34
RT-SVX069D-EN
Method 2
To reset the system at the unit, cycle the unit power by
turning the disconnect switch “Off” and then “On”.
Table 15. Troubleshooting chart
Symptom
Possible Cause
Remedy
Unit will not run
Power off or loose electrical connection
Check for correct voltage at compressor contactor in control box
Thermostat out of calibration-set too high
Reset
Failed contactor
Check for 24 volts at contactor coil - replace if contacts are open
Blown fuses
Replace fuses
Transformer defective
Check wiring - replace transformer
Interconnecting low voltage wiring damaged Replace thermostat wiring
Condenser fan runs, compressor
doesn't
Run or start capacitor failed (single phase only) Replace
Loose connection
Check for correct voltage at compressor - check and tighten all
connection
Compressor stuck, grounded or open motor winding open
internal overload
Wait at least 2 hours for overload to reset. If still open, replace the
compressor.
Low voltage condition
Determine cause and correct. At compressor terminals, voltages
must be within 10% of rating plate volts when unit is operating.
Insufficient cooling
Improperly sized unit
Recalculate load
Improper airflow Check - should be approximately 400 CFM per ton.
Incorrect refrigerant charge Charge per procedure attached to unit service panel.
Air, non-condensible or moisture in system Recover refrigerant, evacuate & recharge, add filter drier
Incorrect voltage
Determine cause and correct. At compressor terminals, voltages
must be within 10% of rating plate volts when unit is operating.
Compressor short cycles
Incorrect voltage
At compressor terminals, voltage must be ±10% or nameplate
marking when unit is operating.
Defective overload protector Replace - check for correct voltage
Refrigerant undercharge Add refrigerant
Compressor operates continuously
Dirty air filter Replace filter
Unit undersized for load Decrease load or increase unit size
Thermostat temperature set too low
Reset thermostat
Low refrigerant charge Locate leak, repair, and recharge
Air in system Recover refrigerant, evacuate system, and recharge
Outdoor coil dirty or restricted
Clean coil or remove restriction
Registers sweat Low evaporator airflow Increase speed of blower or reduce restriction - replace air filter
High head-low vapor pressure
Restriction in liquid line, expansion device or filter drier Remove or replace defective component
Flow check piston size too small Change to correct size piston
Incorrect capillary tubes Change coil assembly
TXV does not open Replace TXV
High head-high or normal vapor
pressure - Cooling mode
Dirty condenser coil
Clean coil
Refrigerant overcharge Correct system charge
Condenser fan not running Repair or replace
Air or non-condensible in system Recover refrigerant, evacuate & recharge
Low head-high vapor pressures
Defective compressor valves Replace compressor
Incorrect capillary tubes Replace coil assembly
Troubleshooting
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