AAON HA-50 - Manual (Page 8)

8
TROUBLE POSSIBLE CAUSE
ELECTRIC HEATING
SYSTEM OFF
1. Check power at line side of contactor(s).
2. Thermostat not set for heating.
1. Overload relay tripped.
2. Heater Relay not energized.
3. Blower Contactor not energized.
4. Capacitor shorted or open (PSC motors only).
1. Blower running backwards.
2. Dirty air filters.
3. Dirty coils.
4. Duct obstruction.
5. Belts loose.
1. One or more heater contactors are open.
2. Limit switches are open.
3. Heater relay open.
4. Heat strips burned out.
BLOWER DOESN'T DELIVER AIR
EVAPORATOR MOTOR WILL NOT RUN
BLOWER COMES ON, BUT LITTLE OR NO
HEAT
FAN MOTOR RUNS HOT AND CUTS OUT
1. Check power at lineside of contactor(s).
2. Thermostat not set for cooling.
3. High pressure control tripped.
4. Low pressure switch open (loss of charge).
1. Overload thermal protector open in motor.
2. Motor run capacitor open or shorted.
3. Motor failed.
4. Fan or shaft stuck.
1. Overload thermal protector open in motor.
2. Relay not closing.
3. Motor failed.
4. Capacitor shorted or open (PSC motors only).
5. Stuck shaft or blower wheel.
1. Check for low refrigeration charge.
2. Compressor overload setting.
3. Ambient temperature too low.
4. Filters dirty or air flow restricted.
5. Evaporator blower not running.
1. Line voltage too high.
1. Line voltage too low.
2. Limit switches are open.
3. Overload or pressure control tripped.
1. Blower running backwards.
2. Dirty filters.
3. Duct obstruction.
4. Belts loose.
SYSTEM OFF
BLOWER DOES NOT DELIVER AIR
COMPRESSOR WILL NOT START
COMPRESSOR SHORT CYCLES
EVAPORATOR BLOWER WILL NOT RUN
CONDENSER FAN WILL NOT RUN
COOLING PACKAGE
SERVICING, TROUBLE SHOOTING, INSPECTIONS & MAINTENANCE