Commercial Air Conditioner
Model: heat pump, 10SEER UNITS
42
Run or start capacitor defective
Replace
Loose connection
Check and tighten all connections.
Compressor stuck, grounded or open
motor winding, open internal overload
Wait for 2 hours for overload to reset.
Replace compressor if still open.
Low voltage condition
At compressor terminals, voltage must be
within 10% of rating plate volts when unit is
running.
Condenser fan runs,
compressor doesn’t
Low voltage condition
Add start kit components
Run capacitor defective
Replace
Loose connection
Check and tighten all connections.
Fan stuck, grounded or open motor
winding, open internal overload
Wait for 2 hours for overload to reset.
Replace Fan if still open.
Low voltage condition
At compressor terminals, voltage must be
within 10% of rating plate volts when unit is
running.
Defective overload protector
Replace – check for correct voltage
compressor runs,
Condenser fan
doesn’t
Refrigerant undercharge
Add refrigerant
Register sweat
Low evaporator airflow
Increase blower speed or reduce restriction
– replace air filter
Restriction in liquid line, metering
device or filter drier
Replace defective components
Flowrator piston size too small
Change to correct size piston
High head – Low
vapor pressures
Incorrect capillary tubes
Change coil assembly
Blocked outdoor coil
Clear away leaves and other debris
Refrigerant overcharge
Correct system charge
Condenser fan not running
Repair or replace
High head – High or
normal vapor
pressures
Air, non-condensibles or moisture in
system
Recover refrigerant, evacuate & recharge,
add filter drier
Flowcheck piston size too large
Change to correct size piston
Defective compressor valves
Replace compressor
Low head – High
vapor pressures
Incorrect capillary tubes
Replace coil assembly
Low evaporator airflow
Increase blower speed or reduce restriction
– replace air filter
Operating below 65
°
F outdoors
Add low ambient kit
Low vapor – cool
compressor – iced
evaporator coil
Moisture in the system
Recover refrigerant, evacuate & recharge,
add filter drier
Excessive load
Recheck load calculation
High vapor pressure
Defective compressor
Replace
Fluctuating head and
vapor pressures
Air or non-condensibles in system
Recover refrigerant, evacuate & recharge.
Pulsing noise at
metering device or
liquid line
Air or non-condensibles in system
Recover refrigerant, evacuate & recharge