Vented Nat. Gas Fireplace Problem

[danadak426]

Have a 9 year old Superior unit; when burner lights flames only stay on appx. 15 minutes, then both burner and pilot light go out. Re-light pilot (stays on fine), but when burner starts, only runs 15 min and goes out again. Understand have a millivolt system - appears there's a thermocouople, pilot, and thermopile: which piece might be causing the problem, is it easy to remove/replace and how much would it cost, and is there a good internet site to hunt parts for a Superior unit? I've been surfing the internet and thus far no luck .... thx!

[Narroc]

1) Check that the Thermocouple is tight in to the gas valve if necessary remove and make sure there is no crud on the t/c end or in the valve refit and make sure it is tight but don't over tighten.
2) Check that the over heat stat is not operating and killing the current from the t/p to the valve.
3) Check whether the pilot is going out first or the t/c is turning the gas to the pilot off at the valve. Do this by carefully watching the furnace and IMMEDIATELY it goes out check whether the pilot can be relit without touching the gas valve.
(With a T/c you only have less than a minute) If it will relight then the flame is going out first. If you can't then the t/c is turning the pilot out. Watch for the main flame lifting the pilot off. Don't put your face down to close to the burner while doing this in case of a blow back which can take your eyebows or eyelashes off.
4) Any good gas supplier should have t/c just make sure you get the right length

[danadak426]

Thx very much!!!!!!

[JCA1]

Get a can of computer air cleaner, spray directly into the throat of the pilot, with the pilot off ofcourse, several times. Then relight it. If this dosen't work post back.

You don't have a bad thermocouple, if so it would not hold the pilot at all. However a dirty pilot will cause the flame to lift away from the t-couple with burner operation, and cause shut-down.

[danadak426]

Thx very much, JCA1 - I'll give that a whirl and let you know.