performing any maintenance or service to the unit.  
Failure to due so could result in serious injury or  
death and damage to equipment.  
NOTE  
To reverse the rotation on single phase units,  
disconnect and lock-out the power, then rewire the  
motor per the manufacturer’s instructions.  
IMPORTANT  
SPECIAL EQUIPMENT REQUIRED  
If the blower is rotating in the wrong direction, the  
unit will move some air, but will not perform as  
designed. Be sure to perform a visual inspection to  
guarantee the correct blower rotation.  
Required and recommended tools. Equivalent  
products may be used.  
Manufacturer:  
Model:  
Phone:  
Fluke  
177  
1-800-44-FLUKE  
Voltage &  
Amperage  
Meter  
3. Check for Vibration  
Check for unusual noise, vibration or overheating of  
the bearings. Reference the Troubleshooting section  
for corrective actions.  
Manufacturer:  
Model:  
Phone:  
Fluke  
50  
1-800-44-FLUKE  
Thermometer  
IMPORTANT  
Manufacturer:  
Model:  
Fluke  
116  
1-800-44-FLUKE  
Excessive vibration may be experienced during  
the initial start-up. Left unchecked, it can cause a  
multitude of problems including structural and/or  
component failure.  
Micro Amp  
Meter  
Phone:  
Manufacturer:  
Model:  
Dwyer  
Slack Tube  
1-219-897-8000  
IMPORTANT  
U-Tube  
Manometer  
Phone:  
Generally, fan vibration and noise is transmitted  
to other parts of the building by the ductwork. To  
minimize this undesirable effect, the use of heavy  
canvas duct connectors is recommended.  
Manufacturer: Monarch  
Model:  
Phone:  
Pocket Tach 100  
1-800-999-3390  
Tachometer  
4. Motor Check  
Measure the motor’s voltage, amps and RPM.  
Compare to the specifications. Motor amps can be  
reduced by lowering the motor RPM or increasing  
system static pressure.  
WARNING  
Check the housing, blower, and ductwork for any  
foreign objects before running the blower.  
1. Check the Voltage  
Before starting the unit, compare the supplied voltage,  
hertz, and phase with the unit and motor’s nameplate  
information.  
Voltage, Hertz, Phase  
VOLTS  
HZ  
EXH HP  
MOP  
PH  
SUP HP  
MCA  
Electrical Nameplate  
Model VSU Make-Up Air  
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5. Air Volume Measurement & Check  
Measure the unit’s air volume (cfm) and compare it with  
it’s rated air volume. If the measured air volume is off,  
adjust the fan’s RPM by changing/adjusting the drive.  
NOTE  
The most accurate way to measure the air volume is  
by using a pitot traverse method downstream of the  
blower. Other methods can be used, but should be  
proven and accurate.  
IMPORTANT  
Changing the air volume can significantly increase  
the motor’s amps. If the air volume is changed,  
the motor’s amps must be checked to prevent  
overloading the motor.  
NOTE  
To ensure accuracy, the dampers are to be open  
when measuring the air volume.  
6. Set-up Optional Components  
Adjust the settings on the optional components. See  
the Control Center Layout in the Reference section for  
location of optional components.  
• Heating Inlet Air Sensor  
Typical setting: 60-70ºF  
Model VSU Make-Up Air  
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3. Set the Burner Air Pressure Differential  
With the fan running and discharging 70ºF (21ºC) air,  
connect a U-Tube manometer to the outer sensing  
probes (see below) and measure the static pressure  
across the burner.  
Start-Up Direct Gas  
IMPORTANT  
For proper unit function and safety, follow the start-  
up procedure in the exact order that it is presented.  
Outer Sensing Probes  
IMPORTANT  
This start-up should begin after all of the installation  
procedures and the blower start-up have been  
completed.  
7
0.625 - 0.675 in. wc  
1. Check the Supply Gas Pressure  
Check the supply gas pressure and compare it with  
the unit’s nameplate pressure requirements. Adjust  
the supply regulator as needed until the supply gas  
pressure is within the specified range. The direct gas  
nameplate is located on the outside of the unit on the  
control center side.  
6
U-Tube  
Manometer  
Measuring the Pressure Drop  
Minimum and maximum gas  
pressures for maximum output  
The proper static pressure should be between 0.625  
and 0.675 inches wc (155.68 and 168.64 Pa). If  
needed, evenly adjust the baffles on both sides of the  
burner, keeping the burner centered in the opening  
until the required pressure is obtained.  
MAX BTU/HR  
BTU/H MAX  
MIN BTU/HR  
BTU/H MIN  
NORMAL MANIFOLD  
PRESSURE  
PRESSION DÕADMISSION  
NORMALE  
MIN GAS PRESSURE  
FOR MAX OUTPUT  
PRESSION DE GAZ MIN  
POUR PUISSANCE MAX  
“ W.C.  
“ W.C.  
“ W.C.  
“ W.C.  
“ W.C.  
MIN GAS  
PRESSURE  
PRESSION DE GAZ  
MAX GAS  
PRESSURE  
PRESSION DE GAZ  
MAX  
Burner  
MIN BURNER  
MAX BURNER  
PRESSURE DROP  
PERTE MIN DE PRESSION  
DANS LE BRULEUR  
PRESSURE DROP  
PERTE MAX DE PRESSION  
DANS LE BRULEUR  
PSI  
Adjustable  
Baffle  
Adjustable  
Baffle  
TYPE OF GAS  
NATURE DU GAZ  
DESIGN T  
T NORMALE  
F
Airflow  
Airflow  
EQUIPPED FOR  
CONCU POUR  
AGAINST  
CONTE  
EXTERNAL STATIC PRESSURE  
“ W.C.  
SCFM  
PRESSION STATIQUE EXTERIEURE  
Type of gas  
Burner and Baffles  
Direct Gas Nameplate  
NOTE  
2. Check the Pilot Gas Pressure  
The pressure drop was set at the factory and may  
not need adjustment.  
Check the pilot gas pressure. The recommended  
gas pressure is 3 in. wc. Adjust the pilot regulator as  
needed. See the Gas Train Layout in the Reference  
section for the location of the pilot pressure test port  
and pilot regulator.  
NOTE  
When required pressure is obtained, be sure to  
reconnect the outer sensing probes.  
IMPORTANT  
IMPORTANT  
This process may need to be repeated until the  
proper pressure is achieved. This adjustment  
will change the air quantity delivered by the unit  
and therefore the air quantity delivered should be  
rechecked. Refer to the Blower Start-Up section.  
Proper air velocity over the burner is critical on direct  
fired gas units. If the air velocity is not within the unit  
specifications, the unit will not operate efficiently,  
may have sporadic shutdowns, and may produce  
excessive carbon monoxide (CO) or other gases.  
NOTE  
To increase the static pressure decrease the  
opening. To decrease the static pressure increase  
the opening.  
Model VSU Make-Up Air  
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4. Set the Maximum Firing Rate  
Monitor the unit’s actual temperature rise by placing  
a thermocouple in the unit’s inlet and a second in the  
discharge, three duct diameters downstream of the  
burner.  
Regulators and Modulating Valves  
Remove one wire to  
Remove cap to access  
maximum firing rate  
adjustment  
send the unit to the  
minimum firing rate  
Send the unit to maximum fire by disconnecting and  
isolating the wire connected to Terminal 4 on the  
Maxitrol 14.  
While monitoring the units temperature rise, set the  
maximum firing rate by adjusting the regulator until the  
designed temperature rise is achieved. After setting the  
maximum firing rate, reconnect the wire to the amplifier.  
Minimum  
firing rate  
adjustment  
NOTE  
Separate Regulator and Modulating Valves  
Do not set the burner maximum firing rate based on gas  
pressure. It should be set based on the unit’s designed  
temperature rise shown on the direct gas label.  
5. Set the Minimum Firing Rate  
Disconnect and isolate one of the wires running to  
the modulating valve to send the unit to its minimum  
firing rate. Set the minimum firing rate by adjusting the  
needle valve shown above.  
MIN GAS  
MAX GAS  
PRESSURE  
PRESSION DE GAZ  
PRESSURE  
PRESSION DE GAZ  
MAX  
“ W.C.  
“ W.C.  
“ W.C.  
After setting the minimum firing rate, shut off the  
pilot to ensure that the flame safeguard can still read  
the main flame signal. Reconnect the wire to the  
modulation valve and open the pilot shut-off valve.  
MIN BURNER  
MAX BURNER  
PRESSURE DROP  
PERTE MIN DE PRESSION  
DANS LE BRULEUR  
PRESSURE DROP  
PERTE MAX DE PRESSION  
DANS LE BRULEUR  
PSI  
TYPE OF GAS  
NATURE DU GAZ  
DESIGN T  
T NORMALE  
F
EQUIPPED FOR  
CONCU POUR  
AGAINST  
CONTE  
EXTERNAL STATIC PRESSURE  
NOTE  
“ W.C.  
SCFM  
PRESSION STATIQUE EXTERIEURE  
The minimum setting for the maximum firing rate  
may be higher than required. This is acceptable. The  
burner will modulate as needed.  
Direct Gas Nameplate  
IMPORTANT  
Maxitrol Series 14 — 7 terminals  
The proper minimum firing rate setting results in a  
small ribbon of continuous flame which covers the  
flame road and runs across the entire burner.  
Remove the wire from terminal #4 to  
send the unit to maximum fire  
IMPORTANT  
Do not allow the disconnected wire to come in  
contact with a potential ground. Damage to the  
amplifier or transformer could result.  
NOTE  
Gas trains are equipped with separate regulators  
and modulating valves.  
Low fire time delay setting (75% of maximum)  
NOTE  
IMPORTANT  
Adjusting the maximum and minimum firing rate  
requires the inlet air sensor to be set higher than the  
outdoor air temperature in order to start the burner(s).  
Once high and low fire have been set, the inlet air  
sensor should be set to the desired temperature.  
Setting the maximum firing rate during mild weather  
conditions may cause the high limit to trip out during  
extreme conditions requiring manual resetting.  
NOTE  
NOTE  
Gas trains are equipped with either separate  
regulators and modulating valves or with a  
combined modulating valve.  
Counterclockwise rotation increases the minimum  
fire rate setting, clockwise rotation decreases the  
setting.  
NOTE  
Clockwise rotation increases the temperature  
rise, counterclockwise rotation decreases the  
temperature rise.  
Model VSU Make-Up Air  
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6. Set the Unit’s Operating Temperature  
Set the operating temperature. The operating  
temperature setting depends on which Maxitrol controller  
is used.  
Maxitrol Series 14  
The Maxitrol Series 14 should be set to the desired  
discharge temperature. The temperature selector is built  
into the amplifier.  
Set the discharge temperature  
Typical: 65ºF  
Series 14 Discharge Temperature Setting  
7. Flame Signal Check  
To measure the flame signal connect a standard DC  
voltmeter to the flame amplifier test jacks + and -  
(com) as shown to  
the right. The flame  
signal should be  
above 1.25 VDC and  
steady.  
Check the flame  
signal with the  
burner at pilot only,  
minimum fire, mid  
fire and high fire.  
DC Voltmeter and  
Flame Amplifier  
IMPORTANT  
If the flame signal is not above 1.25 VDC and steady,  
consult the troubleshooting section.  
Model VSU Make-Up Air  
12  
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Operation - Electrical  
Electrical Sequence  
Direct Gas Burner Sequence  
1. Supply Fan Contact (S2) Closed  
1. Supply Fan Contact Closed  
• Power passes to damper which opens  
• Power passes to the supply fan and heat switch  
• When damper is fully opened, damper relay  
(D1) is energized an optional N.O. damper limit  
switch (DL1) closes  
2. Heat Contact Closed  
• Power passes to the heat relay then to the  
Flame Safeguard  
• Power passes through a N.C. fault contact on  
soft starter (PST(FAULT))  
• Power passes to and energizes supply fan relay  
(RI)  
3. Flame Safeguard (FSG) Sequence  
• Checks for proper airflow  
• Verifies no flame present at burner  
• Initiates 10 second prepurge  
• Sends power to open pilot gas valve (V1) and  
energizes the spark generator (SG) (clicking of  
the spark generator may be heard)  
Tries for up to 10 seconds to light pilot and  
confirm flame  
• Powers the main gas valves open  
• Shuts down spark generator  
• Continuously monitors the flame and airflow  
• Supply fan starts  
2. Heat Contact (S4) Closed  
• Power passes to N.O. fan relay which is  
energized and closed  
• Power passes to inlet air sensor contact (TS)  
which is energized and closed if the inlet air  
temperature is below the set point  
• Power passes to and energizes the heat relay  
(RH)  
• N.O. heat relay contact (RH) closes  
• Power passes to and energizes terminal 5 of the  
• Performs self-diagnostic check every five  
seconds  
Flame Safeguard (FSG).  
• Power passes to N.C. high limit control contact  
(HLC) which is closed if temperature has  
remained below the high limit set point  
• Power passes to terminal 6 of the Flame  
Safeguard (FSG)  
• Flame Safeguard (FSG) begins direct gas burner  
sequence (see Direct Gas Burner sequence)  
Model VSU Make-Up Air  
13  
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Troubleshooting  
Blower Does Not Operate  
No  
115 VAC between  
Check Main Voltage  
(See Blower Start-Up Step #1)  
Main Disconnect (DS1) Off  
(Turn Main Disconnect DS1 On)  
Primary Fuses Blown  
terminals 102 and 101?  
Yes  
(Replace Fuses)  
Main Transformer Defective  
(Replace Transformer)  
No  
No  
No  
24 VAC between  
terminals R and X?  
Main Transformer Defective  
Yes  
(Replace Transformer)  
24 VAC between  
terminals G and X?  
Supply Switch (S2) Off  
(Turn Supply Switch (S2) On)  
Yes  
24 VAC between  
terminals 7 and X?  
Yes  
Damper Limit Switch (DL1) Holding  
(Wait for actuator to open fully or adjust limit switch)  
Broken Fan Belt  
(Replace - Reference Maintenance section)  
Defective motor or capacitor  
(Repair/Replace)  
Blown Motor Fuse  
(Replace)  
One or more legs of 3 phase is out  
(Restore missing legs)  
At this time the supply should be energized., passing  
power to the supply motor and the blower should start.  
Model VSU Make-Up Air  
14  
®
Troubleshooting  
Heater Does Not Operate  
Does not attempt to light (No visible spark)  
No  
No  
No  
24 VAC between  
terminals W1 and X?  
Heat Switch (S4) Off  
(Turn Heat Switch (S4) On)  
Heat Switch Not Wired  
(Wire Heat Switch (S4))  
Yes  
115 VAC between  
terminals 102 and 101?  
Primary Fuses Blown  
(Replace Fuses)  
Main Transformer (TR4) Defective  
(Replace Transformer)  
Yes  
115 VAC between  
terminals 103 and 101?  
Inlet Air Sensor (TS) Holding  
(Adjust TS setting — Reference Blower Start-Up Step #6)  
Heat Relay (RH) Defective  
Yes  
(Replace Heat Relay (RH))  
The power light on the flame safeguard should  
blink approximately every 5 seconds as it  
performs a self-diagnostics check.  
No  
No  
115 VAC between  
terminals 104 and 101?  
High Limit (HLC) Tripped  
(Reset/Replace High Limit (HLC))  
(Check on cause of control loss)  
Yes  
Continuity between  
terminals 107 and 108?  
Airflow Switch (PS) Holding for Proper Airflow  
(Correct airflow across burner)  
Yes  
(Reference Direct Gas Start-Up Step #3)  
At this time the heater should attempt to light.  
(The pilot light on the flame safeguard should illuminate).  
Model VSU Make-Up Air  
15  
®
Troubleshooting  
Heater Does Not Operate  
Attempts to light, but no pilot (visible spark)  
Check inlet gas pressure.  
Note: The minimum and maximum gas pressures  
for your unit are shown on the direct gas label.  
(Reference Direct Gas Start-Up – Step #1)  
(Direct Gas Start-Up Step #1)  
Yes  
Gas pressure between the  
No  
minimum and maximum shown  
on the direct gas label?  
Correct gas pressure  
(Reference Direct Gas Start-Up – Step #1)  
Yes  
Air in the gas line?  
Purge gas line  
(Verify gas at the pilot)  
No  
Check for proper airflow  
(Direct Gas Start-Up Step #3)  
Note: The airflow may satisfy the airflow switch,  
but may make lighting the pilot difficult. Adjust the  
pressure drop across the burner between 0.625 and  
0.675 in. wc shown in Direct Gas Start-Up – Step #3  
Yes  
Pressure drop across the burner  
between 0.625 and 0.675 in. wc?  
No  
Adjust burner baffles  
(Reference Direct Gas Start-Up – Step #3)  
Yes  
Crossed flame and spark wires  
(Uncross wires and reconnect)  
Incorrect spark plug gap  
(Set spark plug gap to 0.062 in.)  
Defective spark plug  
No  
Proper spark?  
Yes  
(Replace spark plug)  
Check for proper pilot pressure  
(Direct Gas Start-Up Step #2)  
Note: A high pilot pressure will make lighting more  
difficult. Lower the pilot pressure in increments  
until the unit lights. Then set the pilot per the  
instruction in Direct Gas Start-Up – Step. #2  
No  
No  
Pilot pressure correct?  
Adjust the pilot pressure  
(Reference Direct Gas Start-Up – Step #2)  
Yes  
With proper airflow, gas pressure and spark,  
the unit should light.  
If problems remain, consult the factory  
Model VSU Make-Up Air  
16  
®
Troubleshooting  
Heater Does Not Operate  
Visible pilot  
Measure the flame signal  
when there is a visible pilot  
Note: The flame signal should be steady and  
above 1.25 VDC with a visible pilot.  
(Reference Direct Gas Start-Up – Step #7)  
Flame signal greater  
than 1.25 VDC  
No  
Unit is not grounded  
(Properly ground unit)  
Flame rod is grounding out  
(Adjust the flame rod to avoid contact with the burner or the unit)  
Cracked porcelain on flame rod  
(Replace flame rod)  
Yes  
Check for proper airflow  
(Direct Gas Start-Up Step #3)  
Note: When the pressure is low or marginal and the unit  
begins heating, the air density will change. This can cause  
the pressure to drop below the minimum setting. Also, low  
airflow can cause the flame to walk out of the burner and  
away from the flame sensor, causing the unit to recycle.  
Pressure drop across the burner  
between 0.625 and 0.675 in. wc?  
No  
Adjust burner baffles  
(Reference Direct Gas Start-Up – Step #3)  
Yes  
Check the minimum firing rate  
(Direct Gas Start-Up Step #4  
No  
No  
Is the minimum firing rate  
set correctly?  
Adjust the minimum firing rate  
(Reference Direct Gas Start-Up – Step #4)  
Yes  
Does the flame signal  
remain constant?  
If the signal slowly drops off, typically the airflow is too low  
(Reference Blower Start-Up – Step #4)  
If it suddenly drops to zero, the flame rod is grounding out  
(Adjust the flame rod to avoid contact with the burner or the unit)  
Yes  
If the flame signal is above 1.25 VDC and constant,  
the main gas valves will remain open until the call  
for heat is interrupted or the unit is shut down.  
Model VSU Make-Up Air  
17  
®
Maintenance - Routine  
Motors  
CAUTION  
Motor maintenance is generally limited to cleaning  
and lubrication (where applicable).  
Cleaning should be limited to exterior surfaces only.  
Removing dust and grease build-up on the motor  
assures proper motor cooling.  
Motors supplied with grease fittings should be  
greased in accordance with the manufacturer’s  
recommendations.  
Lock-out the gas and the electrical power to the  
unit before performing any maintenance or service  
operations to this unit.  
V-Belt Drives  
V-belt drives must be checked on a regular basis for  
wear, tension, alignment, and dirt accumulation.  
Check the tension by measuring the deflection in the  
belt as shown below.  
IMPORTANT  
Check the alignment by using a straight edge across  
both sheaves as shown below.  
Do not allow water or solvents to enter the motor  
or bearings. Motors and bearings should never be  
sprayed with steam, water or solvents.  
IMPORTANT  
IMPORTANT  
Premature or frequent belt failures can be caused by  
improper belt tension or misaligned sheaves.  
Greasing motors is only intended when fittings are  
provided. Many motors are permanently lubricated,  
requiring no additional lubrication.  
• Abnormally high belt tension or drive misalignment  
will cause excessive bearing loads and may result  
in failure of the fan and/or motor bearings.  
• Abnormally low belt tension will cause squealing  
on start-up, excessive belt flutter, slippage, and  
overheated sheaves.  
Wheels  
Wheels require little attention when moving clean air.  
Occasionally oil and dust may accumulate on the wheel  
causing imbalance. When this occurs the wheel and  
housing should be cleaned to assure proper operation.  
IMPORTANT  
Do not pry belts on or off the sheave. Loosen belt  
tension until belts can be removed by simply lifting  
the belts off the sheaves.  
Filters  
IMPORTANT  
Filter maintenance is generally limited to cleaning and  
replacement.  
When replacing V-belts on multiple groove drives,  
all belts should be changed to provide uniform drive  
loading.  
Aluminum mesh filters can be washed in warm soapy  
water.  
An adhesive spray can be added to aluminum mesh  
filters to increase their efficiency.  
IMPORTANT  
Do not install new belts on worn sheaves. If the  
sheaves have grooves worn in them, they must be  
replaced before new belts are installed.  
IMPORTANT  
When reinstalling filters, be sure to install them  
with the airflow in the correct direction. An airflow  
direction arrow is located on the side of the filters.  
Belt Span  
Deflection =  
64  
IMPORTANT  
Replacement filters should be from the same  
manufacturer and the same size as the original  
filters provided with the unit.  
Belt Span  
Belt Tension  
Drive Alignment  
Model VSU Make-Up Air  
18  
®
Maintenance - Fall  
Bearings  
Start-Up  
Repeat the Blower Start-Up Step #5 and Direct Gas Start-  
Up Steps #1 through #4. This will ensure that the gas and  
air are set properly before the heating season begins and  
should lead to trouble free operation all winter.  
The bearings for Greenheck fans are carefully selected  
to match the maximum load and operating conditions  
of the specific class, arrangement and fan size. The  
instructions provided in this manual and those provided  
by the bearing manufacturer will minimize any bearing  
problems.  
High Limit  
The high limit switch may have tripped over the  
summer; it should be checked and reset if necessary.  
IMPORTANT  
Burner  
Lubricate bearings prior to periods of extended  
shutdowns or storage and rotate shaft monthly to  
aid in corrosion prevention. If the fan is stored more  
than three months, purge the bearings with new  
grease prior to start-up.  
Inspect the burner for accumulation of scales on both  
the upstream and downstream sides of the mixing  
plates. Any scaling or foreign material should be  
removed with a wire brush.  
Visually check that all holes in the mixing plates are clear.  
If any burner ports are plugged (even partially), clear  
them with a piece of wire or another appropriate tool.  
Recommended Bearing Lubrication Schedule (in Months*)  
Bearing Bore Size (inches)  
Fan  
RPM  
1
2  
-1  
118 -112  
158 - 178 11516 -2316  
2716 -3  
3
Replace or tighten any loose or missing fasteners on  
the mixing plates. Always use zinc plated or stainless  
steel fasteners.  
750  
6
5
4
3
*Suggested initial greasing interval is based on 12 hour per  
day operation and 150°F maximum housing temperature.  
For continuous (24 hour) operation, decrease greasing  
interval by 50%  
Inspect and clean the flame and spark rod. Occasional  
replacement of the flame rod and spark rod may be  
necessary to ensure optimum unit performance.  
• If extended grease lines are present, relubricate while in  
operation, only without endangering personnel.  
WARNING  
• For ball bearings (operating) relubricate until clean grease  
is seen purging at the seals. Be sure not to unseat the seal  
by over lubricating.  
• For ball bearings (idle) add 1-2 shots of grease up to  
2 inch bore size, and 4-5 shots above 2 inch bore sizes  
with a hand grease gun.  
• For roller bearings add 4 shots of grease up to 2 inch bore  
size, and 8 shots for 2-5 inch bore size with a hand grease  
gun.  
Do not enlarge burner ports when clearing a  
blockage, performance could be affected.  
NOTE  
Flame rods can last many years, but because of  
thermal expansion of the porcelain, flame rods can  
fail over time.  
• Adjust relubrication frequency based on condition of  
purged grease.  
• A high quality lithium based grease conforming to NLGI  
Grade 2 consistency, such as those listed here:  
Mobil 532  
Mobilux #2  
Texaco Multifak #2  
Texaco Premium #2 Exxon Unirex #2  
B Shell Alavania #2  
Model VSU Make-Up Air  
19  
®
Reference  
Typical Control Center Layout  
1
5
7
2
3
4
6
12  
8
9
10  
11  
1. Spark Generator  
7. Motor Fuses  
2. Temperature Selector  
3. Amplifier  
4. 24V Transformer  
5. 120V Transformer  
6. Transformer Fuses  
8. Heating Inlet Air Switch  
9. Flame Safeguard  
10. High Limit Switch  
11. Disconnect  
12. Soft Start  
Typical Gas Train Layout  
High/Low  
Gas Pressure  
Airflow Switch*  
View Port  
Pilot Solenoid  
Valve  
Modulating  
Valve  
Pilot Regulator  
Manual Shutoff*  
Hand  
Valve  
Gas Supply  
Connection  
Fluid Valve  
*Two are provided on Canadian units.  
Model VSU Make-Up Air  
20  
®
Reference  
Start-Up Checklist  
Start-Up Direct Gas refer to Direct Gas Start-  
Up section for further detail.  
Unit Model Number _______________________________  
(e.g. VSU-220-H40-UB)  
o Check supply gas pressure  
________ Maximum  
________ Minimum  
Unit Serial Number _______________________________  
(e.g. 04c99999 or 10111000)  
Start-Up Date  
_______________________________  
________ Actual  
Start-Up Personnel Name__________________________  
Start-Up Company _______________________________  
o Check Pilot Gas Pressure  
________ Actual Setting  
Typical 3.0 inch wc  
Phone Number  
_______________________________  
o Set optional High Gas Pressure Switch  
________ Actual Setting  
Typical 8.0 inch wc  
Pre Start-Up Checklist check boxes as items  
are completed.  
o Check tightness of all factory wiring connections  
o Verify control wiring wire gauge  
o Hand-rotate blower to verify free rotation  
o Verify supply voltage to the main disconnect  
o Verify the supply gas pressure  
o Set optional Low Gas Pressure Switch  
________ Actual Setting  
Typical 3.0 inch wc  
o Set Burner Pressure Differential  
________ Actual Setting  
Typical 0.65 inch wc  
o Set the maximum firing rate  
________ temp rise  
o Verify remote controls wiring  
Start-Up Blower Checklist refer to Blower  
Start-Up section for further detail.  
o Check line voltage  
L1-L2 __________  
L2-L3 __________  
L1-L3 __________  
o Set the minimum firing rate  
________ check  
o Check blower rotation  
o Check for vibration  
o Supply fan RPM  
o Motor nameplate amps  
o Actual motor amps  
o Actual CFM delivered  
o Set the unit’s operating temperature  
________ ºF  
_________ RPM  
_________ Amps  
_________ Amps  
_________ CFM  
Optional Accessories refer to Blower Start-Up  
section, Step #6 for further detail.  
o Heating Inlet Air Sensor  
________ Actual Setting  
Typical setting 60º-70ºF  
Model VSU Make-Up Air  
21  
®
Maintenance Log  
Date __________________ Time _____________ AM/PM  
Notes:___________________________________________  
_________________________________________________  
_________________________________________________  
_________________________________________________  
_________________________________________________  
Date __________________ Time _____________ AM/PM  
Notes:___________________________________________  
_________________________________________________  
_________________________________________________  
_________________________________________________  
_________________________________________________  
Date __________________ Time _____________ AM/PM  
Notes:___________________________________________  
_________________________________________________  
_________________________________________________  
_________________________________________________  
_________________________________________________  
Date __________________ Time _____________ AM/PM  
Notes:___________________________________________  
_________________________________________________  
_________________________________________________  
_________________________________________________  
_________________________________________________  
Date __________________ Time _____________ AM/PM  
Notes:___________________________________________  
_________________________________________________  
_________________________________________________  
_________________________________________________  
_________________________________________________  
Date __________________ Time _____________ AM/PM  
Notes:___________________________________________  
_________________________________________________  
_________________________________________________  
_________________________________________________  
_________________________________________________  
Date __________________ Time _____________ AM/PM  
Notes:___________________________________________  
_________________________________________________  
_________________________________________________  
_________________________________________________  
_________________________________________________  
Date __________________ Time _____________ AM/PM  
Notes:___________________________________________  
_________________________________________________  
_________________________________________________  
_________________________________________________  
_________________________________________________  
Date __________________ Time _____________ AM/PM  
Notes:___________________________________________  
_________________________________________________  
_________________________________________________  
_________________________________________________  
_________________________________________________  
Date __________________ Time _____________ AM/PM  
Notes:___________________________________________  
_________________________________________________  
_________________________________________________  
_________________________________________________  
_________________________________________________  
Date __________________ Time _____________ AM/PM  
Notes:___________________________________________  
_________________________________________________  
_________________________________________________  
_________________________________________________  
_________________________________________________  
Date __________________ Time _____________ AM/PM  
Notes:___________________________________________  
_________________________________________________  
_________________________________________________  
_________________________________________________  
_________________________________________________  
Model VSU Make-Up Air  
22  
®
Maintenance Log  
Date __________________ Time _____________ AM/PM  
Notes:___________________________________________  
_________________________________________________  
_________________________________________________  
_________________________________________________  
_________________________________________________  
Date __________________ Time _____________ AM/PM  
Notes:___________________________________________  
_________________________________________________  
_________________________________________________  
_________________________________________________  
_________________________________________________  
Date __________________ Time _____________ AM/PM  
Notes:___________________________________________  
_________________________________________________  
_________________________________________________  
_________________________________________________  
_________________________________________________  
Date __________________ Time _____________ AM/PM  
Notes:___________________________________________  
_________________________________________________  
_________________________________________________  
_________________________________________________  
_________________________________________________  
Date __________________ Time _____________ AM/PM  
Notes:___________________________________________  
_________________________________________________  
_________________________________________________  
_________________________________________________  
_________________________________________________  
Date __________________ Time _____________ AM/PM  
Notes:___________________________________________  
_________________________________________________  
_________________________________________________  
_________________________________________________  
_________________________________________________  
Date __________________ Time _____________ AM/PM  
Notes:___________________________________________  
_________________________________________________  
_________________________________________________  
_________________________________________________  
_________________________________________________  
Date __________________ Time _____________ AM/PM  
Notes:___________________________________________  
_________________________________________________  
_________________________________________________  
_________________________________________________  
_________________________________________________  
Date __________________ Time _____________ AM/PM  
Notes:___________________________________________  
_________________________________________________  
_________________________________________________  
_________________________________________________  
_________________________________________________  
Date __________________ Time _____________ AM/PM  
Notes:___________________________________________  
_________________________________________________  
_________________________________________________  
_________________________________________________  
_________________________________________________  
Date __________________ Time _____________ AM/PM  
Notes:___________________________________________  
_________________________________________________  
_________________________________________________  
_________________________________________________  
_________________________________________________  
Date __________________ Time _____________ AM/PM  
Notes:___________________________________________  
_________________________________________________  
_________________________________________________  
_________________________________________________  
_________________________________________________  
Model VSU Make-Up Air  
23  
®
Warranty  
Greenheck warrants this equipment to be free from defects in material and workmanship for a period of one year from  
the shipment date. Any units or parts which prove defective during the warranty period will be replaced at our option  
when returned to our factory, transportation prepaid. Motors are warranted by the motor manufacturer for a period of  
one year. Should motors furnished by Greenheck prove defective during this period, they should be returned to the  
nearest authorized motor service station. Greenheck will not be responsible for any removal or installation costs.  
As a result of our commitment to continuous improvement, Greenheck reserves the right to change specifications  
without notice.  
Greenheck’s Model VSU catalog provides additional  
information describing the equipment, fan performance,  
available accessories, and specification data.  
AMCA Publication 410-96, Safety Practices for Users and  
Installers of Industrial and Commercial Fans, provides  
additional safety information. This publication can be  
®
Phone: (715) 359-6171 • Fax: (715) 355-2399 • E-mail: [email protected]Web site: www.greenheck.com  
457831 • Model VSU IOM, Rev. 3, March 2009 Copyright 2009 © Greenheck Fan Corporation  
24  

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