I have a natural gas fireplace.
The pilot light will not stay lit, well, you can light it
and turn up the thermostat. The fireplace will burn for
20 minutes or so, then go out.
Any ideas before I call the professionals?

 

replace the thermocoupler its the thing that the pilot flame keeps warm very common thing to go bad most hardwear stores will have them thay come in diff. sizes so you might want to take a measurement if that dont work call heat and air dude

 

Yeah what he said, suggestion... take the old one with you, it is a small coppery looking tube with a small thin tube running from it up towards thermostat, that way when ya get to the store and they ask what size ya can show em..... sure beats standin there with a miffed look on your face

 

Ditto.... sounds like the thermocouple/pilot generator. $3 part 10 minute job. You may want to also check and see if it has any sensors like a vent safety switch or high limit switch. More likely than not it's the thermocouple.

 

Might not be thermocoupling.Get a straw with the end that is flexable and usally you can clean them they get pretty dirty all you have to do is blow down in thermocoupling and that should fix the problem.

 

Yeah, what he said, try a good ole pipe cleaner first. They get dusty and won't keep the flame.
As with any possibly mal-functioning gas appliance, I would also suggest getting (if you don't already have) a Carbon Monoxide Dectector, it kills over 500 yearly in the U.S.

 

If none of that works you may have a faulty <gasp> gas control valve. Do you have any paperwork on the fireplace? It could be a safety sensor. Some have them some don't. Does it have a thermostat?

 

Just out of curiosity, just before the flame goes out, does the flame change color? Does it turn real dark blue to the point of being hard to see? How long has the fireplace been in? I don't really think it is the thermocouple if it will burn for twenty min. then go out. Check the venting on it. You may have a leak in it that lets the fireplace recirculate the combustion gasses and it just plain runs out of oxygen. That happens more than you think. Let us know.
Tom

 

good point mn... not to mention the buildup of carbon monoxide if the vent isn't working properly. Do you have a clamp on the vent flue damper to keep it from closing?

 

Depending on how old the unit is, it should cut off if the oxygen level gets too low. Saftey feature for removing too much oxygen out of a room.

How big is the room your heating?

 

Thanks guys!!
I did the ol'Pipe Cleaner trick and got lucky right off that bat.
It fixed it!!
Thanks again

 

Cool deal. Sometimes it gets the white crusty stuff on it and won't read properly.