Condition
- Boiler safety limit wired to J6-1, J6-2 or J6-3 are open
- Condensate trap float switch open
- Thermal link switch open
- Burner doos thermostat with manual reset open
- Air pressure switch contact open
- Auto reset high limit contact open
- External High Limits open
Possible Cause
- Loose wiring to limit device
- Auto reset limit exceeded. Switch rated at 200f
- Defective auto reset high limit switch (Open when water temp is below 200f)
- Plugged condensate trap
- Thermal link blown due to temperature above 604f – ALP 285 and higher on hear of heat exchanger
- Burner door manual reset thermostat open due to temperature rise above 500f
- Air pressure switch contacts open
- Low Water Cut-Off yellow light on
See possible causes for Hard Lockout 4.
Note: For picture of low voltage circuit board – press page down. To return here press page up botton.
