The control coil of AC Contactor no 24 
V AC power 
Check if the relay P2 of 3-minute timer board 
have current output ,if not ,check if    P1ǃ P3 
have 24 V AC input ˈ if have 24V AC ˈ
please check if it    keep for 3 minutesˈ if so 
and P2 no output ˈchange the 3-minute 
timer board˗  if keep time < 3 minutes  ˈP2
no output ; if  P1 ǃP3 no24V ACˈ first 
check the thermostat C  ǃY terminal    have 
24 V ACˈif no 24 V ACˈthen check the 
thermostat or reset the setting temp.; if have 
24 V AC ,check if the C Y and P1ǃ P3 
connection wire cut off or fasten looselyˈif 
cut off  ˈthen change the parts. 
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 
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 
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 qF 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 
Compressor  runs,  Run  capacitor defective 
furnace trap
Condenser  fan and 
The outdoor power supply main circuit 
AC Contact not connected to the  
operation of condensate pump.
switch in “OFF” position or fuse 
blown on main circuit   
Reset the power supply switch to " ON" 
position or change the fuse and confirm the 
 Contactor 
main power lead to the
Re-connect the power supply wire, and 
has voltage present.     
compressor don’t run    power  supply wire  or not tightly  fasten   tightly  fasten. 
31
  C
entral Air Conditioner
Model: Cooling Only, 13SEER units