Water Heater Pilot going out

[kweiss]

About a month ago I did a warranty inspection on a home that had this problem this summer with water heaters located int he attic. The builder had said that the pilot went out because of the extreme summer heat and poor ventilation in the attic. They had then installed two power vents fans in the roof to better ventilate the attic.

I had never run across this situation/explaination before. The attic had been ventilated in typical fashion for our area - passive vents, and while that is not exceptional ventilation it is pretty standard for this area. It would be much better ventilation than say and older home with the tank in a closet that is not well ventilated. So I do not completely understand how the attic ventilation would cause the pilot to go out - I would think it was a different problem. In this case, obviously the builder believed this to be the cause and he spent money on a fix - ie he wasn't just blowing off the homeowner.

Yesterday I had another warranty inspection where the homeowner brought up this situation. In this case, the plumber that come out simply told the homeowner to put a portable fan in the attic blowing on the water heater. I did find that the exhaust flue was improperly installed in this case - the transition piece/pipe had moved and the unit was venting into the attic. I cannot say if this flue problem existed during the summer when the plumber came out.

I did tell this homeowner that if this was indeed the cause, the builder should do something more permanent than a portable fan. Again, the attic was ventilated in typical fashion and I would not have called it out as a problem.

I am curious if anyone has run into this problem, or can expand further upon the possible causes, solutions, relationships in this problem.

Thanks.

[David A. Andersen]

Kevin,

I have not experienced this situation but I can tell you what makes the water heater shut down.

Inadequate draft in the flue (insufficient height) may cause downdraft and blow out the pilot.

Inadequate gas pressure (a lazy pilot flame). Easy to blow out and produces insufficient heat which produces electricity to hold the gas valve in the open position.

Excessive heat on the thermalcouple can change resistance and the ability to generate millivolt electrical current.

As far as the ventilation, it would take a seriously tight attic to use up all the oxygen that the pilot requires.

Ventilation reduces excessive heat (but not a portable fan).

That's all I can contribute at this point.

[kweiss]

That mirrors my thoughts.

My first thought was down drafting of some type.

I suppose the excessive heat - thermocouple theory might work - but I discounted it because I feel like I would see it much more often. This setup with the unit in the attic and bare minimum ventilation (leading / contributing to high attic temperatures) is a common thing around here.

[lfoster]

Have you talked to the mfg of the water heater to see if maybe it is a manufacturing problem with a group of the product? Might be worth a call !

Can usually find the mfg install instruction online also, that would give the recommended draft height.

Just a thought.

[Eldon E. Holliday, Jr.]

General Electric water heaters were involved in a class action lawsuit a couple of years ago regarding a similar situation. You might try an internet search on your model for more info. I could also see a possible down draft explaination, but temp or lack of ventilation not so much. Keep us posted on the outcome.