windymatt
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Hall GTC - not a trailer
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Post by windymatt on Feb 13, 2018 19:19:11 GMT -8
Hello all... First, my trailer is actually NOT a trailer, but a 1973 Hall GTC mini motorhome - but with an Airstream influence. It was designed and produced by John Hall, the stepson of Airstream founder Wally Byam, in the San Fernando Valley near his other venture, the Revcon motorhome. Hall, being used to Airstream technology, used a number of bits and pieces he was familiar with in the GTC - one being the Suburban NT22 C furnace. It has worked flawlessly in the past, but has recently decided to have pilot problems that have me thinking about maybe changing over to a modern NT30.... but the cost and having to pull the fridge are slowing me down a little. For anyone with experience with these buggers, here are the symptoms: Pilot will go out a few seconds after releasing the pilot button and sometimes refuse to re-light, even after holding the button in long enough to hurt my thumb. The pilot flame, when it works, is a nice blue and hits the thermocouple in the right place. I was thinking it was the thermocouple, but since the flame doesn't always want to ignite at all, I wondering if it might also be the gas valve itself. Hmmmm Have any of you had success in finding generic parts to fit these babies, or would I be better off to change to a new NT30?? I have lots of time and money invested in my vehicle in the 8 years I've owned it and want to keep it as close to original as I can without jeopardizing life and limb.  |
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Post by Deleted on Feb 13, 2018 19:58:49 GMT -8
Looks like a big Dodge camper van? Do you have photos?
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Post by vikx on Feb 13, 2018 20:48:59 GMT -8
Welcome Windymatt,
The old NT furnaces are really work horses and yours has lasted a long time. One issue that plagues them is burner chamber failure. Check the welds and metal for deterioration and holes. It it's good, you may be able to find parts.
Your problem may be the valve, spiders in the line or the orifice could be partially blocked. If the rest of the gas appliances are working, your regulator and gas lines are probably OK.
I would give it a thorough cleaning first; air blow the pilot and burners. Soak the orifice in carb cleaner but do NOT poke wire thru the opening, air only. Some valves can be worked on, but they are a bear.
If it needs more, remove the cover to pull the guts of the furnace forward.That's done by loosening the exhaust and removing a couple of screws. Don't forget to disconnect the gas line. Sometimes the exhaust is STUCK and it can be difficult to get the pipe to let go.
Hope this helps. Our member Trailertrasher may have parts.
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windymatt
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Posts: 3
Hall GTC - not a trailer
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Post by windymatt on Feb 16, 2018 12:09:57 GMT -8
Looks like a big Dodge camper van? Do you have photos? Kinda - sorta. It's built on a Dodge B300 cab and chassis with a factory (Dodge) extended frame and driveshaft. The coach body is outer and inner fiberglass shells with a foam core and steel frame members. The floor is also foam insulated. The interior has lots of teak trim over woodgrained plywood - no particle board at all, and all the appliances were top of the line back in the day. Like Airstream, it has a pull-out gaucho in an aft stateroom with a furnace duct that runs back under the bed where the water tank and pump system is are located. There are also heater ducts in the head, the main cabin and the stateroom, which is why I can't replace the furnace with a radiant heater. They put a lot of effort into cold weather design! I also had a Boles Aero Non Pariel for a few years, but the GTC is way better built. I'll attempt to attach a photo or two, but don't count on it!  |
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windymatt
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Posts: 3
Hall GTC - not a trailer
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Post by windymatt on Feb 16, 2018 12:22:19 GMT -8
Thanks for the advice! I had the furnace out a couple years ago to fix a noisy fan issue, but had no idea that the innards could be pulled out through the front! I looked at it this morning but still don't see exactly what screws should be removed to allow this to take place, but the thru-hull vent and exhaust tubes are no problem. But here's the latest..... I actually got it working again! Now the problem seems to be that the fan is making light contact or enough vibration when hot that the danged rattle is back. I tell ya. It seems to me that the heater box is getting hotter than it used to after I plugged a few leaks in the ducting connection at the base of the furnace. This seems odd to me. Maybe the flame is set too high?
In order to remove the furnace box, the fridge has to be removed to allow access to the rear mounting screws, so I'm not too keen on going through that little number if I don't have to.
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Post by vikx on Feb 16, 2018 21:01:50 GMT -8
It's been years since I pulled a furnace. There should be two screws going into the floor? Look around, there may be more. Also disconnect the gas line. That will allow you to wiggle the guts to see if they're loose. You'll have to unplug the wiring as well. Your press fit exhaust will come apart? That's rare. Here's a link to NT removal: www.loveyourrv.com/suburban-rv-furnace-removal/ It's not the same shape of furnace, but the basics are there. Google around, you may even find a youtube video. Here's a service manual: www.bdub.net/manuals/Suburban_Service_Manual.pdf The 22 isn't listed, but they are all very similar. 12 volt fans are notorious for failing, so your "new" one could be on the way out. The bearings wear and the shaft wobbles, causing the rattle. Good luck with it! |
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