Sunbeem american standard pilot problem

[kdet9797]

hello to all members of HVAC mechanic. it goes like this. old and i mean old, Sunbeam/Am-standard dual burner forced air.
1 side functions fine all the time. the other side has pilot problems. it appears pilot goes out when burner flames out, i say on flame out cuz it wouldnt on ignition as flame would keep pilot lit? i have had utility out twice. pressures ok, they changed orifice and thermocouple. it worked ok for 2 weeks but now were back to the same old, same old.
maybe my ears and mind playing tricks but i seem to hear a "poof" when the burners go out but Not always. it also happens at varying times of day and outside temps.

last winter i spent miles up and down relighting the pilot, and thought the replaced parts would correct the problem - (a lot of peeps here in Detroit still have antiques so the utilities are familiar with them but it aint fixed)

was wondering if any suggestions b4 i call em again.?

thank you much

[Freon]

It's possible when the main burners are shut off there's not a clean closing of the burner flame and the mini poof is blowing out the pilot light.

When was the last time you had the heat exchanger serviced. Have you checked the flue and chimney for any obstruction. Have you removed and checked the main burners.

Poor air and gas mixing from the combustion chamber, through the heat exchanger and out the chimney could cause this poof.

It is also possible you only need to increase the gas flow to the pilot. There is an adjustment screw on the gas valve.

[kdet9797]

"Poor air and gas mixing from the combustion chamber, through the heat exchanger and out the chimney could cause this poof"
i truly believe that this is what is happening but-
it only happens on 1 side of the old gas hog. it has NEVER occurred on the other side


thanks for the reply, i know the exchangers havent been serviced, probably ever. but michcon/DTE gas has been out a dozen or more times over the years - the pilot and all they seem to do is fixate on the thermocouple and orifice. never mentioned anything about exchanger. they also said pressures were good. also no CO problems at all.

i would guess they should have adjusted the pilot the last time after replacing the orifice and thermocouple. both pilots appear to be of same size with a nice solid blue burn. the thermocouple they put in glows a hot red.

that being said, since its 1 side related wouldnt that rule out the flue/chimney? thereby pointing to the heat exchanger? do i have 1 exchanger for each side? what if my lame brain could ask, type of service is needed on these dinosaurs? what type of exchanger problem would cause this- crack? dirt? corrosion?

i have brushed out and vacuumed the burners and burner chambers.

thanks again

ps i know its hard to pinpoint just from what i'm writing but any suggests are appreciated

oh 1 more thing-what do mean by "clean closing"-- why would the one burner clean close and not the problem side

thanks again

[Freon]

By clean closing I mean there is residual gas coming from the burner, although that is not likely (assuming 1 gas valve for both burners). I do not know how handy you are but if it is possible to swap the burners and see if the problem follows the burner it would rule out the heat exchanger. I have a feeling the burner itself needs a close inspection and cleaning since the pilots seem strong. If there is an orifice that shoots the gas into the burner, check that the orifice is clean. The issue is what's causing the poof that blows out the pilot.

[kdet9797]

thanks- i'm pretty handy but leary of doing "too" much, particularly around gas where the end result of a mistake is well, NOT GOOD!
yes there is only one valve for both burners so i'll try and access the problem side burner to see if theres anything plugging up anywhere and check the orifice as well. after of course i shut the gas off and purge. i will check to see how "easy" a swap would be as i do know what you mean by the problem would follow. (changing burner not really an option cuz of age and cost). i did find this out and please dont laugh-- haha, cuz i am, the house was built in 46 and its still the "original"

if that dont do it, its a call to the pros again.

funny it hasn't "poofed" out since i started this thread, we've got some cold and serious wind on the way to Detroit so i'll see how it goes.

[Freon]

Much of how a burner functions is dependent upon the draft. Possibly the upcoming winds will eliminate the problem and give you a new clue... insufficient draft. Is there any type of damper in the smoke pipe