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PROBLEM POSSIBLE CAUSE TO CORRECT
Check operation of unit. Replace overload if Overload inoperative. Opens too
soon.
system operation is satisfactory.
Compressor
attempts to
start, or runs
for short
periods only.
Compressor attempts to start
before system pressures are
equalized.
Allow a minimum of 2 minutes for pressures
to equalize before attempting to restart.
Cycles on
overload.
Low or fluctuating voltage. Check voltage with unit operating. Check for
other appliances on circuit. Air conditioner
should be on separate circuit for proper
voltage, and be fused separately.
8.4 Troubleshooting Heating (Cooling/Electric Heater Models)
PROBLEM P OSSIBLE CAUSE TO CORRECT
Heater relay or contactor coil open. Check continuity of coil. Inspect, test
continuity with ohmmeter.
Heater relay or contactor stuck
open, pitted or burned.
Check continuity – if open, replace.
High limit control open. Check continuity. Check reason for failure.
Open thermal fuse. Check voltage across heater terminals.
Open or shorted element. Check amperage draw of heater.
Fan
Operates –
heating
element does
not come on.
Loose connections. Tighten all terminals.
Restricted filter. Clean as recommended in Owner’s Manual.
Cycling high limit control. Control is set to open at 155°F± 5°F (68.3°C
+/- 15°C) and close at 130°F± 8°F (54.4°C +/-
13°C). If cycling prematurely, replace control.
Heating
inadequate.
Exhaust or fresh air door open. Check position of fresh air door control slide.
Adjust cable if door does not close properly.
Fan relay contacts open. Check continuity of fan relay.
NOTE: Some models have fan relay energized
during heating cycle while others do not.
Inoperative system switch. Check connections on system switch and
fan relay.
Fan operates
in "Constant"
speed, but
not in "Auto"
Loose connection. Check connections on system switch and
fan relay.
Heat anticipator (resistor)
shorted.
Disconnect power to unit. Remove resistor
from thermostat bulb block. Plug in unit and
allow to operate. Feel resistor for heat. If no
heat is felt, replace resistor.
Long "off"
and "on"
cycles.
Defective temperature sensor. Replace temp. sensor and check operation.
Service Manual
Room Air Conditioner with R-410A
Heat Controller, Inc.
32