AAON RK-60 - Manual (Page 10)

10
BURNER GOES "OFF" ON HIGH LIMIT
SERVICING
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
1. Check power and gas supply.
2. Check thermostat switches and settings.
3. Check 24 volt power to ignition control.
1. Check for power at main gas valve.
2. Defective gas valve.
3. Loose or broken connection to gas valve.
4. Check limit controls for open.
5. Check continuity of differential pressure switch with motor
turning. If open, replace differential pressure switch.
6. Defective ignition control.
1. Thermostat not calling for heat.
2. Relay not closing. (No power to motor)
3. Motor stuck or winding open.
4. Internal motor overload open.
1. Unit blower not coming on. (Check fan control)
2. Blower motor running backward.
3. Filters dirty.
4. Ducts obstructed or dampers closed.
5. Manifold gas pressure too high.
1. Hand valve "off" (turn to on)(main gas valve).
2. Gas off or very low pressure.
3. Check for power at main gas valve.
4. Check continuity of differential pressure switch with motor
turning. If open, replace differential pressure switch.
5. Sparker sensor out of adjustment.
6. Main orifice blocked.
1. Defective Ignition Control.
2. See cooling trouble shooting page 19.
SYSTEM OFF
BLOWER COMES ON, BUT LITTLE OR NO
HEAT
IGNITION ON, BURNER WON'T LIGHT
GAS HEATING
COMBUSTION AIR BLOWER WON'T RUN
BURNER WON'T COME ON
SUPPLY FAN BLOWER WON'T RUN