Friedrich SM21J30A4, Руководство по обслуживанию, Страница: 53 / 70

53
Troubleshooting Heating
(Cooling/Electric Models)
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.
POSSIBLE CAUSE
PROBLEM
TO CORRECT
Fan motor does not
operate in "Constant"
or "MoneySaver"
position.
Defective motor.
Open or shorted capacitor.
Condenser fan frozen to base pan.
Loose connections.
Cooling adequate,
heating insufficient.
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. Heating capillary tube partially restricted.
Check valve leaking internally.
Reversing valve failing to shift
completely – bypassing hot gas.
POSSIBLE CAUSE PROBLEM
Fan Operates –
heating element does
not come on.
TO CORRECT POSSIBLE CAUSE PROBLEM
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.
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.
PROBLEM POSSIBLE CAUSE
TO CORRECT
Heating inadequate.
Restricted filter.
Cycling high limit control.
Exhaust or fresh air door open.
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.
Fan operates in "Con-
stant" position, but not in
"Automatic" (Money-
Saver).
PROBLEM
POSSIBLE CAUSE
TO CORRECT
Fan relay contacts open.
Inoperative system switch.
Loose connection.
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.
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.
Long "off" and "on"
cycles.
POSSIBLE CAUSE
PROBLEM
Heat anticipator (resistor) shorted.
Defective thermostat.
TO CORRECT