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pbnjsellers · 05-04-2005, 07:28 AM

Hello all, I am always amazed at the wealth of information and support out there for us. We have the front furnace out of the 345 for bench testing, and find that the insulating material in the combustion chamber has deteriorated and is preventing combustion. I think I have located a source for the gaskets, but there is some confusion as to the model number. We have a plate which says DuoTherm L 801086; is it possible to gather the model number from the serial number, so we can be sure we are ordering the right parts?

Next comes the fun of disassembly and (we hope) an inexpensive repair as we pull this old furnace back from the brink. The rear has already been replaced with a Suburban. We think we will be turning them both on this coming summer on the planned cross-country trek with kids and dog. This forum boosts our hopes of having the trip (and others!) be a dream, not a nightmare. First up, this system . . . rest assured we will be posting more questions later!

swebster · 05-04-2005, 09:55 AM

pbnj - there should be a model number on that plaque. I found a few parts supplier online by searching on DuoTherm furnace. Might be worth a few calls to see if they can find what you need.

Also, your local RV Dealership should have either a Coast, DTI, or Stag Parkway parts system which can cross reference a lot of these older numbers.

FWIW - The furnaces in my 1986 345 are DuoTherm Series 9000 furnaces (model #90125-001).

pbnjsellers · 05-04-2005, 10:49 AM

Thanks, Steven, but no model number is listed, just the serial. We assume it to be the 900 series, if the figures on the original delivery slip are being read correctly. Have you (or has anyone else) had their DuoTherm(s) apart to this extent? Any advice on the proper procedure? We obviously don't want to take apart any more than is necessary, but whatever has to come apart; we can then order those gaskets if necessary (probably!) and have all of the parts together at once, rather than keep ordering two-dollar parts and shipping them separately, no?

swebster · 05-04-2005, 11:10 AM

I've only removed and bench repaired a Suburban furnace from a Monaco. They are not that complicated, outer sheet metal/ducting then an inner combustion chamber, regulator, ingitor, board, etc.

Couple of books at Camping World on this subject.

Also - if it's not out how do you know what's wrong? Could the "insulation" be a mud daubers nest or hornet's nest? Pretty sure there should not be any insulation inside the combustion chamber. I ask because this is what was wrong with my rear furnace.....hornet's nest. I was able to brush and vacuum it out from the intake and exhaust ports without removing the unit.

I would recommend pulling it as a unit, disassembling and taking lot's or in progress pictures.....much easier to remember how to re-assemble.

pbnjsellers · 05-04-2005, 11:34 AM

Sound advice, indeed! It IS out. At the moment, in fact, it's near my feet. We bench-tested it with a buddy of ours who is an electrical engineer, so we vetted all of the circuitry, blower, etc. and had both spark and fan, then returned it to the AS to find no ignition. Back out, combustion chamber apart, lots of white insulation material fused to inside the faceplate with the ignitor assembly. Turns out we can get the parts from rvdealership.com (so far) but I was wondering if anyone knew the proper sequence of events for disassembly. Husband is attacking it shortly with tools. It does seem pretty straightforward, and it's nice to know that whatever gaskets are needed, can be ordered. Let's hear it for keeping the original appliances working!

pbnjsellers · 05-24-2005, 08:48 AM

Okay, $120 in gaskets etc. later and much hand-wringing as the processes of disassembly and re-assembly occurred, back in and producing heat! Yay! We enjoyed a good two weeks of front furnace goodness. Now it has gone temperamental on us again, hesitant to fire up then producing propane smell while it is burning. Not a good feeling. Husband was in an SOB MH years ago which exploded, so is understandably squirrelly about this whole superannuated furnace to begin with. Looks like we are in for a Suburban; any resources on finding them on-line? Also, what to do with old Duo-Therm?

pbnjsellers · 05-24-2005, 10:41 AM

The underlying question here: ARE we in for a new heater, or is there anyone out there, well in this area (SE Pennsylvania), willing to bench-test this unit with any confidence that it can or should be put back into service? Or should we just play safe and take this for the furnace's circling the drain?