Help

ThermalJake

Okay, I have this old Miller furnace in my trailer. It is an atmospheric LP burner from the mid-1980's. I posted a question about the air adjustment the other day, but without response. My teacher in Heating 101 suggests that I convert it to an oil burner or a power burner (if for no other reason than the parts are available for it). My supply house was little help when it came to atmospheric burner adjustments (I guess they are rare nowadays). He gave me the tech #, but they said that the air is factory set and non-adjustable. This seems odd to me, but I am a novice. Is it really possible to have no air adjustment? I could easily convert to a modern LP power burner. I could also get an oil tank and easily convert to an oil burner. So I have two questions:

1) Does anyone know anything about these atmospheric burners?

2) Should I convert to the power burner or go all the way and convert to oil?

Thanx

Jake

Mark Hunt

Coupla' questions.


First, are there no air shutters on the burners?

Second, I did not see your other post and maybe the answer is in it but, why do you need to adjust the air?

Third, Do you have a combustion analyser? I would not recommend playing around with the air adjustments without one.

I used to work on lots o Miller furnaces, if you post the model # I might have some old books lying around.

Mark H

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John@Reliable

What to do?

Consider this most trailers don't cost that much to heat,so figure out the cost of both and appox. fuel costs of each to give you a good idea which way to go.

ThermalJake

Hi mark and John,

I posted something below, I think that the subject is "CMF80-AG". It should fill you in. If not, I'll respond back after I check for my old post. Thanx,

ThermalJake

Found it below

I did find it below, and I can fill in any more details needed, but if you used to work on these things, then you are the guy that I'm looking for. It is atmospheric, so it has no shutter. Anyway, let me know.

Thanx
Jake

John@Reliable

Is this of any help?

The normal excess air for atmospheric burners is about 25%. Gas Power conversion burners will be a little less about 18 - 20% excess air. Some real old systems (atmospheric) may be as high as 35-40% with CO2 8.5% O2 6%.

ThermalJake

The problem is....

that after the cleaning, I checked the fire by sight, and it was coming out of the firebox about 6 inches. There is no shutter, and no venturi. I cannot figure out how this thing is supposed to be adjusted. The guy from tech support told me that they are adjusted from the factory, and there is no way to adjust the air/feul in the field. Can he possibly mean that when they go out of adjustment, you just throw them away? It has a "Unitrol" gas (LP) control which brings the gas down about 6 inches into an ell with an orifice, and then has about 1/2 inch space before the air tube brings the feul/air into the burner. If this was a stove, the 1/2 inch space would be where one would find the venturi with the set screw. This has nothing.

Hey Mark, does any of this sound familiar, or should I borrow a digital camera from someone?

The real reason I was thinking of changing the burner is because I cannot find anyone with information on this one, and I could build a newer one in my burner school with almost no cost.

Thanx again,

Jake

Mark Hunt

Off the hip


I would say that the gas valve is acting up. You could check the incoming pressure, but it sounds to me like the valve is about to give up the ghost.

I will dig out my Miller books, but I think I know which model you are talking about.

Check the manifold pressure. I'll bet that is where the problem is.

I'll be digging out my old service books in the mean time.

Mark H

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ThermalJake

Thanx

My wife is yellling for quality time, so I'll check in again tomorrow. Thank you for your help