Suburban NT-12L and 16L furnaces

[slugbugrichard]

My first post to this group:
Does anyone know what the difference is between the NT16L(NT12L) furnaces and all the other variants of the NT16 and NT12? I see NT16SE and NT16M, etc. etc. on the web. I cannot seem to find much internet info on the "L" suffix models.

I have a 1983 38' coach my father left to me - Dr. DuBose.

[chockwald]

Steve Ward (Prarieschooner) will probably have some info for you. He's had to fix a couple of his.

[prairieschooner]

I'll have to check but if I am remembering correctly it is the size (BTU) of the the furnace. I have the manuals with us so I'll check it out later.
What are you looking to do? I have been intimate with my furnaces. I serviced all three of the last year replacing parts such as the circuit board, fan motors, temperature shut down switch. I found that these parts were readily available but I was using the part numbers for newer units.
Look through all of the manuals in the coach. I found ours at the bottom of a locker with misc. other items on top of them.

[slugbugrichard]

Thanks, Steve, for your reply.
I have 2 of the either NT-12L or 16L ( I have not pulled them out yet to see the name plate). One has a screaming fan and the other is going that way. Both have the large yellow flame that is described as "bad" in the Suburban user manuals.
I also have one NT-24M that draws 15 amps on startup, so I am guessing the fan motor is locked up (no fan sound).
The plan is to pull each one and do a dis-assemble and inspection. I am an electrical engineer so the electronics should not be a problem - the mechanical I think I can mange as well.
The real gist of my original question is what does the "L" suffix mean? If I search the web there are no documents for the "L" versions, although I have have the user manuals for them.
I am looking forward to getting these babies out on my bench to see what is going on.

[prairieschooner]

OK the NT-16L is a 16,000 BTU input / 12,000 BTU output, while the NT-12L is 12,000/9,000. We have the NT16L and I would expect you to have the NT-16L, there is a model/serial tag on the unit although you may need to pull it to get those numbers. These units are Suburban Dynatrail models. The L may be a designation for LPG since they are designed for Propane (LPG) but I am not sure about that at all.
I replaced the Fan motor on one of mine last year. The old Number for the Fan Motor was #220634 but cross referenced to a replacement #2-520950. You should get a replacement "kit" because it has the Gasket needed. Be careful when pulling the Unit because there is a SCREW from the OUTSIDE, otherwise pretty straight forward. Remove the Gas Line, Rear Screw, mounting Fasteners and the wires (2 for the Power and 2 for the Thermostat). I Pulled the Housing on the forward unit but left the Housing in place and slid the unit out that is under the Fridge.
I tried to clean and lube the fan motor but don't bother, it didn't work very long. You may need to be patient with the Squirrel Cage that is inside of the Housing. The Set Screw on mine was stubborn, I had to drill it out to save the Squirrel Cage.
There is a Switch for the NT24-M that tells the unit that it has cooled down. This little switch was only about $20.00 or so and I would recommend that you replace it if you have to pull that unit out as well. I believe that I left that Housing in Place as well.
The reason for leaving the Housings in place if possible is to keep the Ducting in good condition. You may also need some good Duct Tape just because the old stuff would have dried out.
Good Luck.

I forgot to tell you about the burner. I cleaned ours with a stainless steel "toothbrush" size brush. The LPG Gas left behind a residue, no big deal.

[slugbugrichard]

Thanks for that detailed reply.
So by "leaving the housings in place" you mean to leave the exterior housing (cover) bolted to the floor, but pull the guts out after the 3" screw is removed and gas pipe disconnected? My ducts slide up and pop out from both sides of the unit, so the ducting is not too compromised.

[prairieschooner]

I had to pull the exterior housing on the unit under the couch. Afterwards the ducting needed to be re-taped in numerous areas because the adhesive on the tape had dried out. Much easier to leave the others in place.
There are also some fasteners that hold the "guts" in place (I think 2)

[slugbugrichard]

Well I got the one furnace out from under the couch. Had to remove the couch to do it, but I was really impressed at how Newell designed cutouts in the couch wood framing to allow removal of the 4 bolts holding the couch mechanism in place - well thought out.
The furnace unit has a name plate, but no model or serial numbers - just a rating of 2.8 amps draw. This could be a 12L or 16L. This weekend I'll be putting the unit on the bench to fire it up (no pun intended).
Thanks for your ideas in this thread.

[rodey]

Thanks for all the helpful "been there-did this!" suggestions. I took the burner out and cleaned it with a hack saw blade, then brushed it on a steel wheel...now it works! Took the burner fin, which broke in the process, and wedged it back in with a piece of steel. What ever makes it work...especially in northern Wi! Rodey

[prairieschooner]

Rodey, Just for SHITS (http://en.wikipedia.org/wiki/****) and Giggles please install a CO Alarm, please!

[rodey]

Have one!....and it works! Thanks for the suggestion. PS...69 Firebird 400 conv..86 300zx..88Jeep wrangler..82 Newell..Never lack of something to do!