Why does my boiler's pilot light keep going out? archived

marken

Jan 20, 2009 at 4:38am

Weil McLain gas-fired steam boiler installed in 2003. It has a standing pilot light.

For EACH of last 3 or 4 years, I've had to replace (or have someone replace) the thermocouple. Last week I replaced it again (boiler was working in the morning, but when I got home after work, the temp was 51, so I suspect it had been off all day)

Now this morning, 6 days later. the pilot light is off again. I re-lit the pilot light, and it seems to be working ... but can anyone tell me what's going on?

happy_puppster

Jan 20, 2009 at 5:34am Edited

in MY case, I have a WIND issue, everytime(not too often) there is an unusual amount of gusty wind, my pilot goes out. cant offer any advise, just a possible reason!

also, if the thermocouple is getting too much flame, it can burn out prematurely and negate the pilot light!!!

Phil_Masucci

Jan 20, 2009 at 6:32am Edited

Chances are you may have a crack in the boiler that when it steams and the burner shuts off water drips down and puts it out. It is common you may want to have it checked by flooding it to see if it leaks.. Sorry for the bad news if so oh oh

It could also be a bad gas valve on the boiler.

mjc

Jan 20, 2009 at 6:42am

What Phil says is what it was for us, but our boiler was a lot older. fwiw, we had recently installed a programmable thermostat that may have been implicated. We couldn't see the water (evaporated) but finally heard it hissing when in the basement. Your situation sounds a little different though, with the multiple thermocouple failures. Could someone see that the tc was bad, or just assuming?

Good luck!

Phil_Masucci

Jan 20, 2009 at 6:51am

It is the first thing I do even if my customer says it was just done. It's the first step.

krnl

Jan 20, 2009 at 7:26am

When we lived in MIchigan we had ancient gas furnace (hot air) and, after some part was repalced we began to have problems. Like Happy Puppster, it was a wind issue. The repair person figured it out and made a little metal shield to block the wind from the pilot flame. After that, we never had a problem.

It seems odd that a boiler you installed in 2003 would already have a crack.

Good luck.

Phil_Masucci

Jan 20, 2009 at 7:39am

I agree but you never can be sure unless it is checked.

plungy

Jan 20, 2009 at 9:26am

When this problem re-occurs more than twice and there is no leak, as Phil described, we usually replace the pilot burner. Sometimes the orifice gets dirty or burned and it will eat thermocouples one after the other due to carbon deposits or over heating.

oots

Jan 20, 2009 at 11:11am

i had three thermocouples go bad on a pretty new boiler-once a year then two in one week. they were all "yellow"-brass??. the last one installed now about 4 years ago was "silver"-stainless??. no problems since. (knock on wood).

oots

cody

Jan 20, 2009 at 11:51am

We had a problem where a sensor in the furnace was reading "low gas" when there was no problem, and shutting the furnace down. We'd relight it, and it would go off. Turned out to be a quick repair of a small part and it wasn't very expensive to have done.