Furnace Trouble

[PotatoPeach]

My wife and I just bought a 1975 Excella 500 and I have noticed a problem with the furnace. The furnace will come on and the blowers are working well, but the thing does not get hot. The air that comes out of the vent doesn't seem to exceed room temperature. I took off the front panel and noticed that the main chamber will get fairly hot, the second one doesn't seem to get hot, but the third one gets warm and the fourth one gets less warm.

I noticed that there seems to be quite a bit of soot in the furnace. Do you think cleaning it out would improve the efficiency, or is the problem bigger than that?

I am hopping that someone can help me figure out what my next step should be in fixing this furnace. It is a 30,000 btu suburban furnace, and it may be the original one that came in the coach.

I will post a picture when I can, but it might take a week because the trailer is being stored 2.5 hours away on a relative's property.

[overlander63]

Did you light the pilot? Does it have a pilot, or piezo ignition? What condition is the heat exchanger in? Has the rubber exhaust gasket been replaced?
Last, if it is original, it is rapidly approaching 40 years old. A furnace can leak CO into the living space, and cause some really dire things to happen to you and your family. If it is the original, I would replace it, not fix it.

[Lumatic]

You will have a hard time finding a tech willing to take on the liability of working on it. Ditto on the safety concerns. Save yourself the hassle and replace it. Palomino RV was selling new NT35s for $300.

[Mike Leary]

Originally Posted by overlander63

If it is the original, I would replace it, not fix it.

Double ditto, it's not worth it to your health or your pocket book.

[idroba]

If it is sooty, it is not getting enough combustion air. Mud daubers, bad rubber crossover tube, rusted main burner, bad fan motor, lots of possible problems. Parts are hard to come by, and you will find that Suburban will not even support the recall parts on that unit anymore.

I concur with each of the above recommendations. Replace it for safety reasons. You will spend less in the long run and eliminate the worry about not waking up some morning.

[Mike Leary]

Being full-timers, I've spent a ton of money on the Suburban and it's multiple failures over the years. My real regret, is I don't own stock in the company!

[PotatoPeach]

Thanks you all for the replies. I was thinking I might have to replace it.

Overlander63, I think it is a piezo ignition. All I know is that I turn the switch on the thermostat and it automatically lights. I plan on pulling it out and going through it this weekend to check the exchangers and gaskets. If it looks bad I might just have to convince my wife that we need to buy a new one. I think having her read the replies to my question will help.

[idroba]

If it lights automatically with the thermostat turned up, it probably is a replacement furnace already. I believe when you take it out to look at it, you may find a date on it. I don't think any electronic ignition furnaces were made in 1975. If it is not too old, it might be something simple like mud daubbers nest inside, which could be cleaned out.

But, furnaces can be a real problem, so still consider a new one.

[Splitrock]

Originally Posted by lumatic

you will have a hard time finding a tech willing to take on the liability of working on it. Ditto on the safety concerns. Save yourself the hassle and replace it. Palomino rv was selling new nt35s for $300.

+1



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