DU/DUH Troubleshooting
Download DU/DUH Manual
Blower Motor Fails to Run
- Is the thermostat calling for heat? Is there 115V at the burner receptacle?
- Check blower side door for seal. Repair if necessary.
- Check blower for obstructions. Replace blower if necessary.
No Gas Supply
- Check to see if manual supply valve to heater is 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.
- Supply gas pressure can be checked at 1/8" NPT pressure tap in gas supply system.
- Combination gas control gas valve or the ignition module may be faulty.
Burner Does Not Light
- 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 outlet gas pressure during ignition period.
Burner Does Not Stay Lit
- 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.
