i don't even know the name of the unit, but i successfully solved an issue w/ a burned out ignitor a few years ago w/ the help of an online forum... (the name of which escapes me)
lately the unit started failing to produce heat although the thermostat does issue the call and the unit starts up. i'm a little light on the lingo, but here goes;
the unit starts up (pump runs) and delivers a code 12 (normal) after a short while (60 seconds?) the indicator light goes constant ON (normal) after a short while (30-60 seconds?) the unit delivers a code 31. control board is 5-6 years old.
some of the things to check on the fault diagnosis list are to do w/ the vent pipe. i can feel air coming from the unit at that point during the code 31 phase so i don't think it's a blockage issue. i had a preventive maintenance service last winter & the technician's only concern was the rusted out vent pipe, which i recently replaced. (a real joy being that the unit's located in the crawl space)
any ideas on where to go from here?