Furnace blows black soot

[Jas155]

I just got a 71 Excella 500 from a family friend and he was telling me that the furnace is blowing black soot out of the exhaust. He also said that to fix this the mixture needs to be adjusted. Is this like a torch or something?

[Lumatic]

If this is the original furnace when was it unused for a long period of time? I would suspect accumulated crud in the combustion chamber and ducts. There really is not a mixture adjustment. There are more cons than pros in trying to save a 43 year old furnace.

[Jas155]

Yeah I thought about that. How bad is it to change it out to a new more efficient one?

[Inland RV Center, In]

Originally Posted by Jas155

Yeah I thought about that. How bad is it to change it out to a new more efficient one?

Takes only a couple of hours.

Andy

[Lumatic]

It is not really that hard. Should take a day or so. Most people put in a Suburban NT35. You have to do a little fabrication to get the furnace to line up with the exterior intake exhaust holes in the wall and to connect up with the ducts. $400 to $600 for a new furnace. There are multiple old posts with instructions in the archives.

Another thing about the old furnace is it is very difficult, if not impossible, to find someone to work on them and parts are a problem too.

An easier solution is a wall mounted catalytic propane heater. This type of heat has no moving parts, is silent, is radiant heat so it heats people and objects facing it in a localized area, is less expensive, easiier to install, and needs ventilation. But if you just need a little heat in the morning or evening may be useful.

[Ultradog]

I have a 75 Overlander that about every 2 or 3 years I have to take the combustion chanber out and clean it as it gets all sooted up.
I clean it a bit with a stiff brush then blow it out with compressed air.
Takes about half an hour.
Good for another couple of years.
I use mine hard for a couple of weeks during deer season every year.

[Jas155]

Thank you the advice, I will most likely just replace it, but for now I would like to at least get it working if possible.

Ultradog - do you have some sort of instruction on how to do that?

[Lance M]

Hi Jas,
Old furnaces are not usually the safest of things to keep. If you want to keep the old furnace for a while, you should take the furnace out for cleaning and inspection. It isn't too very difficult. I've attached a manual that explains it all pretty well, including adjusting the air/fuel mixture. Please note that many of these old Suburban furnaces from 1966-1978 or so were recalled for a leaking air crossover tube. Also, make sure you have a working CO monitor/alarm as well. Good luck!
suburban_nt22_dynatrail_installation_operation_service.pdf

[Jas155]

Thank you Top. I will make sure to be careful. Like I said just wont to get it going for short term. Got other thing on this I need to worry about before I replace the furnace.