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canine camp · 03-08-2008, 01:20 PM

Ok, I bought a compressor and blew this thing out. I wasn't able to take the actual burner assembly out, so didn't see the orifice itself. I just can't figure out how to remove the burner, though I tried. I did notice, though that in between the burner chamber and where it hooks into the exhaust/fan chamber, there is a rubber hose that has a crack in it, which then has a gap of about a 1/2 inch at the widest. Is THIS the problem with this not igniting, not having a sealed chamber? And, if it is, how can I seal this up without actually replacing this rubber deal, whatever it's called? Is it possible with liquid gasket, or something that can handle high heat, OR, does this need to be replaced entirely? If this is the problem AND it needs replacing, then I probably will need to take it in to have an RV center do it. I just can't figure out how this thing comes completely apart, and some screws are so rusted I'm afraid they'll break. I'm assuming that having blown it out with compressed air, this would have solved a clogged orifice, if that even was a problem. Any help from any of you will be very much appreciated. thanks!

canine camp · 03-08-2008, 01:23 PM

I just re-read the post advising me to REMOVE the orifice, THEN blow it out. So, since I cannot figure out how to get to the orifice, I'm going on the assumption that this cracked rubber ring deal is the problem. So, any help along that angle is what I"m looking for. If that's not what can prevent ignition, then I'm giving up and taking this in to have it looked at. thanks!

lewster · 03-08-2008, 04:52 PM

Just found this info that might affect your decision to resurrect your NT-22:

"Suburban initiated a recall for all furnaces made from 1966 through 1977:

Campaign : 77E-012 initiated summer of 77

Campaign : 81E-015 initiated winter 81-82

The furnaces were models NT-17, NT-20, NT-22 and NT-30 manufactured between 1966 & 1970 The serial numbers were 0064881 and lower. Also furnaces made between 1970 & 1977 except those with an "M" suffix, The serial numbers are: 0064881 through 0715865. The recall specifies:" if the model and serial number of your furnace falls within those noted, have it inspected unless you are VERY SURE the Suburban recall has already been completed on your unit. The furnaces in question have a rubber-like crossover tube that could crack. Extremely dangerous carbon monoxide would then be expelled into the interior.”

From your description, your cross-over tube IS CRACKED and while it probably is not the source of your non-ignition problem, I would highly recommend replacing your NT-22 with a new unit completely! I strongly feel that comparing the costs of repairing/restoring a 35+ year old furnace of questionable safety vs. replacing with a new unit is a no brainer at this point......................REPLACE IT!

Thanks!

canine camp · 03-08-2008, 09:06 PM

Thank you very much for that info. Apparently my unit was NOT ever taken in to get a new cross-over tube! But, as you say, this does make my decision simple. Now I just hope that the new unit doesn't offer me too much grief. Thanks again, I really appreciate you saving me some cash!

eubank · 03-09-2008, 11:31 AM

Durn. I was really hoping to see a solution here.

Lynn

lewster · 03-09-2008, 05:26 PM

Quote:

Originally Posted by eubank

Durn. I was really hoping to see a solution here.

Lynn

This is a solution Lynn. I can get behind the restoration of many items on vintage Airstreams, but when it comes to LP and your safety, furnaces, water heaters and other LP appliances that can rust and degrade over time (especially 35+ years) just do not qualify as suitable candidates for restoration in my book.

charles12 · 02-10-2010, 10:53 AM

I just purchased my second 31' 1973 Soverign sans the furnance. I bought my first 1973 31' soverign two years ago, in great shape, so I have some experience with vintage airstreams. The new rig has a univolt that was been by passed, plus an Onan generator. The generator is foreign to me. There is a control in the front console next to the radio/tape deck. NO manual, or reference in the AS shop manual.

The previous owner used only 110v shore power, which is my intention also, yet I am somewhat of a purist, so would like to restore to original for resale. Questions are; 1. What is best replacement furnace and btu sizing for 31'? The ducting is in place for the rear bath and bedroom., as is the external vent and cover. Would it be better to go 110 v? furnance? If the univolt is bad, what is the best replacement?. Any suggestions would be appreciated. Thanks

Inland RV Center, In · 02-10-2010, 11:41 AM

Quote:

Originally Posted by charles12

I just purchased my second 31' 1973 Soverign sans the furnance. I bought my first 1973 31' soverign two years ago, in great shape, so I have some experience with vintage airstreams. The new rig has a univolt that was been by passed, plus an Onan generator. The generator is foreign to me. There is a control in the front console next to the radio/tape deck. NO manual, or reference in the AS shop manual.

The previous owner used only 110v shore power, which is my intention also, yet I am somewhat of a purist, so would like to restore to original for resale. Questions are; 1. What is best replacement furnace and btu sizing for 31'? The ducting is in place for the rear bath and bedroom., as is the external vent and cover. Would it be better to go 110 v? furnance? If the univolt is bad, what is the best replacement?. Any suggestions would be appreciated. Thanks

Charles.

The correct replacement furnace is a Suburban NT-30SP.

Airstream has used a solid state 55 amp Univolt for several years, with excellent results.

Pure electric heat is not efficient and along with the fact that the heat must be circulated thru the ducts, so that the tanks are protected in freezing weather.

Andy

kmpro · 02-10-2010, 10:19 PM

I just recently purchased a 1984 AS model 310 Limited M/H. This is my 13th RV since 1969, so, even though I am new to this forum"this ain't my first rodeo." My furnace too was like the thread here blowing cold air and no burner. After pulling the furnace, I decided it was foolish to risk being carbon monoxided by a 25 year old furnace. My solution? Replace the 30K BTU with a new 34K unit(same size physically) and don't worry about dying in my sleep.

GoldFever · 02-26-2010, 10:38 PM

We've got a 1992 25ft Excella with an NT30K furnace. I've had the furnace out before to get it to work...blew it out, made sure sail switch worked, etc.
It started 3 weeks ago after I put in a new thermostat but now the blower goes on strongly but the pilot won't light. Thinking about removing it again and trying to figure out what's wrong this time. However, I'm not exactly thrilled with doing this again. It is a 6.5amp, 1988 model furnace. I'm inclined to go with a new unit but here is my problem: There are three (3) exhaust openings for this unit, two stacked on the right, one even with the other side top tube. There are two mud dauber screens covering these openings to the outside world.
The Suburban NT-30SP has two exhaust openings and they seem to be near the center of the back of the unit and would not fit in the space because of plumbing behind the cabinet wall next to the door.
So my question is what unit can I use to exactly replace the old unit? So far I have not been able to find one that wouldn't require lots of work to move pipes, ducting, and cutting more holes in the aluminum skin (which I will not do).
Sure wish there was an "exact" replacement so I could pull out the old big amperage and noisy unit and put in a low amperage and quieter unit.
Suggestions welcome. Finding a solution priceless....
Gary in Hemet, CA

GoldFever · 03-09-2010, 09:40 AM

Removed the old controller board and had it tested. Result: Not sending a signal to the ignitor so I bought a Dinosaur Electronics Universal Ignitor Board, Model UIB S.
Installed it and still no flame.
Pulled the sail switch out (previously just blew it out with high pressure air) and noticed that the push pin switch was not springing back out so was not making a clicking noise...as it should. Voila!! Go buy new switch. Installed this new switch and it now works every time. Over the last few days I take a detour to the trailer and jump in and push the lever over on the thermostat. Sort of sneak up on the furnace at random times to see if it works. It has worked each time. I think the problem is solved.

Mike Leary · 03-09-2010, 10:06 AM

Quote:

Originally Posted by GoldFever

Removed the old controller board and had it tested. Result: Not sending a signal to the ignitor so I bought a Dinosaur Electronics Universal Ignitor Board, Model UIB S.
Installed it and still no flame.
Pulled the sail switch out (previously just blew it out with high pressure air) and noticed that the push pin switch was not springing back out so was not making a clicking noise...as it should. Voila!! Go buy new switch. Installed this new switch and it now works every time. Over the last few days I take a detour to the trailer and jump in and push the lever over on the thermostat. Sort of sneak up on the furnace at random times to see if it works. It has worked each time. I think the problem is solved.

What is a "push pin switch", I'm having similiar problems. Got a part #?

GoldFever · 03-09-2010, 10:08 PM

Actually I was referring to the little pin that gets shoved into the body of the sail switch. The new sail switch I bought makes a click when the metal "sail" moves toward the switch body. The "push pin switch" is supposed to have a spring action, pushing it back out and at the same time makes the clicking sound when you release the sail. Mine did not click and usually just got stuck in the "in" position.
Sorry for the misunderstanding here

Part number? The guy at the trailer supply nearby went over to the wall with all the Suburban parts hanging on it and found the one that looked just like the old one except it was white not black like the old one. He said if just needs to be the exact same size and design as the old one....which it was...and it works perfectly.

Hope this helps.

Patricia720 · 07-25-2013, 08:01 PM

I've referred to this string several times and it has been very helpful. I was having the same problem with the furnace in my 2003 Safari and it proved to be the sail switch. I had it replaced by a mobile RV repair guy, since I was on the road and did not have the time to wait for a part in the mail. The furnace worked well for about two weeks and then the same thing started yet again. By "same thing," I mean the blower motor comes on and runs for awhile but there is no ignition. I'm in Arizona all summer so it hasn't been a big deal but the problem is rising to the top of my To Do list. Any ideas as to what is damaging the sail switches? Or do you think it's a coincidence that two died in span of two weeks?

eubank · 07-26-2013, 08:14 AM

Dust is the enemy of a sail switch. I've fixed or replaced ours on a number of occasions, several times by simply taking it out (no easy task) and giving it a good blow-out with compressed air.

On the most recent occasion, I replaced with a new one that had been sitting in its shipping box for several years. Interestingly, the manufacturer had slightly redesigned the switch so that the sail is slightly larger, making it easier for the blower to move.

Lynn

Patricia720 · 07-26-2013, 11:14 PM

Dust eh? That makes sense. Thanks for the input. When I dig the bugger out I'll try to figure out how the dust is making its way in and if I can prevent it.

Patricia