furnace help needed.

[william]

I have a janitrol gmp075-3 that is acting badly. A week ago, in the middle of the night I noticed that the fan was running continuously, but the gas would only stay lit for a few seconds and then it would go out and repeat again. I turned it off, fiddled about for a minute or two, and it started working correctly. The next night the same thing. The night after that, fiddled again as usual(though I suspect it was just the delay resetting something) and this time nothing. Won't even let the gas start. Left it off over night, the service man comes in the a.m. blows out the vacuum line, and it starts working. The next night? It does it again. Nothing in the vacuum line. I turn it on, it clicks, a few seconds later the pilot strip glows, hear another click, and it fades...only to try again in a couple minutes. Do you guys have any troubleshooting advice for a pretty cold fellow and his family?

[Hube]

William; Since you had this service guy out a day or so ago, you will be best to get him back immediately as he should now have a real good idea of what is wrong. It will be less costlier too. Let us know how you make out, Hube

[william]

I had him return on a callback, no charge. The visit before, I had told him that I had problems with the rollout switches in the past but he shrugged it right off. Thanks to the forums and some reading had narrowed the problem down to between the board and the valve, which left some switches and the vacuum switch, etc....Sure enough, he bypassed the rollout switches(I thought it was the problem, but I am leary to bypass anything on a device that can potentially explode) and it fired right up. From now on, I'll trust my intuition and then find out how to test it...and move on from there.

[Joel]

If the rollout keeps going out (once may just be a down draft )but if it goes out repeadedly there is a problem in the venting and it may be spilling fumes into the house you should not operate without the safties atattched this may also push your flames back and burn youwireing ect.

[william]

He bypassed to check it, they're replaced now.