Friedrich Hazardgard SH15L30-C, Service Manual

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Problem Possible Cause Action
Compressor
attempts to
start, or runs for
short periods
only. Cycles on
overload.
Compressor attempts to start
before system pressures are
equalized.
Allow a minimum of 3 minutes to allow pressures
to equalize before attempting to start.
Low or fluctuating voltage.
Check voltage with unit operating. Check for
other appliances on the circuit. Unit should be on
separate circuit for proper voltage, and be fused
separately
Incorrect wiring Connect per appropriate wiring diagram
Shorted or incorrect capacitor Replace capacitor
Restricted or low air flow through
condenser coil
Check motor fan blade.
Compressor running abnormally
hot
Check for refrigerant restriction, blocked airflow,
loose wires at compressor terminals and fan
motor capacitor voltage.
Overload opens too soon.
Change compressor if all other corrections above
are normal.
Problem Possible Cause Action
Compressor does
not start - fan
motor runs.
Thermostat contacts not closing.
Check continuity of thermostat at coldest setting. If
compressor runs, replace thermostat.
Low voltage supply.
Check for nameplate voltage. Provide proper
voltage.
Switch (On-Off) inoperative. Test for continuity.
Defective capacitor. Test with analyzer, replace if needed.
Compressor internal overload
open.
Check voltage at compressor terminals. If voltage
is satisfactory, replace compressor.
Relay open. Replace relay.
Open or shorted compressor
windings.
Check windings for continuity and resistance. If
open, replace compressor.
Problem Possible Cause Action
Does not cool, or
cools only slightly.
Thermostat open or inoperative.
Set to coldest position. Test thermostat and
replace if necessary.
Dirty air filter. Clean as recommended in Owner’s Manual.
Dirty or plugged condenser or
evaporator coil.
Clean coils.
Poor air circulation in area being
cooled.
Adjust air louvers. Check application. Check for
dirty filter or evap coil. Check fan motor. Correct as
needed.
Low capacity - undercharge. Check for leak and make necessary repairs.
Compressor not pumping properly. Replace compressor.
TROUBleSHOOTING
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