I need the collective minds to help solve a problem for a former student of mine. He and his fiance' just bought their first home, a condo, served by a Utica MGB100HD installed in 2005. They moved in about a month ago.
In the past two weeks the pilot has been out in the AM and does not last a cycle. I have asked Alex to take a look, to watch it between cycles, but also want to get an idea of what might be going on. He is down there to re-light it often enough, why not hang around a bit? :)
This has a standing pilot and a vent damper which is wired to stay open. (Have asked if it has "the hole" while I am at this.)
He called in a service company who replaced the thermocouple, the gas valve and now thinks it may be the aquastat which, as far as the pilot going out, makes no sense to me. Problem persists. I want to help steer him and his tech, knowing my own limitations of course. Have not seen the place yet, just got word, so what is above is all I know right now.
I should get over there this weekend to check draft, any local exhausts, dryers, etc. but also know the place is older and not well insulated, pretty drafty they say, so doubt a lack of combustion air but nor ruling anything out
Thanks in advance!
Edit: In Alex's own words:
"The pro replaced the gas valve, and noted that the vent damper was set manually
open. When he set the damper to automatic, the boiler would not fire. He was
going to replace the damper and motor, but noted that they worked fine when he
tested them outside the system. Further diagnostics lead him to believe the
issue is some sort of intermittent connection/fault in the aquastat relay.
So the pro left the damper manually open for
now, and believed that the pilot should stay lit with the new gas valve, but
that hasn’t worked out. There are two theories of what’s going on now: either
the intermittent connection in the relay is causing the system to shut itself
off randomly, or the open damper is allowing some sort of draft to put the
pilot out. His proposed next step is to replace the relay, but we’re not sure
if that will solve the problem or not."
"If you do not know the answer, say, "I do not know the answer", and you will be right!"
-Ernie White, my Dad