No electricity to the furnace, 69 Sovereign

[bilby05]

I have been looking through the stacks and stacks of threads on furnaces and haven't found the information I am looking for.

First time I cranked up the furnace it worked, but upon wiggling the wires it would stutter and click. I renewed the connections, where wires from the furnace unit hook into the main wires from inside the wall. I carefully marked all the wires so it's not likely that I crosswired anything.

Troubleshooting has not produced any conclusive info. I have current, from shore power, to all of the trailer lights and appliances except the ceiling light in the kitchen, the stove vent fan and the furnace. Seems like that would be a blown fuse? I have checked breakers, in the overhead next to the control center, and in the bathroom. All ok. I checked for blown fuses in the rear bay. They all seem ok. It has electricity to both sides of each fuse. I use a twelve volt test lamp. It lights up. At the thermostat there is not electricity. Checked it with a multi-tester. At the furnace there is no power to any of the wires. I checked them wire to wire and wire to ground. No light at the test light.

Are there any other fuses around anywhere? If there is electricity to the car-like fuses in the rear panel shouldn't that be where the furnace connection is? Also the pilot light lights(and stays lit) and the little sparking gadget to light it also sparks. The AS came without a battery installed, the battery terminal connections are wrapped with what appears to be rubber inner tubing and tape. Tommorow I phone Helen Davis to order a service manual.

Any help would be greatly appreciated.

[Jim & Susan]

Originally Posted by bilby05

Tommorow I phone Helen Davis to order a service manual.

That was going to be my first suggetsion, call Helen. If you have no power at the furnace, you've only got a couple of options. Blown fuse or bad wire someplace. Also, don't overestimate the power of a P.O. Anything could have been changed down through the years.

Jim

[bilby05]

...don't overestimate the power of a P.O. Anything could have been changed down through the years....
Jim[/quote]
>>>>>>>>>>>>>>>>>>>>
When I was rebuilding an Austin Healy Sprite we referred to the previous owner as the "DPO" as in Darned Previous Owner, or something like that. they could do the darndest things. Same thing with Vespas by the way. I bet its that way with a lot of things.
cheers,

[nickcrowhurst]

Bill, it's always difficult to troubleshoot at a distance, but I am curious as to your statement that "At the thermostat there is not electricity." The thermostat is only a switch, so there will be no measurable voltage between the input and output terminals of the thermostat. You need to measure between the input terminal and ground (frame, bare of paint) to see if there is voltage (12.5 v approx) at the thermostat. ( You've probably already done this.) I would disconnect the two (blue?) wires from the back of the thermostat, fix the bare ends together in a wire nut, and at least eliminate the thermostat as the source of the problem. If the stat is defective, the furnace power relay (if your model furnace is fitted with one) will not be switched, and there will be no voltage at the furnace. Just a thought. Good luck in your search.
Nick.

[igor]

Bill,
What you are describing is how my '72 is wired. One fuse controlls the center vent light, fan if it had one, the galley light, the galley fan and the furnace. I have manuals for mine, they help ALLOT. But, with the asumption yours is wired similar to mine they all should be the same source. The wires run on the curb side of the overhead vents, in essence down the middle of the coach, branching off to go to their respective ends. I do know the only fuse in mine is at the univolt, if memory serves it is fuse #2, in fact the only fuse anywhere under the sink is for the water pump. I am at work now, if you think it will help I will look at my schematic when I get home in the morning.

Also, I think the thermostat gets its power from the furnace thermorelay and then when the thermostat calls for heat it sends power back to another terminal on the same thermorelay.....I think.....running off of memory.....and it's 0240 in the morning.

Let me know if I can be of any help

Les Brush

[bilby05]

Originally Posted by igor

Bill,
What you are describing is how my '72 is wired. One fuse controlls the center vent light, fan if it had one, the galley light, the galley fan and the furnace. I have manuals for mine, they help ALLOT. But, with the asumption yours is wired similar to mine they all should be the same source. The wires run on the curb side of the overhead vents, in essence down the middle of the coach, branching off to go to their respective ends. I do know the only fuse in mine is at the univolt, if memory serves it is fuse #2, in fact the only fuse anywhere under the sink is for the water pump. I am at work now, if you think it will help I will look at my schematic when I get home in the morning.

Also, I think the thermostat gets its power from the furnace thermorelay and then when the thermostat calls for heat it sends power back to another terminal on the same thermorelay.....I think.....running off of memory.....and it's 0240 in the morning.

Let me know if I can be of any help

Les Brush

Igor,

Thanks for the info. The way mine is set up is; the only fuse block I can find(other than the main one behind the control center panel in the front overhead) is inside the rear hatch to the right of the battery box. It has 5 fuses, and each one is functional. I removed them and checked them by putting them between the hot side and test lamp and ground. Several listers have mentioned fuses at the "univolt." The univolt in mine is in the curbside bay and does not seem to have any fuses anywhere near it. I guess I am going to have to get a manual. I checked and they said they did not start publishing them until 1974 model year and run about $75. but that the 74 manual would be useful for the '69.

It seems like I could have two problems. Fuse for one. That would account for no power to furnace, center overhead light and stove vent fan. Although having checked them I cant see how it could be a fuse. The other could be the connection to the thermorelay. But that would not account for the fact that when I first hooked it up the furnace worked, but when wiggling the wires putting stuff back together the furnace stuttered and cut out. Still a big puzzle.
thanks again,

[igor]

Bill,
Going with the assumption the wires run similar to mine, I don't think it would be the thermorelay, because, power comes (on mine from the univolt, under the end cover there are fuses) up through the wall, forward in the roof of the trailer to the center vent & light (it has it's own ground), down the roof/wall to the sink light (it's own ground) & fan (it's own ground) then down the wall to the furnace (the furnace does not ground through it's chassis, it has a ground wire). So, my guess is you have to have a power interuption somewhere (upstream) of the roof vent. And being it worked, then did not, I am betting on a fuse - somewhere.

Of course the pain is, to do any work on the furnace you have to pull the burner out. Not as hard as it sounds.

Definately get ahold of Helen, I have a reprinted owners manual - basic operation of the trailer type stuff, and a maintenance manual - how to work on the thing for my '72. The maintenance manual has complete break down of all systems, trouble shooting guides, wiring schematics the whole meal deal. Highly recommended, I have to assume if she had the things for my '72 she might have them for your trailer. Good luck, holler if I can be of anymore assistance.

Hope this helps a little

Les Brush

[Jim & Susan]

Bill, does your Univolt look anything like this? Can you see the fuses? They're behind the door on the front of the unit.

[SafeHarbor]

Hi, Bill,

As a licensed aircraft mechanic who hasn't practiced in years, my first suggestion would be to set the thermostat low, wiggle the wires again, and see if it starts working or blows a fuse. If it does either, the next step would be to look inside the wall right around where the wires exit for chaffes, melts, joined wires, and shorts to ground.

Good luck.

Lamar

PS - And, no, I have not worked for any major airlines.

[bilby05]

Thanks for all the help. I tried a little bit of everything suggested, and will save the data for future use.

Once I hooked up the battery charger to the "big red wire and big white wire" on the furnace it ran. Once that isolated the problem as a definate wiring problem I was able to track down the connections.

I found the problem up front in the overhead panel behind the clock, etc. The connection at the low voltage terminal was a bit loose so when I would attach my test light to it the connection would be made and it would also produce a small spark. With that the furnace fan would cut on. (I twisted the old thermostat wires together to assure a contact before starting the search)No blown fuses anywhere, but just a loose nut.

The owners manual was some help, but I think I will probably order the service manual also.

I also installed a new Hunter thermostat. Might as well fix it up as I go.

The "univolt" is a weird machine. It looks somewhat like the ones in the pictures, but since I found the short before I had to open it up I can always hope that I will never have to. :-)

I got enough of a fright from the stories about CO poisoning to assure that I will pick up a CO monitor before we use the furnace for anything but testing.

Today I yanked out the yellow/gold/black carpet and will be replacing it with something that does not glow in the dark. Not much water damage. But enough to keep me watching for leaks from the front end.

Thanks again for all the help.

[igor]

Bill,
Glad you found the problem, I often have the loose nut problem but usually it is sightly aft of the steering wheel!

I don't know about removing the carpet, could have cut down on battery usage (glowing in the dark) while boondocking

Take care,
Les