Chromalox PQ410-4 - Manual (Page 6)

2150 N. RULON WHITE BLVD., OGDEN, UT 84404
Phone: 1-800-368-2493 www.chromalox.com
14. STANDARD HEAT TRANSFER SYSTEM TROUBLE SHOOTING CHART
Problem Cause Corrective Action
System temperature too high for oil See fluid manufacturer’s data for
causing vapor lock maximum oil temperature
Vapors lock due to steam or air in oil Bleed air & steam from system, change
Insufficient suction pressure (0 or oil if problem continues
J
vacuum), pump noisy, gauges
Net positive suction pressure too low Raise expansion tank to increase suction
vibrating, discharge pressure low
head, static head should be 4-5 psig.
(below 20 psig)
(See expansion tank location No. 6)
Strainer plugged Remove and clean strainer
Valve closed Check all valves
High discharge pressure over 40 psig,
System piping blocked or restricted Check all valves, check strainer
pressure gauges fluctuating rapidly, Check process piping sizing, check for
K pump noisy, expansion tank normal, closed valves or improperly installed
system operating on bypass relief
Process piping blocked or restricted
automatic valves, check all bleed
valve valves for air or steam
Steam or water in oil Bleed system, change oil
Expansion tank too low Expansion tank should be mounted 15 ft.
L
Expansion tank overflows or “burps” above system
(over 220°F)
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
M Control relay #1 will not close
and reset
Pressure switch not closed See N
Switch set wrong Set pressure switch to approximately 5 psi
over suction gauge pressure
Check pump & motor rotation, see arrow
N Pressure switch will not close Pump running backwards on motor, reverse phase lead on circuit
breaker
Not enough or no fluid in system Check fluid levels in expansion tank,
make sure all valves are open
Pump cavitating See O
Bleed system periodically until all air or
stem is removed
Air or steam in system
Insufficient bleed valves in process
O Pump noisy and/or cavitation piping to remove trapped air
Contaminated oil 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
http://www.chromalox.com/customer-service/policies/termsofsale.aspx.