How do you light a furnace NT40? 1971 overlander

[u2bewell]

Such basic question but couldnt get it going.
Furnace seems to have an electronic ignition.
I can't find the turn off and on valve on the side of the unit like the manual mentions. I suspect this is not an original furnace??
Instead of the valve on the side I got a solid elbow connection to the gas line!
I got the blower going with the thermostat, the gas turned on at the tank but where do I light a pilot light?
With an electronic ignition is there no pilot light necessary?
If anybody knows the step by step ignition process that would be great.
I am new to my airstream although I owned it for a couple years and getting ready to live in it in th next few days so checking all appliances. Also is it possible to change a rusty lock emergency valve on water heater without changing the whole water heater tank?

Thank you so much for helping.

Elizabeth
elizabeth@u2bewell.com

[jim kolhoff]

Elizabeth. Don't know specifically about your 71 Overlander, but on my 76, there is a valve outside of the trailer, directly down from the input gas line. Its one of those 90 degree-turn things. Mine was hard to turn (out in the elements) but it worked.

Jim k

[brunoffrance]

Hi elizabeth;
Welcome in this marvellous forum, you are in the good place .
My Airstream is an Overlander 27' dated from 1971 so I think we have the same furnace.
At first, don't forget to open the gas bottle outside ( check if the arrow indicate the bottle you open ). Then NO outside valve to the furnace. There is one inside , on the right of the furnace, near the water pump, under the burners. Open it and go to the little box in the bedroom, on the wall that make separation with the bathroom.
This box allows you to switch on the furnace and to get the temperature you want....
Wait a minute and the furnace 'll start; You need the 12 V for your furnace runs.

That 's all and it's simple

Best regards from FRANCE.

[u2bewell]

Merci je vais essayer le coup de trouver cette valve.
Thank you I will try to find the darn valve ;-)

Hey Brunooffrance i am from Lyon but in Californie for the last 25 years. I would looove to bring my airstream back in France. I will check some of your websites when times allow. You got more pics of your airstream?
Thank you

Elizabeth

[u2bewell]

Solid gas line, no valve under the stove, neither sides of the furnace unit, neither the water pump.
I got gas on stove right above.

repair man cant come for 10 days... darn...

[azflycaster]

Do you have a small door on the front of the furnace? I open the door on mine, instructions on the backof the door. My pilot must be lite manually. Pull the knob, press the button. Hold the knob for 3 secondds after the flame ignites. You can see the flame f=through the glass window, also located inside the small door.

[Smokin Camel]

I hate to be a party pooper, but do you really want to trust a 36 year old furnace? Check you LP & CO detectors. I ditched my old furnace just because I would not trust a heat exchanger of that age. Check the heat exchanger for cracks or signs of metal stress.

My old NT furnace had a spark ignition button (like a cigarette lighter) that I could push, check & see if there is a long button?

Ask some of the RV techs on this forum if they would trust an old furnace! I want you guys around so I can read your posts

[u2bewell]

well, i discovered that the valve got removed and a solid elbow got put instead.
The furnace itself doesnt look that old and no there are no long button to push or pull. I suspect the unit got changed a few years ago. NT40 is it an old unit?
I will post pics of the set up later.
Regarding the rusty emergency valve in water heater, is it dangerous to ignore it?
I am so close to have everything working thats frustrating....
Thank you for trying ;-)

[CharlieE]

I think I remember that Propane is heavier than air. That's why gas detectors are located near the floor. Airstream used to install most elbows, Tee fittings and shut offs outside of the belly pan thereby reducing the number of potential leaks inside the coach. Originally shutoffs for furnaces, water heaters and refrigeraters were outside the belly pan I assume you already looked there for the shut off. I agree that you should carefully check the sealed combustion chamber for rust. It's not fun to wake up dead from carbon monoxide poisoning. I don't know of a good way to pressure test the sealed chamber, but you can at least do a visual check by removing the furnace unit from the case. Then turn it upside down and do a visual check of the bottom side of the burn chamber. Water gets into that from the combustion air exhaust and intake ports and lays in there to rust that chamber. If you don't feel comfortable doing that take it to a professional. You have only one life, don't give it to your trailer.

[smily]

I had the same unit.
If you open all gas valves, which I see that you have, now open the cabinet under sink, there is access door to furnace, open furnace door. There is a small round screw cap, looks like a cap to a can of brake fluid.
Remove this cap, you will need a long match. Then you will depress the lite valve and you need to get the match all the way in the hole to the pilot burner. You should see a thermocouple inside the hole. Hold the match to the pilot burner. When you have solid flame, close the screw cap and go to thermostat, you will hear fan kick in and a few moments later you will hear the furnace ignite. When you turn thermosta down, the burner will cease but the fan will continue to run until the furance has cooled.

Good luck,
Ken

[brunoffrance]

Originally Posted by u2bewell

Merci je vais essayer le coup de trouver cette valve.
Thank you I will try to find the darn valve ;-)

Hey Brunooffrance i am from Lyon but in Californie for the last 25 years. I would looove to bring my airstream back in France. I will check some of your websites when times allow. You got more pics of your airstream?
Thank you

Elizabeth

Hi elizabeth;
Sorry for your Lyon, if you were in France, lyon is the gastronomy capital .... and the food is really good .... to discover.
Pics and story about our A/S is there:
AIRSTREAM, HARLEY-DAVIDSON and The American Dream in FRANCE.

all you always wanted to know about an american french...

Bruno

[brunoffrance]

Oh my mystake!!!!!

I've just realized I've given you instructions for the heater and not for the furnace....
Sorry and all my apologizes....

For the furnace, I've kept the genuine one and no valve or faucet to open for the LPG. I don't use the pilot, just turn on the knob and I use a match directly ; that 's all.

I'm very confused for my last description error.

Bruno.

[wlj1943]

Hello all,
I am a semi-retired Engineer and restorer, and former RV tech, licensed propane technician, and Certified General Auto Mechanic.

I think using any of the old design Suburban NT furnaces is quite risky, without first a full dissassembly, cleaning and detailed inspection of the combusion chamber heat exchangers, cleaning and de-rusting fully of the cast irom burners, and my experience is most of the units I have attempted to restore are no longer safe to use from erosion and corrosion. There are few parts available, none from Suburban who obsoleted this furnace series in the early 1980's, likely because of more ridgid design standards and product liability issues. Some key parts that are no longer available can fail and pose a significant risk of leaking CO into the living space. These parts include the elastomeric boot ( read rubber or plastic) between the outlet and the inlet of the two blowers, the asbesteos seal for the discharge tube, and the combustion air intake rubber tube. When the boot ages or the elastomeric or asbestoes seals leaks, combustion air and heated discharge air could mix and allow for excessive CO buildup in the interior of the trailer. I beleive Andy from Inland RV did a post on ths back about 2001 or so, but I am not sure it is still in the archives. NOS boots and seals are near unobtainium, so my professional advice is to retrofit new heaters which are safer. It is possible to restore an old heater to near-new servicable condition, but it will never be as safe as a new heater because of the advent of consumer product safety legislation and newer regulatory ASA requirements and international standards requre safer designs taht do save lives. Also the gas valve and safety thermocouples should always be replaced as they are only designed for about 10 years of life (same is true of the ranges too).
Personally I do not want to subject myself and my family and guests to the risk that the older equipment present, but purests want to retain the old furnaces for the restoration value and originality.
That is my two cents and I probably offended all the Vintage Airstream Club members, but they have seen my post on this subject back in the 1990's
Warren Jones
WLJ1943