This is Turtle.
When a person says what you say here. It usely is 1 of three things.
1) weak thermocouple mill-voltage from it.
2) Pilot lite jet clogged up or stopped up and not letting flames hit the
3) You have a hole in the fire chamber and it is blowing back out to blow
flames out of the pilot lite on certain times but just at certain times. The
beginning of a problem.
I will add one more.
Turtle's 1, 2 and 3 are in order of likelihood. Mine would be #4 as it
is unlikely. A strange downdraft from the vent can cause it as well,
especially if it is cold. I had this once many years ago on a water heater.
It drove me and the service man (new water heater) crazy for several weeks
until he figured it out.
this is Turtle.
i would not discount this problem at all for it does happen on some jobs. I
have seen 3 jobs in the last 5 years that this was the problem on gas
standing pilot lite going out.
probably that the pilot light is not big enough(the reason for this is
dirt gets over the pilot area and blocks the flow of gas at the pilot..
get a large refrigerator brush and with the pilot light off brush the
area right above the pilot light.... then relight it and no more
problems(unless the pilot needs adjustment???)....
If you have a good flame on the pilot, and its only covering the top 1.3rd
or so of the thermocouple like it should, then you more than likely have a
bad thermocouple that is dropping voltage to the gas valve. It is VERY
common, and a quick fix is to go to Lowes, or Home Depot and buy a new
one..or two as cheap as they are there. The reason I say two, is that
Honeywell is suppling them with a VERY cheap grade thermocouple and you
might find yourself in a month or so with another bad one. The most
expensive one they sell is about $6. The cheapest we sell is about $19
wholesale...Being that its Sunday, you wont find a Johnstone open that will
sell you a good one..and even if it was Monday, it might prove to be hard to
get one from a wholesaler anyway...maybe not..depends on your area.
Turtles post pretty much covered the bases.....worst case senario is a
cracked heat exchanger that is allowing the blower to get air into the
exchanger and blows the pilot out after the call for heat is over. It also
could be a bad gas valve that the pick and hold solienoid is going bad, and
then, the only fix would be a new TC and gas valve.
So I would have to remove the burner so that I can replace the thermocouple?
Is there a way to find out if the thermocouple is bad before I buy it? I
have a "Inter-City" furnace, model 100 GAB (manufactured in Winnipeg,
Manitoba) - any good websites on how to remove the thermocouple and burner
from this type of furnace?
Was it windy out when you pilot light went out?
I had a water heater some years back on which the pilot light would often
extinguish during a wind storm. This usually happened at nite with the
result of no hot water for a shower in the morning. I asked several people
in the plumbing and heating business about it, they all had ideas of what it
might be, but none of them seemed plausible to me.
Some years later, the hot water heater met it's end and I installed a new
one. Never had it happen again and it must be five years now.
For what it's worth, Des.
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