AEC Econo-Cool Chillers - Manual (Page 60)

AEC Water Temperature Control Units Page 59
7 Troubleshooting
Condition Possible cause Solution
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.
Unit does not turn on.
Defective control transformer. Check transformer.
Broken or loose wire in pump
motor control circuit.
Locate and repair.
Pump motor contactor holding
coil is open.
Repair or replace.
Low water pressure light on.
Check for at least 16 psig
(110.32 kPa/1.1 bars) water
pressure on WATER IN or CITY
WATER MAKEUP.
Water supply to unit is turned
off.
Open water supply.
Unit does not run.
Pump overload light on.
Reset and test each leg for
balanced amp draws.
Pump running in reverse.
Verify proper rotation. If not
clockwise, reverse any two
incoming power leads.
Foreign matter in the system. Clean the system. Low pump pressure.
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.
Foreign matter obstructing
system.
Clean the system.
Restricted water flow.
Check for closed valves etc. Be
sure all lines are properly sized.
High pump pressure.
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.
Insufficient cooling or makeup
water pressure.
Check for 25 psig (172.38
kPa/1.72 bars) water pressure
on WATER IN or CITY WATER
MAKEUP.
Pressure switch circuit is open.
Switch is broken.
Jump power across switch and
see if unit starts. Replace switch
if needed.