Replies

1. 
   Steve_Worcester | Jan 15, 2001 04:32am | #1

   *
   I had a similar problem that turned out to be water in the gas line.
   To check, try this. Turn on the furnace, and then have some one else turn on some other gas appliance. If there is water in the line, the surge to get more gas will pull the water with it and plug the line and the furnace will either dip down, or because it can't get gas, it will go out.
   The gas comany came out, and we had them check and it was indeed blocked. You could hear the gas surging.
   Solution was to replace the line

1. 
   Bob_Walker | Jan 17, 2001 04:14pm | #2

   *One (remote?) possibility is "back drafting" or lack of proper drafting.Assuming it's naturally aspirated (i.e., doean't have a draft inducer motor):1. Look up under the drafthood at the top of the heat exchanger. Is there a lot of rust in there?2.look around the bottom of the face of the heat exchanger and flame guard. Rust there? Swirl marks?3. Hold your hand next to the bottom edge of the draft hood as the unit fires up ("lights off.") Do you feel flue gases spilling out from the draft hood? Does it continue to spill after 1 minute?4. From a safe distnace, watch the flame during light off. Any flame rollout?If its a draft induced furnace, during operation check at the top of the chimney that it is actually venting. (I don't recall seeing any induced draft units with a standing pilot, but, ya never know....)Check for drip marks at the bottom of the flue and any flue joints, which can also indicate improper drafting by condensation of the water vapor in the gases before exiting the flue.Note, too high a draft in the flue can cause an "air curtain" effect in the draft hood which can block flue gases exiting the top of the heat exchanger into the draft hood, which backs up and causes problems with the flame and i possiblythe pilot.The only sure tests for venting is with a draft guage, but the above will give you some idea if the furnace isn't venting properly. It's not likely that any of these things are causing the pilot problem, b butif it is a venting problem, there is also a high likelihood of carbon monoxide posioning risks.

1. 
   Tom_Chew | Jan 26, 2001 03:17pm | #3

   *Scc: Try the simple things first.Clean Pilot Oriface. Replace thermocouple. There should be a nice Blue strong flame hitting tip of thermocouple. >>>>>What brand of Funace is it? Most manufactures had to install safety devices "ECO" Emergency cut-out switches that will Kill pilot lite if the flame rolls out, or the exhaust vent is blocked.

1. 
   Dale_Buchanan | Feb 04, 2001 05:45pm | #4

   *CC: Had a similar problem and found that the supply line was not producing enough gas to keep the pilot light lit during operation. When the burner fired up the pilot light was reduced to the point where it was too small to keep the thermocouple energized. Look for some debris in the fuel line. It's worth a try.

2. 
   scc_ | Feb 04, 2001 05:45pm | #5

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   I have a 10 year old gas fired furnace (hot air) and can't keep the pilot light on. Gas Co has been out 4 times and by now, replaced everything associated w/ the pilot light. Usually stays on for only 24 hours. The furnace is an a drafty garage. Only other symptom is it takes hours to warm up the small area it feeds.
   Any suggestions (besides a new HVAC professional?)

   thanks for the suggestions!
   scc