"David Combs" wrote in message
...
Several years now, the thermocouple on the boiler has
crapped out on only the COLDEST day (thus far) of the year.

Again this year too -- this morning, pilot was out,
and it wouldn't relight. And temp outside was 17(F)!

(Window in boiler-room is open a few inches, due to
air-flow problem -- we have a fan in the pipe that goes
up the chimney.)

Now, in the past, replacing the thermocouple (plumber did the work)
would fix it.


-----

Question: just wondering -- any substance to this
apparent correlation between
super-cold temperature and crap-out of thermouple?

question: would placing electric heater near the boiler
possibly help?

Thanks!

David



Super cold weather will cause your furnace to run more often but that should
not accelerate the death of the thermocouple.

Preheating the combustion air which comes from inside the house or garage
(is it as cold as outside where the furnace is?) will not increase the
lifetime of the thermocouple. It will only cause you to send money up the
chimney.

If your furnace is located in an area subject to full outside cold air, that
would be atypical and the cold temp may degrade some components due to
extreme thermal expansion and metal fatigue.

Maybe its not the cold, maybe it has something to do with conditions off
season (summer) like condensation that sets the stage for premature failure
when usage is at its peak.

Keep a spare thermocouple on hand and learn how to replace it.

Is it an older model with a full time pilot light or a newer electronic
model that ignites the pilot before igniting the main burner.

Maybe you were just unlucky.