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View Full Version : My pilot light won't stay lit


wirepro
Nov 18, 2006, 10:29 AM
Help,I have two problems.. My upstairs furnace pilot light will light,and after holding down the pilot button for about 3-4 minutes(it says one minute,but it won't stay lit after only one)it stays,but will go out again in a day or two... The furnace for the downstairs won't light at all.. I can't afford a hvac service call,and I'm an electrican so I do have mechanical ability to fix the problem myself, I just don't know what to fix.. What are some things I should check or replace?

NorthernHeat
Nov 18, 2006, 10:34 AM
The upstairs unit sounds like the thermocouple, if you've rplaced it and it still won't hold it's the gas valve. I don't know about the downstairs, not enough information.

bj139
Jul 3, 2008, 02:33 PM
I had the same problem and bought a thermocouple. I should have noticed the flame was yellow and not blue as the previous comment suggests. When installing the thermocouple I used wd40 and a toothbrush to clean the pilot burner and fittings. Upon re-installation the pilot would not light (lubricant in pilot orifice?). I took it apart again. Why do you always have to disassemble and reassemble something you are fixing 3 times? I washed the pilot burner in soap and the remaining warm water from the faucet. There still seemed to be some carbon in a hole in the side of the burner. I took it outside to the hose and adjusted to a good jet and blew water through it avoiding pressure on the main orifice. I then blew it out with compressed air and reinstalled. There was now a blue flame not yellow. I temporarily reinstalled the original thermocouple and the pilot stayed lit. If you have a yellow flame try to clean the burner first. I now have a used good thermocouple for a spare and saved myself maybe $100 for a service call.

wmproop
Jul 3, 2008, 05:58 PM
Never cleaned one with soap and water but if it works,go for it,, the pilot will dry it out real quick

bj139
Jul 4, 2008, 06:38 AM
If the flame is yellow it is barely able to turn the thermocouple on. A little wind outside moves the flame a bit and the thermocouple turns off. If your flame is yellow, remove the pilot burner and clean it. I initially had another yellow flame out the air hole on the burner. This is a sure sign of clogging. The pilot needs air to burn blue.

jfgzo
Nov 23, 2008, 01:28 PM
On some related posts, somebody mentioned checking whether the flame is yellow instead of blue. I endorse that answer! I have two identical log sets, one of which lit fine. I was going to start exchanging parts between the units, but first checked this site. Sure enough, the one that lit fine burned blue and stayed on, and the faulty one burned yellow. I blew compressed air into and around the flame orifice and air intake, and, voilą, it now burns blue and lights fine. The yellow indicates a flame that is not hot enough to activate the thermocouple. Terrific tip!
Jim

neenie57
Dec 18, 2011, 09:00 PM
My flame is blue and it stays lit a couple days then goes out, there is no way air can't get to it