Dead furnace |
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sammycamper
Senior Member Joined: 23 Oct 2012 Location: Minnesota Online Status: Offline Posts: 111 |
Topic: Dead furnace Posted: 23 Feb 2014 at 10:52pm |
Sam
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2012 rPod 173
2008 Trailblazer 4WD V6 |
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Tars Tarkas
Senior Member Joined: 14 Jan 2013 Location: Near Nashville Online Status: Offline Posts: 1447 |
Posted: 23 Feb 2014 at 10:33pm |
The job wasn't so hard. Diagnosis was time consuming, mostly because I really didn't know what I was doing. Other than that, pulling a wire was all there was to it. That meant taking off covers, vents, even some paneling, along with the inside cover of the air conditioner. (I did other things that were unnecessary for the job that I did because I didn't know what I was doing.) Then there was the rolling around on the floor and sticking hands and arms in little holes while trying to focus a flashlight on a little brown wire. It terms of the effort involved, there was about as much time and energy involved in my cutting grass.
Sam -- Your idea makes sense but it doesn't match the situation. The pod thermostat, mine at least, is like the one at your house. There is a toggle switch on the thermostat to choose Cool, Off, Heat. There are no controls, other than opening and closing manual vents, at the air conditioner or the furnace. I tried, but not too hard, to figure out where the break in the wire was. I think it was in the middle of the chase between under the sink and under the bathroom. That seems very unlikely though, but I still don't know haw the wire would get cut anywhere anyway. I thought a loose wire in a crimp nut or at a ground would have been much more likely. TT |
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2010 176
FJ Cruiser |
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sammycamper
Senior Member Joined: 23 Oct 2012 Location: Minnesota Online Status: Offline Posts: 111 |
Posted: 23 Feb 2014 at 9:49pm |
Sam
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2012 rPod 173
2008 Trailblazer 4WD V6 |
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techntrek
Admin Group - pHp Joined: 29 Jul 2009 Location: MD Online Status: Offline Posts: 9062 |
Posted: 23 Feb 2014 at 7:55pm |
Glad to hear the problem is solved.
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Doug ~ '10 171 (2009-2015) ~ 2008 Salem ~ Pod instruction manual
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yellowstonestu
Groupie Joined: 04 Mar 2013 Location: Colorado Online Status: Offline Posts: 43 |
Posted: 23 Feb 2014 at 6:41pm |
I had a hauntingly similar issue last summer with my 173. I had the thermostat replaced, it worked once, then same issue all over again. I took it to my local RV repair place, they couldn't find anything wrong, so finally took the inside cover off the ac unit and found two a loose wire nut there that came from the thermostat. Problem solved?? It worked when I put it away for the cold Colorado winter. Will know more in April when I take it out of winter storage.
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Yellowstonestu & Bela the Vizsla
2008 Toyota FJ 2015 RPod 179 (Pod #2) |
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Goose
Senior Member Joined: 24 Sep 2010 Location: Arizona Online Status: Offline Posts: 672 |
Posted: 22 Feb 2014 at 11:51pm |
Sounds like a lot of work, glad that you were able to make the repairs and get the furnace to work as intended. Goose
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Mother Goose's Caboose..2011 RP171..07 Grand Cherokee
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Tars Tarkas
Senior Member Joined: 14 Jan 2013 Location: Near Nashville Online Status: Offline Posts: 1447 |
Posted: 22 Feb 2014 at 11:33pm |
The furnace is up and running again. It was a broken thermostat wire. I determined that there was no continuity in the red thermostat wire so I started at the furnace end and pulled a new pair of wires through with the old wire roughly to the thermostat.
This is where it gets kind of interesting. The thermostat wires from the furnace do not go to the thermostat. No, they go to the air conditioner. It's a red and white pair that goes from the furnace to the air conditioner, then a 6-wire thermostat cable goes from the air con to the thermostat. You can't check the continuity from the furnace to the thermostat. You can check it from the furnace to the air con and from the air con to the thermostat. The long run with the most bends is the one from the furnace to the air con, so that's what I checked first. For the most part, pulling the wire pair along the existing chase was fairly routine. The cable anchor straps, mostly where the wires turn, were the trouble spots. All of them were doable though, except the one above the ceiling and the lower portion of the air conditioner, where the wire goes from the air conditioner, above the ceiling, over a little then down between the shower stall and the wall outside the shower. I could sort of pull the wire down a little way, so that the end would move up out of the air conditioner, but it would not move at all if I tried to pull it up from the floor, over the ceiling and down into the air conditioner. That's why I pulled from the furnace to about the thermostat. I spliced the new wire to the old wire more or less behind the thermostat. I had to loosen the paneling on the wall with the thermostat to make any of this work. Actually, in hindsight, I guess I could have spliced under the shower if I'd known in advance where the break in the wire was. I did find the wire break. As of now I don't know where it was in the run of wire. I'll see if I can get a good idea when I do the rest of my cleanup tomorrow and put away my tools. It shouldn't be too hard to get a good idea by laying the old wire out along its old path. I was surprised that the thermostat was not directly connected to the furnace. There's bound to be a good reason, but I have no idea what it is. I think you could run a two-wire, dedicated thermostat to the furnace, and that would have been marginally easier, but then I would have had two thermostats (and would have been able to run the air con and the furnace at the same time). None of this overall task was particularly difficult but it would have been much more straight forward if Forest River provided some schematics and better manuals. After carefully reading the manual for the "air handler", I discovered the thing about the furnace wires going to the air conditioner, but I still had no clue whether they went to the inside portion of the air conditioner or the part up on the roof. I took the cover off the roof portion looking for wires that weren't there and I still have to get up there tomorrow to put the cover back on. Thankfully there is no rain in the forecast. TT |
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2010 176
FJ Cruiser |
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Boomertype
Senior Member Joined: 12 Jan 2014 Location: Seattle Online Status: Offline Posts: 108 |
Posted: 15 Feb 2014 at 9:21pm |
Maybe I missed it but did you use a multimeter to check continuty for all the connections to the heater?
I never leave home without one.
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techntrek
Admin Group - pHp Joined: 29 Jul 2009 Location: MD Online Status: Offline Posts: 9062 |
Posted: 15 Feb 2014 at 4:48pm |
Yup, if jumping those same 2 wires at the thermostat didn't work I agree it is a wiring issue. If you can't easily run new wires to the original thermostat you could mount a dedicated thermostat near the furnace. Just not too close or it will cycle on/off too often and leave the rest of the camper too cold.
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Doug ~ '10 171 (2009-2015) ~ 2008 Salem ~ Pod instruction manual
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Tars Tarkas
Senior Member Joined: 14 Jan 2013 Location: Near Nashville Online Status: Offline Posts: 1447 |
Posted: 15 Feb 2014 at 2:16pm |
The furnace itself works! I was able to jump across the relevant connections at the furnace. With the top off of the bench above the furnace it is easy to see where the red and white thermostat wires connect to two light blue wires, one of which has a tape label marked ++++++. This is outside the furnace but under the seat box. The +++++ wire is indeed hot. When I connected those two light blue wires the furnace fan started instantly and the gas lit up in just a few seconds. Disconnecting that jumper caused the flame to go out. The fan ran for about a minute and quit, just as it should.
So, early advice/speculation was right on target. I'm totally satisfied now that the problem is in the thermostat or the wires between the thermostat and the furnace, and not with the furnace itself. I'm a little bothered still about the fact that nothing I could short across at the thermostat caused the furnace to start, so I don't know how the wires would have been damaged, but this seems to point to a wiring issue. They are skinny little wires and with the vibrations of normal travel something could have happened. I should be able to check the wires easily enough with an ohm meter though. I'll follow up and let you know how this finally resolves itself, but thanks for the help so far! I know what to do now.... TT |
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2010 176
FJ Cruiser |
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