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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