Ryan wrote:

Time to get the heat back on in this neck of the woods. My workshop has
floor heat, with a boiler (natural gas). This boiler (placards indicate
"MG-125-N-E Mini Gas 'super hot' with Honeywell electronics) does not have
a pilot light, but it fires up a piezo sort of lighter which ignites the
boiler and it heats the circulating water until it reaches the required
temperature, then shuts off. Cycling this scenario over and over. It
normally runs for about 3 minutes, and is off for about 10 or so. I noticed
at the end of the heating season in the spring that the boiler would not
always stay running, and have to restart several times just to get thru one
'cycle'. The unit is 3 years old, and I just do not trust the shop that
installed it to call them up about this problem. They tried to double the
quote when the job was first completed, and I have soured of that
relationship.

You can see (and hear) the piezo fire then the boiler lites and runs for
maybe 10 - 15 seconds. It shuts off, then retrys to lite. Basically it
will not stay running for as long as it needs to, and it seems like
something is shutting it off. As with so many other things these days, the
unit has an electronic control panel, with LED's and such, but no error
codes are apparent. I guess it must be time to call a different repair
person, but I thought I would try the group first, and see if anyone has any
ideas. There is a couple of wires going up to something that looks like a
temperature sending unit in the chimney, so maybe there is a problem with
that unit not sending the proper signal back to the starter, so it will not
stay running... any helpful thoughts?


two possibilities. One is that the flame sensor is bad, and is not
telling the safety
control that the flame has lit. The other possibility is that the over
temperature
sensor on the boiler has gone bad, and is telling the control to turn
off the flame.
Ahh, the draft sensor! I haven't worked with those, but that really
sounds like
it might require a 15 second timeout before the draft starts pulling.
Maybe it
requires more time, or the sensor mechanism is dirty. Since it has a
Honeywell
control, you should be able to get in touch with somebody at Honeywell to
tell you how to diagnose the problem.

Jon