Gas and Oil Home Heating Furnaces - Furnace problems AGAIN

Replaced a thermocoupler two years ago. Replaced it again on Christmas Eve. And today (four days later!) the pilot is out again. Is it possible I bought a bad thermocoupler? I'll probably head to the hardware store to buy another one before calling a repairman (no money!). Am I wasting my time or should I just call a repairman? Is there something I can do to combat this problem? Is there a reason the thermocoupler keeps breaking? HELP!

Are you sure its the Thermocoupling? will the unit light now ? have you checked the pilot orfice? is the gas valve maybe getting weak? what about a blockage in the flue? How about a cracked heat exchanger? when does it go out?
First off try liting it again.. if it lights and will stay lite, start looking else where for your problem.. What brand of coupling are you using?

Thanks for your prompt reply. The pilot won't stay lit. I just bought a thermocouple from Waters True Valu Hardware store...like $6 or so. I don't know anything else about the furnace. Sorry I can't shed any more light into whats wrong. When I replaced the thermocouple on Xmas Eve the pilot lit right up and stayed lit. It's doing the same thing as before...pilot just won't stay lit.

Just realized you may be under the assumption that I've installed a new thermocouple today. Haven't yet...I'm at work so will take off on my lunch hour to do that and install it (something even this woman can do!).

Hi Deenas and r-12 guy,

I just wanted to pass on an interesting 2 stories that happened here recently. A guy I work with had the same problem, suddenly. 1 week ago after years of no problems. A heating guy fixed it by turning up the pilot gas pressure to the pilot light from 3.5 psi to 4.0 psi. His pilot would go out for hours, he would relight it and stay lit for 4 hours, then go off and on in an eractic pattern.

Do you think the gas company is having a high demand period that could be creating this problem for border line gas line pressures?

Thats my 2 cents worth.

Mark

Edited this message to add this followup:

I just talked to my friend and discovered that his pilot gas pressure only seemed to fix his problem. It turned out that the problem was fixed when the repairman was called back the next day and replaced the control panel for around $100 or so. I'm glad I cleared this up before everyone got the wronge information.

Mark

[Edited by Mark Chapman on 12-28-00 at 12:24]

Thanks for your input Mark. When I originally called a repairman about the thermocouple earlier this year he said it should last between 3-5 years. Said something about something burning too hot. Beats me! Anyway, I'll probably go buy another thermocouple and see what happens. I'm hoping I just got a defective one.

Make sure the pilot flame is bright blue and encompassing the tcouple.I think when all is said and done you will need a TECH to replace the gas valve.It is either shunting out or the magnet is weak.If you luck out the magnet can be replaced.PDF

I bought the termocouple at noon but can't get the old one out (not strong enough) so will have to wait till tonight and have someone help me. UGH! Yea - the pilot flame is bright blue. I tried lighting it again before I tried to replace it but when I let go of the button it turns right off. I went ahead and turned the gas off and will wait it out. I'm wondering if maybe the problem was the installation on the old one. When I installed one before I remember it being very loose. This one (which my boyfriend installed) is so tight I can't pull it loose. I'm talking about the end where the gas comes out that you light. Anway, I'll give it another try tonight. Thanks for your input.

Snug is all you need on these...Yes Gas pressures play a big part too...Had one yesterday where the Pressure read 11" wc but when started up it would fall too 0-1"..( for thoses not in the know its an L.P. system....the guys LP supplier came out and replaced a regulator at the tank and Injected????? something in the tank.... hes happy he has heat... here on the Delmarva peninsula it was cold yesterday...wind chill was bone chilling...and today looks no better...if you cannt get it with this part, call some one..