Igot a 1972 carrer furnace it catches fire at the spud part of burner I got 11.5 inch watter column preasure on line you can cut it off turn it back on and it burns good blaze looks good I need some comet on air ajustment or what might be causing this I have cleaned the burners , thanks.

How is your draft? I would check the chimney.

Has the area where the furnace is, recently been flooded by water?

I beleve chimney OK this furnice is a harzionel under the fioor furnice is about 6in of ground it is pretty damp under floor wood this cause this and what can I do abuut this. Thanks

If there is moisture in the gas valve then the valve may not be operating properly. It may have to be cleaned out or replaced. (if that is the only problem)

Make sure the air supply to the furnace isn't restricted.

igot a 1972 carrer furnace it catches fire at the spud part of burner i got 11.5 inch watter colum preasure on line you can cut it off turn it back on and it burns good blaze looks good i need some comet on air ajustment or what might be causing this i have cleaned the burners , thanks.

Are the burners made of stainless steel?

There may be a crack in the burner that doesn't allow the proper air/gas mix.

Let me give a little more history I don't believe I got any air blockage I got luvers on each side of furnice 6in wide 30in longe just hang on I got severl luvers on out side house they ar open in 1972 installed this furnice used it 7or 8 yrs installed wood furnice has not used gas furnice in 25 yrs I am 66yrs old taught I fix furnice for emericy if I got sick furnice had standing polit I changer gas valve and polit to spark polit and inatalled spark box furnace would catch fire at spud before I stop using it every one an a while when new it burned all right how hard should the air to ajust do you need any equiptment to do this .thanks for all your time.

The burners are black iron they look good just to look at them I cleaned all the little slots they have little cross folded pieces welded about 4in from spud from burner to the other is that where it lights from 0ne to the other I did not check if stpped up.thanks

Sometimes the burners can be removed and the inside cleaned out.

To whome it might concern ifigered out my problem everv one ask said I needed to have blue flame on burner what I figered out that I needed was a BLUE FLAME WITH 1/4 IN. YELLOW TIPS I used furnace for 2 days with out any problems if any one think I might have problem in future with this kind flame please coment.thanks for all the coments on bord .

It may be that you are better off leaving the air adjustment where it is now. Any yellow flame means incomplete combustion. This wastes gas and can deposit soot on the heat exchanger further reducing efficiency. Does the problem come back if you just inch the adjustment open to where the yellow tips go away? If so, as I already suggested, the furnace may not be getting enough air or the vet is restricted.

labman I would like to fix this I am pretty patient if you don't run out suggestions I ajusted burner where I could see little yellow tips 1/8 in. or less burner come on 2 or 3 minets later 1 burner would catch fire at spud if you adjust burner where no yellow tip is seen 2 or 3 burners would catch fire at spud semes to sensitive you said furnice might not be getting enough air how can I give more air or vet restricted I don't what vet is how can unristrect it thanks.

The vent is where the combustion gases go. You should have a metal pipe that comes out of the furnace and goes up through the house or over to the chimney. Newer ones are Type ''B'' double wall, but the older ones were just 1 layer of sheet metal. Mice or birds could have built a nest in it somewhere or some debris gotten in it. It must be clear. You can use a flashlight and mirror to check the chimney.

My crawl space is actually so tight, that I had to add a vent for my furnace to work right. As I think about it, likely you have the access to the crawl space open when you are adjusting the furnace and maybe the grill off, so surely it is getting enough air in.

Newer furnaces have a small blower to supply combustion air. Are you sure if your furnace has one, it is working properly?

Could the new gas valve be supplying too much gas for your furnace? I am not sure how that is controlled, a jet I think. I can't say how to check that either.

labman the vent or flue is open it is double wall 5in.on out side it goes all way to top of house it has got vent cap 3/4 in. slots it looks OK I have got 7or 8 8+ 12in luvers around house and they are open I have ben burning wood and den't care if I lost heat it little wet under house this furnice does not have a combuston air motor the gas valve has 1/2in. In 1/2 out 3 wires from spark box honeywell valve I got 113/4 in.on inlet side 111/2 in. out side water colem on pressure I just don't know what it is with yellow tips if you thank of any thing else let me know thanks.