Furnace problem

[ddsouth]

Hello to all! I recently became the proud owner of a 1973 Argosy 24 and while evaluating the trailer and systems, I've discovered a problem with the furnace. I can light the furnace, the pilot light will stay lit, but when I turn up the theromstat, the movement of air in the furnace blows out the pilot light. I read the instructions on the furnace (I have no manual) and it refers to incorrect operation if the pilot light cover and "air shutter adjustment cover" is not tightly secured. I have no idea what the latter is.

Any ideas will be greatly appreciated!

[Mike Lewis]

I would be suspicious of a cracked fire box. I don't think there should be any air coming into the area of the pilot that would blow it out.---- Pieman

[dwightdi]

Depends on the make of the furnace. Suburbans have two fans. One blows thru the combustion chamber the other end of the blower motor powers the fan that distrubutes the air throughout the Airstream. Only way I know to be really sure the firebox does not have a hole is to dismantle furnace and look. The coleman furnace does not have a fan for the combustion chamber and depends on natural convection. It has a large square box sticking thru the sidewall of the trailer.

[CanoeStream]

Welcome to the Forums ddsouth! Do a Search on keywords: furnace recall. DwightDI's suggestion is a good start -- there's something about a tube on the back that didn't hold up like they expected. There's a carbon monoxide risk unless checked out expertly. No, I'm not the expert but am glad you checked in here!

[ddsouth]

Thanks for your replies!

I failed to mention that the unit is a Suburban(I don't know which model).

[StingrayL82]

According to Ron, at South Jersey RV, there was a recall on the Suburban furnace, but I think it was in 1972, not 73. Still it's something to check into. I think it had something to do with the crossover tube? I went ahead and bought a new NT-30 to save from having an Airstream barbecue.

Frederic

[3Ms75Argosy]

Honestly, from my 76, the crossover tube was shot (and you can't tell until you fully pull the furnace apart). I was suprised my trailer didn't burn - or I didn't die of CO poisening. There is a "burn plate" under the manifold - my manifold had a couple of holes on the bottom.... which were burning through my burn plate. Again - couldn't tell until it was fully apart. My furnace was working great, until simular symptoms that you relate.

I think I'm worth $500.00 for a new one.
My 2cents.
Marc

[dwightdi]

Later model furnaces the other posters referred to do not have a pilot light. They have an electronic ignition. If you search for Suburban Recalls in the files you will find out which models have the rubber cross over pipe. I think it was later than yours. After than problem, they went back to metal cross over pipes so the new ones you buy are not a problem. The burnt or cracked cross over could allow some carbon monoxide to enter the trailer. If you do not really know what you are doing it is best left to pros. After all you have only one life and Campers World will likely only charge you $200 labor charge to put in a new $580 furnace.

[dustyrhodes]

I just pulled the furnace out of my new 77 Overlander. I didn't trust a 30 year old furnace in my home and I don't trust it in my Airstream either.

[3Ms75Argosy]

do a search for NT30 on the forums. It will give you some insight (or on furnace replacement).
Marc

[72 tradewind]

My furnace did the same thing until I adjusted the pilot to a slightly larger flame.

[BrianWSNC]

thank you Tradewind. I have the same problem, but I tried adjusting the pilot light and the screw doesn't do anything. it was too cold and i was too tired to remove the pilot light tube so I just gave up and switched on the electric heaters.

someone told me the pilot light tube is probably rusted up inside, causeing the flame to be too small and not heating the thermocoupler enough. I will replace it when I return there in a few weeks.