Batteries won't run Furnace

[6PackCharlie]

My furnace unit is a hydro-flame 8535 III.
My batteries are fully charged, but will not spin the blower fast enough to cause the furnace to light. There is a squeal when the furnace blower comes on. As soon as I plug into shore power, the furnace lights. The blower needs to either be lubed or replaced. Does anyone know if I can get to the blower without taking out the entire unit.
Any hints as to what needs to be removed to get the unit out will be greatly apprecitated.

Charles

[masseyfarm]

Good info on this here.
http://www.airforums.com/forums/f313...per-70157.html

Sounds like the bearings are going on the motor??? How old is it? The motor will need replacement if it is the bearings. Otherwise it is touching something.

Dave

Also, manual can be downloaded from the Atwood site. All 8500 III series are much the same, with series IV an improved version that fits the same hole.

[garry]

Not sure of the Hydro Flame model # but when mine started squealing I took it out put it on the bench and could not make it squeal reinstalled that was 2 years ago and have no problems since.

Since the bearings seemed to be good I assume something was rubbing but have no idea what.

Not a big deal to get out you can down load the manual but basically you shut off the gas, disconnect the gas line, remove a few wires to the control board, remove the outside input/exhaust and I think there were 2 screws into the floor at the front.

It also sounds like you need to check the cables at the battery if OK have the battery load tested.

[6PackCharlie]

Dave,
I assume the motor is the original that came in the Airstream. If that is the case, it is @ 15 years old. I will try and download a manual from Atwood.
Thanks
Charles

[Mainstream]

If your furnace has had a normal amount of use in that 15 years it almost certainly will need a new motor. Be prepared to spend about $130 to $150 or more just for the motor and unless you are very mechanical inclined don't attempt to replace it yourself. I have replaced many of them and it can be a bit tricky, from pulling the furnace to tearing it apart and replacing the motor. Also while you have it apart inspect the burner as they tend to deform and start breaking apart. Clean out all debris and mud dobber nests while you are at it. I have even found mouse nests and dead mice trapped in them. Not very healthy to have that stuff blowing through your vents.

[masseyfarm]

Originally Posted by 6PackCharlie

Dave,

Originally Posted by 6PackCharlie

I assume the motor is the original that came in the Airstream. If that is the case, it is @ 15 years old. I will try and download a manual from Atwood.
Thanks
Charles

I have sent you a PM. Check your mail.
Dve

[6PackCharlie]

I took the blower motor out of the furnace and lubed the bearings. Ran it on the bench and no squeak. Put the furnace back together and the batteries still won't run the furnace (no squeak). I can put my battery charger onto one of the batteries and the blower rpm's noticibly increase and the furnace lights. The same thing happens if I add a third battery (or plug into shore power). The batteries are fully charged, just won't spin the blower fast enough to get it to light.

[BigAl]

In that case sounds like the batteries. Try disconnecting the trailer batteries and using only the third battery. Should work off one battery. Not all trailers come with two batteries.
Al

[6PackCharlie]

According to my tester. The batteries are fully charged.

[Jammer]

Charles

There are are only three possible source of the problem:

1) batteries
2) blower motor
3) everything else

Get thee a voltmeter thou canst trust.

Measurest the voltage at thy battery whilst thy furnace is running.

Should the voltage measure below 12.7 volts, replacest thy batteries as the source of the problem is: 1) batteries.

Otherwise, measurest the voltage at thy furnace. Should the voltage measure above 12.0 volts, repleacest thy blower motor, for its bearings are faulty and it is serviced as an assembly.

Finally, should the voltage at thy batteries be above 12.7 volts and the voltage at thy furnace below 12.0 volts, despair is your lot, as thy 12 volt distribution wiring has contracted the vapors.

[6PackCharlie]

I will check those locations as soon as the wind chill get back above below zero. Thanks.

[Aage]

Another thing to verify is that there are no corroded connections between your batteries and the blower motor. This could be a dirty battery terminal, corroded switches, or corroded connectors in the wiring where wires connect to a switch or a terminal block.

Also, kinks in the wires as they pass through various areas / sections / wall panels might allow leaks to ground dropping final voltage.

Last thing that I can imagine that might happen is if the mounting of the heater casing or motor mounts is skewed or twisted somehow, excessive friction could impede the freedom of the fan.

Hey, it ran on the bench: what's the difference between your bench and in the TT? Answer: the power supply (you didn't use the trailer's power to bench test it, did you?) and the mounting.

Good luck and good hunting!

[TG Twinkie]

I agree with Aage. I think you have a voltage drop problem caused by lose or dirty corroded connections. If the motor does not have a separate ground wire then it must be grounded thru the frame of the furnace. Make sure there is a ground wire running from the frame of the furnace to the skin of the trailer.
When you connect the shore power cable, the battery charger and or converter will take the voltage to somewhere around 14 volts.
The battery voltage alone won't be that high, only around 12.5 that addtional 1.5 volts is probably why it works. The motors speed is directly proportional to the voltage. The higher the voltage the faster it will run.
What kind of tester are you using to test the batteries?
With the blower running check the voltage at the batteries (in the battery only mode) then go to the blower and test the voltage there.
Then turn the furnace off and check the voltage at both places.
Let us know what you find.

[mademoiselle]

I have a new FC 23. Batteries show a full charge. Without shore power when I turn on furnace I get an E7 error (not enough power?). Furnace works fine on shore power.

[PKI]

Furnace or heat pump? The furnace should run if no functional problem exists.
The heat pump will not run on battery power, but the fan should.

Sounds like the battery bank is not capable of running the furnace fan motor. That sounds like you may not be correctly measuring the battery state.

Battery state should be measured after shore power has been removed for 30 minutes to an hour. A 12.7 volt measurement is full charge. A 12.2 measurement is 50% charge. No less should be allowed on a wet cell bank. If you have not been correctly reading the state, the bank may be damaged and in need of replacement.

Turning off most power loads when measuring battery state helps. If the furnace is on, that load will lower the voltage reading. Lights and other loads have a similar impact.

With any luck, your troubleshooting/investigation will provide more data and one of our resident experts will have the specific answer.

Note there are 23 specific threads. This is a problem that is likely not 23 specific and therefore need not be addressed on those threads. The store switch is different on a new 23, so some of our historic direction on that issue may be out of date. However you should have warranty. Call your dealer or Jackson Center for help.

Good luck with resolving the problem. Pat

[OTRA15]

Originally Posted by mademoiselle

I have a new FC 23. Batteries show a full charge. Without shore power when I turn on furnace I get an E7 error (not enough power?). Furnace works fine on shore power.

Welcome to the forum!

FYI you have tagged onto a very old thread. Pat just made a number of good suggestions.

I would call your dealer ASAP, and let them guide you through the diagnosis of the problem. There are many possible reasons for your predicament.

Good luck!

Peter