AEC TCU Series Open Reservoir Water Temperature Control Units - Manual (Page 48)

Open Resevoir Water Temperature Control Units Page 49
Condition Possible cause Solution
Unit does not heat/cannot
achieve set point.
Defective heater contactor.
Visually inspect coil and
contacts; repair/replace
defective contactors.
Defective immersion heater.
Check resistance on all three (3)
legs of the heater with an ohm
meter. If not all equal, contact
factory for replacement heater.
Controller heat output open.
Check the heater output with an
ohm meter to ground. It should
read in the mega-ohm range.
Infinite or zero readings indicate
a defective output.
Heater contactor is not
energizing, but HEAT LED is on.
Set process temperature to
maximum and check for control
voltage at heater contactor.
Immersion heater elements
dirty. Remove heater and clean
elements.
Immersion heater element is
burned out.
Check heater tank for
scorched/discolored paint.
Check resistance on all three (3)
legs of the heater with an ohm
meter. Replace heater as
required.
Check for balanced amp draws,
and supply voltage. If not
present replace immersion
heater.
OUT1 indicator is on, but no
voltage on heater contact. Replace relay board on
controller.
Cooling valve is leaking. Dismantle valve and clean out.
Solenoid valve is not operating,
but COOL LED is on.
Set process temperature to
minimum and check for
magnetism on top of solenoid
coil.
Magnetism on coil. Clean coil.
Faulty/dirty solenoid valve.
Press VENT button several
times to flush the valve.