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imtermittent pilot lite

I have a GE gas water heater that the pilot lite goes out imtermittently sometime 1 or2 times a day then not for days.
the thurmo coupling has been change 4 times and the gas valve also
has been changed. we have had local plumber in to look at the problem and have made repairs hoping to resolve the problem but still we get the same thing happening. the flow has draft,the closet that the heater is in is well ventilated,we have a 3/4" gas
line down to 1/2 for the heater.any help?

Re: imtermittent pilot lite

I'd concider a backdraft down the stack blowing out the pilot.Look for wind velocity and/or direction when this problem occurs.For example,I used to have a similar problem in a house I used to have when we had a rather strong east wind. The usual direction was from the west or the south so it was hard to track down until I noticed the connection.

Re: imtermittent pilot lite

Besides what's already been suggested (very possible).......

Is the pilot flame of sufficient size?.......and is the thermo-couple well emersed in that flame?

Also......you don't state how old this WH is. If the pilot flame seems a bit on the small/weak size....it is very possible that the pilot orifice has become choked down or "mis-directed" due to a build-up of carbon deposits. The remedy to this is to remove the entire pilot assembly and clean off those deposits. This *should/would* re-establish a full-size flame that then emerses the TC fully... as it needs to be.

Mighty tough call from here as to what the actual problem is. You might also have a bad/faulty main control valve. This should be suspected if there are no winds when the pilot goes out and the thermo-couple is well-emersed in an adequate sized flame. If so...it wouldn't be the first time that a main control valve was at fault.

Re: imtermittent pilot lite

we have changed the control valve,and the pilot flame looks to be around the tip of the thermo couple.the back draft is a hard call.
the problem seems to get worse the colder it gets out side and the heating system is running more.in the summer when we are only running the A/C we have on problem with the water heater. so we believe that the heating system is causing the problem but not sure how.
maybe that it charging the chimney or making to much draft and snuffing out the pilot, but I do believe it's some how causing
the problem,but how?

Re: imtermittent pilot lite

Just thinking out load here ....

Could be back drafting.

Guessing the A/C is tied into the furnace for central air?
If so .... then it's not likely an issue of the blower sucking the flame out.

Could be some unusal gas flow issue when the furnace is running . In other words ... the furnace will have the greater demand of gas draw while it's heating .... if the supply is restricted somehow the furnace will take all it can robbing the water heater if it has to .... just a guess.

Brooklyn Plumber
Re: imtermittent pilot lite

What type of heating system do you have in the house? If you have a forced hot air heating system do you have a return duct anywhere near the water heater? If so, is there adequate make-up air in the area for the return duct to pull? If not, the pilot may be getting snuffed out.

If heating system is other than forced hot air, ignore all of the above and I'll keep thinking!!

Re: imtermittent pilot lite

Because it only happens during the heating season my guess is that the draft from the furnace or boiler is causing a back-draft that is blowing the pilot light out.

Re: imtermittent pilot lite

Another thought which is kinda a wild shot, but something has to be causing this -

Try positioning yourself so that you can clearly see the pilot flame while neither the furnace or WH is running. Then have someone turn the thermostat up and watch the pilot. Does the flame seem to get pulled over any?

Although you said the "tip" of the thermo-couple is in the flame.....I'm not sure how much length that actually is. Point being, if only the very tip and the draft from the furnace pulls on the pilot flame.......it could be pulling it over enough to cause the TC to cool down. If it's windy outside also, the draft would likely be even greater and so it may only occur when windy.

IOW, it may be that the pilot doesn't ever get blown out, but rather the TC perceives that it is and so shuts down the gas supply. Then the pilot goes out. *If* this happening, the resolution might be to adjust the TC position so that more of it is in the flame all the time.

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