Recommedation for a Suburban furnace for 70 Overlander

[Airwalla]

Hi all. Just got a 1970 Overlander. I'm in the process of getting it to a usable state. I have replacement water heater, Dc converter, DC distribution panel and fridge on its way. I am replacing all the water lines to 1/2 Pex. My question is about the Furnace. It's no good and I want the best replacement for my 70 Overlander. I read as many post as possible, but I don't really get a co census one the Suburban NT I need so I can just slot it in with minimal change on duct work and where it will mate to my existing vent height. Amperage draw would be a factor as I want enough heat cycling, but not so much it drains a battery quickly.
Dimensions of the existing appear to be: 14-1/4" W, 18" H, 22-1/4" D

Any suggestions as to a recommended model and/or a good place to buy online in the USA.

Thanks in advance!

[TG Twinkie]

I believe if you go to the Suburban web site you will find a table showing what replacements are available.
I am pretty sure you will not find an exact replacement. Some mods will be required.


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[68 TWind]

When I needed info when I was thinking of replacing the old NT in my 68, I called the factory in Dayton, TN. The gentleman I spoke with really knew his products and what would work in older Airstreams. That was several years ago so I don't know if the service will be a good now but I would give them a call and see what the folks that make it have to suggest.
I did not replace my forced air furnace and opted for space heaters as here in Mississippi we don't camp when it is really cold. So far we are happy as the space where the furnace was located serves as the storage spot for the microwave.

[dbj216]

I recommend the Suburban NT30 for your Overlander 27 footer. They are readily available and sometimes on sale. There is significant amp draw to run the 12v blower motor.

I have installed three of these furnaces in my two Airstreams. There may be height adjustments to match the furnace combustion air inlet, outlet piping to the exterior of the trailer. And there may be some ductwork to modify. Suburban requires 3 of the 4 round duct warm air exhaust ports are open.

I had significant modifications needed on my 66 Trade Wind including height, exterior skin, interior skin, and ductwork. I opted for under floor ducting as running ducts behind my limited cabinets would take too much room.

I think it was D&K in Indiana that makes and sells many RV ductwork "fittings" that will help match your existing ducts to a different furnace configuration. Their catalog is on line. They have 10 by 4 square duct to 4" round adaptors.

I have found the heating system in my Airstream leaves a lot to be desired. I have pretty significant temp variations between the furnace kicking on, and then shutting down, like 5 degrees F. And I have significant temp variation between my head and my feet while standing in the trailer, again like 5 degrees F. And the furnaces are noisy. But it's a camper!

Welcome to the world of vintage Airstreams and these Air Forums. Have fun with your Overlander project.

David

[idroba]

My opinion is that a smaller than original (in BTUH) furnace would work better for you. An NT 24 or even NT 20 would give you plenty of heat in Texas climate and would take a smaller power draw for the fan. BTW the number, 24, 20 etc is the BTUH rating in thousands, so a 20 is 20,000 BTUH burner capacity.

I replaced a NT 35 in my 310 Motorhome (31') with an NT 24 with very good results a number of years ago. Plenty of heat and I camped in it one night at 16 F. I think most RV furnaces are oversized.

Remember this is my opinion, backed up with some real world experience, but others may disagree.

[dbj216]

idroba makes good points. I'll bet some of my heating problems are related to the large BTU rating on the furnace. We are always looking for lots of "warm" in cold Minnesota. A good heater in a car is more important than the AC. So I tend to think bigger is better when it comes to furnaces.

I'll bet a smaller BTU rating, like the NT24 would keep you toasty in almost all situations you would likely stay overnight. It would have longer "burns" and might provide more even heating than my blow torch running for 5 minutes on, ten minutes off. I guess that's why HVAC engineers make good livings.

Anyway, your furnace replacement project will still be a significant project and a new furnace will still be in the $600 range.

Let us know how it all works out.

David

[mccrosti]

I have a 72 overlander that has a suburban NT 30 that will run you out of your trailer. But I am also installing a catalytic heater so I can boondock without running my battery down.

[Airwalla]

Thanks all. Great advice! I will let you know how it goes.

[Sodbust]

Airwalla

Call me old school but don't throw the baby out with the bath water.. Myself,, I love the older tech that once made America great and won both world wars.. If it did not work a slap on the side,, or some oil it took off and did its job and ran..

Unless your old heating unit is rusted out ,, or otherwise worn out I would sure look at a clean up and oiling.. Ours was not working but after digging out a mud dobbers nest in the fan,, and cleaning it runs like new again..

I just don't trust all the newer electro gizmos as when they fail,, its a puff of blue smoke and its a game over. In my 40+ years of farming,, 2/3s of my rolling stock is 30+ years old and the other 1/3 is all newer iron.. Guess what,, when the newer $200k tractor will not shift,, or steer,, or start I can always trust my $500 1960 Olver back up tractor to get the job done. Even after sitting for 5 months.. Sodbust

[TG Twinkie]

I agree with Sodbust.
I just finished helping my brother trouble shoot the problem with the Hydro Flame furnace in his '2000 SOB.
A bad connection on the circuit board plug was the problem.
I had access to a board tester. Which was a good thing. It saved on the purchase of a new board. Without the tester one could have laid out $100+ to replace a perfectly good board.
I am of the old school too. Give me a water heater and furnace with a standing pilot and I will be a happy camper.
At least with a bad thermocouple a replacement is low cost. Plus. You can get a replacement at a hardware store.


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