Friedrich 2000 TwinTemp YS09J10-1 Service Manual page 28

PROBLEM
Unit does not run.
PROBLEM
Evaporator coil
freezes up.
PROBLEM
Compressor runs
continually.
Does not cycle off.
PROBLEM
Thermostat does not
turn unit off.
Page 28
POSSIBLE CAUSE
Fuse blown or circuit tripped.
Power cord not plugged in.
System switch in "Off" position.
Inoperative system switch.
Loose or disconnected wiring at
switch or other components.
POSSIBLE CAUSE
Dirty filter.
Restricted air flow.
Inoperative thermostat.
Short of refrigerant.
Inoperative fan motor.
Partially restricted capillary.
POSSIBLE CAUSE
Excessive heat load.
Restriction in line.
Refrigerant leak.
Thermostat contacts stuck
Thermostat incorrectly wired.
POSSIBLE CAUSE
Thermostat contacts stuck.
Thermostat set at coldest point.
Incorrect wiring.
Unit undersized for area to be cooled.
TO CORRECT
Replace fuse, reset breaker. If repeats,
check fuse or breaker size. Check for
shorts in unit wiring and components.
Set switch correctly.
Test for continuity in each switch position.
Check wiring and connections. Reconnect
per wiring diagram.
TO CORRECT
Clean as recommended in Owner's Manual.
Check for dirty or obstructed coil - clean as re-
quired.
Test for shorted thermostat or stuck contacts.
De-ice coil and check for leak.
Test fan motor and replace if inoperative.
De-ice coil. Check temperature differential across
coil. Touch test coil return bends for same tem-
perature. Test for low running current.
TO CORRECT:
Unit undersized. Test cooling performance of unit.
Replace with larger unit.
Check for partially iced coil. Check temperature
split across coil.
Check for oil at silver soldered connections. Check
for partially iced coil. Check split across coil.
Check for low running amperage.
Check operation of thermostat. Replace if contacts
remain closed.
Refer to appropriate wiring diagram.
TO CORRECT:
Replace thermostat.
Turn to higher temperature setting to see if the unit
cycles off.
Refer to appropriate wiring diagram.
Refer to Sizing Chart.