pilot light won't stay lit
#1
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pilot light won't stay lit
14 year old gas furnace. It was running fine Had my regular guy give it the yearly check over like i've been doing for 14 years.I believe in building a good relationship with my home repair guy - learn a few tips and keep everyone employed.(I'm a female).A week later the pilot goes out.Strange but i re-lite it. 5 days later again.do the same.Third time I call. It a Saturday so a call out guy comes looks it over and says"pilot flame lifts off burner side provides flame but gas builds and ignites when call for heat".Pressure 3.5 outlet. but needs a new pilot assembly. He doesn't have one but will be back Monday. He did re lite it. Monday install new one 4pm At 2 am 55degree lite out. Any suggestions?
#2
Im not an expert on gas systems but here are my ideas. If a new thermocouple was part of the pilot assembly, that eliminates that. If not, it should be replaced because it is expendable and inexpensive. It is possible that you have a sticking house regulator. It may only stick once in a while. Possibly the vent is clogged. I believe the gas company would be responsible for checking that. The gas valve on your furnace could also be at fault but I can't tell you exactly how to check it out. I'm sure one of the gas experts will come by here soon with more info.
Good luck.
Good luck.
#3
Join Date: Aug 2002
Location: Mountain Williams Missouri
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Id ask why new pilot assembly. If you clean the pilot and new T/C.does the pilot cover the T/C, good flame on it. Dont know where you are but 3.5 W/C is low here for NG. I have seen it when its cold for so long the gas psi goes down and some burners start to act up.
ED

#4
Ed,
I think she meant the gas pressure after the main gas valve on the furnace.. 3.5 is what you want..
Stock,
Did they replace the thermocouple? If not, you can easly replace it.
I think she meant the gas pressure after the main gas valve on the furnace.. 3.5 is what you want..
Stock,
Did they replace the thermocouple? If not, you can easly replace it.
#5
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Jay
The gas pressure for nat gas or LP should be taken on the manifold there at the burner. With all other gas unit on at that time. I dont know of any where that the gas is down to a 3.5 for nat gas . Most of the time it will be 4.5 to a 6.0. But Id ask the gas company there what they say they have in the lines or should have. Also here we have again if the regulator is out side . Did it get covered with snow. This will do it to you when the regulaor cant vent right.
ED

#6
Pilot Light
I had a customer years ago rang that her furnace fan kept going on and off and there was wasn't much heat from it.
Went around the next day couldn't find anything wrong with it good gas pressure
etc. Rang a couple day later 8.00pm same again next day nothing wrong, so told her her ring me if did the same again when it was going wrong.
Couple day later I got a ring so I shot around, 1.6"at the furnace 2.3"out at the meter. Gas authority said the next day quote 'yes we have a problem with low gas pressure on hi demand in that area we're working on it ' Appeared the whole street was down in pressure in the evening when everyone turned their heaters up.
Went around the next day couldn't find anything wrong with it good gas pressure
etc. Rang a couple day later 8.00pm same again next day nothing wrong, so told her her ring me if did the same again when it was going wrong.
Couple day later I got a ring so I shot around, 1.6"at the furnace 2.3"out at the meter. Gas authority said the next day quote 'yes we have a problem with low gas pressure on hi demand in that area we're working on it ' Appeared the whole street was down in pressure in the evening when everyone turned their heaters up.
#7
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Im with Narroc all the way here for sure. many years back White Rodgers had a gas valve that the gas pressure helped to open it. When it got real cold and we went on no heat calls it would be the furnace had that valve on it and the pressure would be down in the gas line. So everything was ok on the furnace and worked. It just had to have gas with some pressure behind it
I see St Louis Mo there. " ha" thats where this all happen way back. Also the lines do get a rust in them and that can build up some times . Thats why you have a T trap there by the furnace to try and catch this rust powder like . I think the gas lines in the county where just a little bit higher W/C than the city was at that time.
ED
I see St Louis Mo there. " ha" thats where this all happen way back. Also the lines do get a rust in them and that can build up some times . Thats why you have a T trap there by the furnace to try and catch this rust powder like . I think the gas lines in the county where just a little bit higher W/C than the city was at that time.

Last edited by Ed Imeduc; 02-03-04 at 02:11 PM.
#9
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New gas control value
The guy came and looked at the pilot light and says I need a gas control value. Just before it is kicking on(lighting up burners) it is making an exploding sound and shooting a flame. It doesn't do it each time though and the pilot light is staying lite. He said the gas control value is $225 does that sound high This house has a standard furnace 14 years old 1250 Sq. foot house.
#10
Pilot Light
Sounds like there is delayed ignition and the pilot is not positioned in the right place to light up straight away.
The valve must be allowing gas to go in and build up for a flame to light late and make an exploding noise,
Before getting a new valve get the pilot to be repositioned. Could also (more Likely) be that the burner could have a bit (or lot) of scale fallen down on top of it or might need a good wire brush clean. This can stop a clean take off from the pilot. However as a new pilot assemby has recently been fitted the burners must have been removed anyway and should ? have been cleaned so I would also check that the crossover wings on the burner(s) are lining up.
It is very rare that valves give poblems. I renewed a 24v Honeywell one on a 30yrs old Coleman furnace a few months ago as the flame failure was leaking and not shutting off.
The valve must be allowing gas to go in and build up for a flame to light late and make an exploding noise,
Before getting a new valve get the pilot to be repositioned. Could also (more Likely) be that the burner could have a bit (or lot) of scale fallen down on top of it or might need a good wire brush clean. This can stop a clean take off from the pilot. However as a new pilot assemby has recently been fitted the burners must have been removed anyway and should ? have been cleaned so I would also check that the crossover wings on the burner(s) are lining up.
It is very rare that valves give poblems. I renewed a 24v Honeywell one on a 30yrs old Coleman furnace a few months ago as the flame failure was leaking and not shutting off.
#11
I'm leaning with Narroc on this it sounds like your burners need pulled and cleaned. Esspecially the cross overs where spiders like to nest. That explosion is probably blowing out your pilot light. I might try a differant hvac contractor for a 2nd opinion on this as delayed ignition is very dangerous and a parts changer is not what you need. 1st he wants to change the pilot assymbly now it's the gas valve. He may be capable and without being there to check it myself it just don't sound right.