Friedrich racservmn Service Manual page 43

Troubleshooting: Heating
PROBLEM
Fan Operates –
heating element does
not come on.
PROBLEM
Heating inadequate.
PROBLEM
Fan operates in "Con-
stant" position, but not in
"Automatic" (Money-
Saver).
PROBLEM
Long "off" and "on"
cycles.
PROBLEM
Fan motor does not
operate in "Constant"
or "MoneySaver"
position.
PROBLEM
Cooling adequate,
heating insufficient.
(Cooling/Electric Models)
POSSIBLE CAUSE
Heater relay or contactor coil open.
Heater relay or contactor stuck open,
pitted or burned.
High limit control open.
Open thermal fuse.
Open or shorted element.
Loose connections.
POSSIBLE CAUSE
Restricted filter.
Cycling high limit control.
Exhaust or fresh air door open.
POSSIBLE CAUSE
Fan relay contacts open.
Inoperative system switch.
Loose connection.
POSSIBLE CAUSE
Heat anticipator (resistor) shorted.
Defective thermostat.
POSSIBLE CAUSE
Defective motor.
Open or shorted capacitor.
Condenser fan frozen to base pan.
Loose connections.
POSSIBLE CAUSE
Heating capillary tube partially restricted.
Check valve leaking internally.
Reversing valve failing to shift
completely – bypassing hot gas.
TO CORRECT
Check continuity of coil.
Inspect, test continuity with ohmmeter.
Check continuity – if open, replace.
Check continuity. Check reason for failure.
Check voltage across heater terminals. Check
amperage draw of heater.
Tighten all terminals.
TO CORRECT
Clean as recommended in Owner's Manual.
Control is set to open at 155°F ± 5°F and close at
130°F ± 8°F. If cycling prematurely, replace control.
Check position of fresh air door control slide. Adjust
cable if door does not close properly.
TO CORRECT
Check continuity of fan relay. NOTE: Some models
have the fan relay energized during the heating
cycle while others do not.
Check continuity between terminals "L2" and "3" of
the system switch.
Check connections on system switch and fan relay.
TO CORRECT
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.
Replace thermostat and check operation.
TO CORRECT
Check and replace.
Replace capacitor and check.
Check if drain pan valve is open. If not, replace.
Check all connections. Check voltage to fan motor.
TO CORRECT
Check for partially starved outer coil. Replace
heating capillary tube.
Switch unit several times from heating to cooling.
Check temperature rise across coil. Refer to specifi-
cation sheet for correct temperature rise.
Deenergize solenoid coil, raise head pressure,
energize solenoid to break loose. If valve fails to
make complete shift, replace valve.
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