AEC TCU Series Open Reservoir Water Temperature Control Units - Manual (Page 46)

Open Resevoir Water Temperature Control Units Page 47
Chapter 7: Troubleshooting
Condition Possible cause Solution
Unit does not turn on.
No power.
Check main disconnect, fuses,
wiring, and power lead to unit.
Wrong voltage supplied to unit.
Voltage must be within plus or
minus 10% of nameplate rating.
Defective on/off switch. Replace.
Control circuit fuse blown. Replace.
Defective control transformer. Check transformer.
Unit does not run.
Broken or loose wire in pump
motor control circuit.
Locate and repair.
Pump motor contactor holding
coil is open.
Repair or replace.
Low water level in tank.
Check water connection to fill
solenoid valve. Check reference
and low-level probes both at
tank and at the associated relay
on panel.
Pump overload light on.
Reset and test each leg for
balanced amp draws.
Low pump pressure.
Pump running in reverse.
Verify proper rotation. If not
clockwise, reverse any two
incoming power leads.
Foreign matter in the system. Clean the system.
System has minimal back
pressure, and is operating at the
far end of the pump curve. As long as there is satisfactory
process temperature control
there is no problem.
High pump pressure.
Foreign matter obstructing
system.
Clean the system.
Restricted water flow.
Check for closed valves etc. Be
sure all lines are properly sized.
System has high back pressure,
and is operating at the near end
of the pump curve; a low flow
condition.
As long as there is satisfactory
process temperature control
there is no problem.