stuck in purge cycle

Bob_27

I'm looking for some help. I have had this boiler to heat my home with gas since 1996. Starting this past fall, the boiler has intermittently gotten stuck in the purge cycle, which results in no heat until the emergency switch is turned off and then on again. Initially, there seemed to be a pattern of this happening between 12a.m. and 7a.m. My heating contractor replaced several problematic parts, including the hot surface ignitor, electronic control board, and the boiler sensor. Back in September, the 3" steel vent pipe was replaced due to corrosion. Due to the time pattern and a log of weather conditions, the thinking was an electrical issue. All wiring inside and outside the house checked out ok. The boiler has run ok since Dec. 26th until today(Jan.8), when it cycled off three times, all during daylight hours. Has anyone had any experience with this? Thanks!

Josh M.

I would check to see if your air presure switch is proving. Disconnect wires to the switch and check for continuity when the boiler starts.