APEX Troubleshooting

Burner Blower / Motor Fails to Run

Check heat exchanger blower power cord is connected to burner box cable connector.
Check blower for obstructions. Replace blower if necessary.

Check air pressure switch performance with a manometer – Compare with switch setting.
Ensure the correct size of exhaust and air intake pipes were used per the instruction manual for vent length.
Ensure maximum number of elbows or equivalent feet of both pipes was not exceeded.
Ensure there are no obstructions in the exhaust and air intake pipes.
If the air pressure switch performance test results prove the air pressure switch is working properly, and all other steps are followed, and fault code persist – replace the control.

Check to see if manual supply valve to heater is ON (Open). No manifold pressure indicates valve is closed. Gas pressure downstream of gas control can be measured by connecting a manometer to pressure tap on control. If the valve is closed, neither the gas valve knob on heater gas control is ON.
Supply gas pressure can be checked at 1/8" NPT pressure tap in gas supply system.

Is spark visible through site glass during ignition trial? If no, further electrical checks by a qualified service person are required.
Check to see if gas lines were properly purged of air.
Check inlet and manifold gas pressure during ignition period.
Check for proper orifice and air plate.

Check ground wire continuity.
Check insulation on the igniter leads.
Measure flame signal current; it should be between 2 to 6 micro amps DC. Minimum 0.8 micro amps
Clean flame rod if necessary.
Replace module if necessary.