Chromalox Heat Pump PQ410 4 User Manual

SERVICE MANUAL  
4
CES  
(Supersedes PQ410-3)  
PQ410-4  
161-048978-001  
JULY, 2009  
Electric Fluid Heat Transfer Systems  
GENERAL  
This Service Manual is furnished as an aid to help start-up and  
service Chromalox Heat Transfer Systems. Listed below are con-  
ditions which could occur during start-up and operation.  
CAUTION: Hazard of Electric Shock. Any installa-  
tion involving electricity must be grounded to earth  
to eliminate shock hazard.  
1.  
USE THE RIGHT HEAT TRANSFER FLUID  
DO read manufacturer’s technical bulletins and instructions care-  
fully. Some heat transfer fluids may ignite or burn spontaneously  
if not properly used.  
Chromalox Fluid Heat Transfer Systems are designed for a par-  
ticular heat transfer fluid or a class of heat transfer fluids. If you  
are not sure you are using an accepted heat transfer fluid, check  
with your local Chromalox sales and application engineering  
office listed on back cover or consult Chromalox Bulletin PQ301  
for the correct heat transfer fluid.  
turer. If you plan to switch fluids, check with the fluid manufac-  
turer to determine the following.  
A. Is the new fluid compatible with the old?  
B. What is the recommended cleaning method to remove the old  
fluid, its sludge, or any deposits remaining in the system?  
C. Does the fluid manufacturer have a reclaiming service for used  
fluid? Do they have a recommended procedure for disposal of  
used or old fluid?  
CAUTION: To avoid possible damage to the heaters  
do not energize the heater unless the system is  
filled with fluid.  
DO NOT mix heat transfer fluids unless authorized and approved  
by the fluid manufacturer.  
All heat transfer fluids are not compatible with each other,  
whether made by the same manufacturer or a different manufac-  
2.  
PIPE STRAIN  
DO provide for expansion and contraction of process piping and  
connections to the system. Piping strains can cause pump and  
motor mis-alignment, excessive wear on pump body, bearings and  
stuffing box packing or mechanical seal and will eventually cause  
failure of the pump and system.  
Piping should be properly supported so pump can be removed  
without changing the position of the piping. If piping moves when  
the pump is removed, pump malfunction is probably due to stress-  
es and twisting caused by the piping. These stresses will multiply  
when the system is hot due to thermal expansion.  
3.  
PIPING RESTRICTIONS  
DO provide sufficient cross sectional area in the process piping  
connections equivalent to the system pipes. In order to prevent  
undue pressure drop, maximum velocity in all piping should be  
less than 10 feet per second.  
DO NOT use process piping connections smaller than the pipes  
used in the system.  
If there is a high differential pressure between the inlet and out-  
let of the heat transfer system at operating temperature, this is  
probably due to a piping restriction. A continuing high differential  
pressure can cause excessive wear on the pump and pump stuffing  
box packing or mechanical seal and will eventually cause prema-  
ture failure of the pump. The major causes of restrictions are:  
A. Inlet and outlet pipes smaller than provided on the system.  
B. Piping many processes in series with one another. To reduce  
the pressure drop of the system, equipment should be re-piped  
in balanced parallel flow.  
© 2010 Chromalox, Inc.  
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6.  
EXPANSION TANK LOCATION  
Note: If the expansion tank cannot be mounted above the highest  
point in the system, or if the system is going to operate above the  
boiling temperature of the heat transfer fluid, the expansion tank  
will have to be pressurized with air or nitrogen. This eliminates the  
possibility of heat transfer fluid flashing into vapor in the heater,  
at the point of high velocity in the system or at the suction of the  
pump which will cause the pump to vapor lock due to insufficient  
NPSH (net positive suction head). On hot oil heat transfer systems,  
this pressurizing is usually done with nitrogen as this eliminates  
the possibility of the hot fluid coming in contact with oxygen thus  
reducing the possibility of oxidation, extending the life of the heat  
transfer fluid. This pressure should be 5-10 PSI above the vapor  
pressure of the heat transfer fluid at its operating temperature.  
DO NOT pressurize expansion tank or system unless proper safe-  
ty relief valves are provided.  
WARNING: If expansion tank is to be pressurized,  
then it must be equipped with safety relief valve(s).  
If this pressure exceeds 15 PSIG, then the heat  
transfer system and expansion tank should be  
ASME coded.  
DO NOT mount expansion tank directly on top of system unless  
absolutely necessary. If mounted on system, provisions must be  
made for cooling of the expansion tank line. Maximum safe oper-  
ating temperatures are reduced when expansion tank is mounted  
on system unless positive suction pressure of 2 to 3 psig is main-  
tained on pump.  
7.  
SYSTEMS MOUNTED ABOVE PROCESS EQUIPMENT  
(Ceiling or Platform mounted)  
When mounting system above process equipment, check to be  
B. The expansion tank should be connected into the pump suction  
line and be located high enough to create the necessary NPSH  
(See No. 6). If the expansion tank cannot be elevated then it  
should be pressurized with air or nitrogen to obtain the neces-  
sary NPSH. This will create a positive head on the pump and  
prevent the heat transfer fluid from flashing into vapor at the  
pump suction when the system is operating at temperatures  
equal to or exceeding the vapor temperature of the heat trans-  
fer fluid.  
sure the pump will not be vapor locked. The cause for vapor lock  
is insufficient NPSH (net positive suction head). This problem is  
particularly prevalent on systems with centrifugal pumps, but also  
can appear on systems with positive displacement pumps. The  
things to check when a system is mounted above the process  
equipment are as follows:  
A. Piping: Eliminate all unnecessary turns and restrictions in the  
return piping which could cause a vapor lock.  
8.  
PUMP ALIGNMENT  
DO NOT allow pump to hammer or cavitate. Excessive vibration  
B. Check the ends of the meshed teeth on the coupling jaws with  
a feeler gage. The ends of the teeth should be equidistant  
around the circumference of the coupling. Do not rotate shaft  
when making this check. Allowance must be provided for  
pump shaft and motor shaft expansion.  
will damage pump and may break pump castings.  
CAUTION: All pump and motor mounts and motor-belt should be  
checked and tightened if necessary. These sometimes loosen dur-  
ing transit.  
Belt Driven — The belt has been properly aligned and adjusted  
for the proper deflection prior to shipment from the Chromalox  
factory. The proper deflection is 1/4”.  
Direct Coupled — The pump and motor on each Chromalox heat  
transfer system is factory aligned prior to shipment. However, as  
recommended in our instruction sheet on each particular heat  
transfer system, the pump and motor could become misaligned in  
transit and therefore, should be realigned in the field after the unit  
has been permanently set in place. Misalignment can cause wear  
on the pump shaft, packing or mechanical seal and bearings. It will  
cause excessive stuffing box leakage and will eventually cause  
complete failure of the pump and in turn, the system.  
To check alignment:  
A. Place a straight edge across the coupling, it should be in full  
contact with both rims at the top, bottom and both sides. Rotate  
coupling by hand and repeat this check.  
Figure 1  
9.  
PUMP PACKING ADJUSTMENT  
Pumps with packed stuffing box or seals may require adjust-  
When system reaches temperature, tighten the two packing gland  
1
ment during system start up. Packed seals are designed to leak  
some oil for proper lubrication of the pump shaft. Drip pans and  
drain connections are provided on these pumps to contain the oil  
and allow convenient removal.  
nuts evenly, approximately /  
4
turn at a time until the shaft seal  
leaks 1 to 2 drops per minute. Do not overtighten or shaft damage  
will occur.  
Note: If normal oil leakage from a packed pump is unacceptable  
in the application, mechanical seal pumps are available at extra  
cost. Contact factory.  
Packed pumps will frequently leak oil at start up until the sys-  
tem reaches operating temperature and the seals seat on the shaft.  
-3-  
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10.  
OPERATING ABOVE THE MAXIMUM ALLOWABLE TEMPERATURE OF  
THE HEAT TRANSFER SYSTEM OR HEAT TRANSFER FLUID  
DO NOT attempt to operate any heat transfer system or heat trans-  
fer oil at temperatures higher than those recommended by the man-  
ufacturer.  
Chromalox heat transfer systems are designed for a particular  
maximum temperature. If you do not know this design tempera-  
ture, check with the Chromalox factory or consult the individual  
instruction sheet for that system. Exceeding the designed tem-  
perature of the heat transfer system will void our warranty.  
Exceeding the temperature limits of the heat transfer fluid will  
cause its thermal breakdown or degradation. This will result in the  
formation of sludge in the system and carbon on the heating elements  
and eventually cause pump and heater failure. If you do not know this  
maximum temperature, check with the fluid manufacturer.  
WARNING: In hazardous or explosive areas, the  
pipe surfaces of oil type heat transfer systems  
could achieve temperatures higher than allowed  
for Class I, Group D, Division I.  
11.  
INSUFFICIENT HEAT  
The following are the major causes of insufficient heat:  
A. Low voltage.  
B. Blown fuse in heater circuit.  
D. Restriction in flow of heat transfer fluid to process. (See No. 3  
Piping Restrictions)  
E. Thermostat set too low.  
F. Piping or process not insulated. This is a common fault. The  
piping in heat transfer systems is shipped from the factory  
uninsulated, only the heating chamber is insulated. The piping  
in the heat transfer system should be insulated at the same time  
the piping from the system to the process is insulated.  
CAUTION: Hazard of Electrical Shock. Make sure  
all electrical power is disconnected before servic-  
ing or replacing any electrical component.  
C. System too small for application (not enough kW).  
1. Increased work load.  
2. Changed product or process.  
12.  
MISCELLANEOUS PROBLEMS  
A. Leaking pipe joints can be caused by poor threads, using the  
wrong or old gaskets and unsupported piping. New gaskets  
should be used whenever a flanged pipe joint is made. A good  
rule of thumb for systems operating above 350°F is to use  
flanged or welded connections on all pipe larger than 3/4”. On  
high temperature systems, threaded pipe will loosen with heat-  
ing and cooling of system and in time will leak.  
3. Misalignment of pump will cause high leakage of oil pack-  
ing type stuffing box and complete failure of mechanical  
seal type.  
4. Unusually high back pressure at high temperature.  
C. Pump bearing failure.  
1. Misalignment.  
2. Cavitation (for causes of pump cavitation, see sections 3, 4  
and 9).  
B. Excessive leakage at stuffing box of pump.  
1. Packed type — normal leakage rate is approximately five  
(5) drops per minute when cold, 1 — 2 when at operating  
temperature.  
3. Excessively high pressure at operating temperature. Can be  
caused by incorrect or poor quality heat transfer fluid.  
Water in a heat transfer fluid can also cause high pressure.  
D. Spillage from expansion tank.  
1. Tank too small to accept expansion of liquid in system.  
2. Expanding pocket of air or steam in system forcing heat  
transfer fluid to back-up into expansion tank.  
E. Sludging of heat transfer fluid is caused by either too high a  
heating element temperature or improper materials used in cus-  
tomer’s piping or process.  
Note: Improper tightening of stuffing box gland will  
always cause abnormal leakage and possible shaft damage  
(see Instruction Sheet for unit).  
2. Mechanical seal type — water cooling of mechanical seals  
is recommended when operating over 350°F. Most types  
should not leak either water or oil. However, some water  
cooled high temperature seals are designed to leak steam or  
water at a constant rate.  
DO NOT use brass valves or fittings. Generally speaking on  
oil type systems, no copper or copper bearing alloys should be in  
contact with the heat transfer fluid.  
DO NOT connect cooling water to flush ports of mechanical seal  
pumps. Water will be forced thru the seals and contaminate the oil.  
(Check manufacturer for proper connections.)  
13.  
START UP SUPERVISION  
Factory trained personnel are available upon request for those  
customers who are unfamiliar with the initial start-up.  
Contact your local Chromalox sales and application engineer list-  
ed on back cover and request Bulletin PQ901.  
-4-  
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14.  
STANDARD HEAT TRANSFER SYSTEM TROUBLE SHOOTING CHART  
Problem  
Cause  
Main power feed off  
Corrective Action  
Turn on main power  
Circuit breaker off  
Turn on circuit breaker  
A
Power light off  
Control transformer  
Primary fuse blown  
Secondary fuse blown  
Transformer bad  
Replace fuse  
Replace fuse  
Check and/or replace  
Pilot light blown  
Float switch open  
Replace bulb  
Add oil to system  
If no float switch, jumper terminals 4 & 5  
B
C
Power light on, pump will not start  
Motor overloads tripped  
Motor starter bad  
Motor fuse blown  
Motor burned out  
Broken belt  
Reset overloads, check running current  
Check motor starter coil  
Replace fuse, check motor overloads  
Replace motor, check motor for overload  
Check and replace belt  
Power light on, pump light on, motor  
not running  
Broken coupling  
Check and replace coupling  
Power light on, pump light on, motor  
running, pump not running  
D
E
Turn off system and rotate pump by hand  
if jammed, disassemble and clean pump.  
Check and clean strainer.  
Pump jammed by slag or foreign object  
Control relay #1 not closed  
See M  
Power light on, pump light on,  
motor running, pump running heat  
will not come on  
Heat on-off switch in off position  
Process control ITC-1 set too low  
Turn switch to on  
Set process control to desired temperature  
See items, pump noisy, see O;  
insufficient suction pressure, see J:  
high discharge pressure, see K  
No oil flow  
F
Insufficient heat  
Process piping too small or restricted  
Check process piping, check heat transfer  
area of platen, etc.  
Heater fuses blown  
Check and replace fuses  
Heater elements burned out  
Check continuity and resistance of  
elements  
Excessive operating pressure over  
40 psig  
See K  
Packing gland loose  
Check and adjust packing gland nuts per  
manufacturer’s recommendations  
G
Pump packing gland leaking  
Use mechanical seals or sealless pumps  
where no oil leaks can be tolerated  
Wrong pump specified  
Mechanical seals on pumps should be  
water cooled over 350°F.  
Failure to do so will cause seal failure  
and leaks.  
Improper cooling of seals  
Check piping and flange alignment  
retighten and torque all bolts to  
specifications  
H
I
System leaks when filling  
Rough handling during shipment  
Expansion and contraction due to  
temperature has loosened connections  
Check all flange bolts and connections  
retighten and torque to manufacturer’s  
specifications  
System leaks at temperature and after  
cool down  
Wrong gasket materials  
Replace gaskets as necessary, use spiral  
wound or Grafoil® gaskets  
-5-  
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14.  
STANDARD HEAT TRANSFER SYSTEM TROUBLE SHOOTING CHART  
Problem  
Cause  
Corrective Action  
System temperature too high for oil  
causing vapor lock  
See fluid manufacturer’s data for  
maximum oil temperature  
Vapors lock due to steam or air in oil  
Bleed air & steam from system, change  
oil if problem continues  
Insufficient suction pressure (0 or  
vacuum), pump noisy, gauges  
vibrating, discharge pressure low  
(below 20 psig)  
J
Net positive suction pressure too low  
Raise expansion tank to increase suction  
head, static head should be 4-5 psig.  
(See expansion tank location No. 6)  
Strainer plugged  
Remove and clean strainer  
Check all valves  
Valve closed  
System piping blocked or restricted  
Check all valves, check strainer  
High discharge pressure over 40 psig,  
pressure gauges fluctuating rapidly,  
pump noisy, expansion tank normal,  
system operating on bypass relief  
valve  
Check process piping sizing, check for  
closed valves or improperly installed  
automatic valves, check all bleed  
valves for air or steam  
K
Process piping blocked or restricted  
Steam or water in oil  
Bleed system, change oil  
Expansion tank too low  
Expansion tank should be mounted 15 ft.  
above system  
Expansion tank overflows or “burps”  
(over 220°F)  
L
M
N
Expansion tank line too short  
Lengthen expansion tank line to cool oil  
and provide cold oil seal  
Tank too small for system  
Check volume on process piping  
Over-temperature control open  
Set thermostat above process temperature  
and reset  
Control relay #1 will not close  
Pressure switch will not close  
Pressure switch not closed  
Switch set wrong  
See N  
Set pressure switch to approximately 5 psi  
over suction gauge pressure  
Check pump & motor rotation, see arrow  
on motor, reverse phase lead on circuit  
breaker  
Pump running backwards  
Not enough or no fluid in system  
Pump cavitating  
Check fluid levels in expansion tank,  
make sure all valves are open  
See O  
Bleed system periodically until all air or  
stem is removed  
Air or steam in system  
Contaminated oil  
Insufficient bleed valves in process  
piping to remove trapped air  
O
Pump noisy and/or cavitation  
Change oil  
Pump damaged by overtightened  
packing gland  
Replace pump  
Insufficient suction pressure  
Suction pressure should be 4-5 psig  
Limited Warranty:  
Please refer to the Chromalox limited warranty applicable to this product at  
2150 N. RULON WHITE BLVD., OGDEN, UT 84404  
Phone: 1-800-368-2493  
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