Friedrich racservmn Service Manual page 37

PROBLEM
POSSIBLE CAUSE
Dirty filter.
Restricted air flow.
Evaporator coil
freezes up.
Inoperative thermostat.
Short of refrigerant.
Inoperative fan motor.
Partially restricted capillary.
PROBLEM POSSIBLE CAUSE
Excessive heat load.
Compressor runs
Restriction in line.
continually.
Refrigerant leak.
Does not cycle off.
Thermostat contacts stuck
Thermostat incorrectly wired.
POSSIBLE CAUSE
PROBLEM
Thermostat contacts stuck.
Thermostat set at coldest point.
Thermostat does not
turn unit off.
Incorrect wiring.
Unit undersized for area to be cooled.
PROBLEM
Compressor attempts
to start, or runs for
short periods only.
Cycles on overload.
PROBLEM
Thermostat does not
turn unit on.
POSSIBLE CAUSE
Overload inoperative. Opens too soon.
Compressor attempts to start before
system pressures are equalized.
Low or fluctuating voltage.
Incorrect wiring.
Shorted or incorrect capacitor.
Restricted or low air flow through
condenser coil.
Compressor running abnormally hot.
POSSIBLE CAUSE
Loss of charge in thermostat bulb.
Loose or broken parts in thermostat.
Incorrect wiring.
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 tempera-
ture. 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.
TO CORRECT
Check operation of unit. Replace overload if
system operation is satisfactory.
Allow a minimum of two (2) minutes for pressures
to equalize before attempting to restart. Instruct
customer of waiting period.
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.
Refer to appropriate wiring diagram.
Check by substituting a known good capacitor of
correct rating.
Check for proper fan speed or blocked condenser.
Check for kinked discharge line or restricted condenser.
Check amperage.
TO CORRECT
Place jumper across thermostat terminals to check
if unit operates. If unit operates, replace thermostat.
Check as above.
Refer to appropriate wiring diagram.
37