Ruud ANL-AZ 13 SEER Series, Installation Instructions Manual

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DIAGNOSTICS

General Troubleshooting Chart

WARNING:

 Disconnect all power to 

unit before servicing� Contactor may break only one 

side� Failure to shut off power can cause electrical 

shock resulting in personal injury or death�

SYMPTOM

POSSIBLE CAUSE

REMEDY

Unit will not run

•  Power off or loose electrical connection

•  Thermostat out of calibration – set too high

•  Defective control board

•  Blown fuses/tripped breaker

•  Transformer defective

•  High-pressure control open 

•  Miswiring of communications (communication 

light on continuously)

•  Check for correct voltage at line voltage connections in 

condensing unit�

•  Reset.

•  Check control board diagnostic codes.

•  Replace fuses/reset breaker.

•  Check wiring. Replace transformer.

•  Reset. Also see high head pressure remedy. The high-

pressure control opens at 610 PSIG�

•  Check communication wiring.

Outdoor fan runs, 

compressor doesn't

•  Run or start capacitor defective

•  Start relay defective

•  Loose connection

•  Compressor stuck, grounded or open motor 

winding, open internal overload�

•  Low-voltage condition

•  Replace.

•  Replace.

•  Check for correct voltage at compressor. Check and 

tighten all connections�

•  Wait at least 3 hours for overload to reset. If still open, 

replace the compressor�

•  Add start kit components.

Insufficient cooling

•  Improperly sized unit

•  Improper indoor airflow

•  Incorrect refrigerant charge

•  Air, noncondensibles, or moisture in system

•  Recalculate load.

•  Check. Should be approximately 400 CFM per ton.

•  Charge per procedure attached to unit service panel.

•  Recover refrigerant. Evacuate and recharge. Add filter 

drier�

Compressor short 
cycles

•  Incorrect voltage

•  Defective overload protector

•  Refrigerant undercharge

•  At compressor terminals, voltage must be ± 10% of 

nameplate marking when unit is operating�

•  Replace. Check for correct voltage.

•  Add refrigerant.

Registers sweat

•  Low indoor airflow

•  Increase speed of blower or reduce restriction. 

Replace air filter.

High head, low vapor 

pressures

•  Restriction in liquid line, expansion device, or 

filter drier

•  Bad TXV

•  Remove or replace defective component.

•  Replace TXV.

High head, high  

or normal vapor  

pressure – Cooling 

mode

•  Dirty outdoor coil

•  Refrigerant overcharge

•  Outdoor fan not running

•  Air or noncondensibles in system

•  Clean coil.

•  Correct system charge.

•  Repair or replace.

•  Recover refrigerant. Evacuate and recharge.

Low head, high vapor 

pressures

•  Bad TXV

•  Bad compressor

•  Replace TXV.

•  Replace compressor.

Low vapor, cool 

compressor, iced 

indoor coil

•  Low indoor airflow

•  Operating below 65°F outdoors

•  Moisture in system

•  Increase speed of blower or reduce restriction.  

Replace air filter.

•  Add Low Ambient Kit.

•  Recover refrigerant. Evacuate and recharge. Add filter 

drier�

High vapor pressure

•  Excessive load

•  Defective compressor

•  Recheck load calculation.

•  Replace.

Fluctuating head and 

vapor pressures

•  TXV hunting

•  Air or noncondensibles in system

•  Check TXV bulb clamp. Check air distribution on coil. 

Replace TXV�

•  Recover refrigerant. Evacuate and recharge.

Gurgle or pulsing 

noise at expansion 

device or liquid line

•  Air or noncondensibles in system

•  Recover refrigerant. Evacuate and recharge.

Diagnostics