No flame detected.
- Check that ground lead is properly connected, replace if defective.
- Check that gas cock is open.
- Check inlet gas pressure; correct if needed.
- Check power supply.
- Check electrodes for visual damage; replace if defective.
- Check flue gas system; clean or repair if defective.
- Check gas/air ratio; correct if out of range.
- Check gas valve; replace if defective.
- In room air operation, check air supply or ventilation apertures.
- Clean the condensate trap.
- Remove diaphragm at fan inlet connection and check for contamination or cracks.
- Check heat exchanger for soiling.
- Check gas cock; replace if defective.
- Insert code plug correctly; replace if defective.
