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Topic: Funny, it worked before I fixed it... (Read 896 times) previous topic - next topic

Funny, it worked before I fixed it...

I re-installed my furnace with it's new motor finally.  I don't seem to have any power to it now.  My recollection is the motor should start up as soon as the thermostat calls for heat.  Hooking the motor up direct to a separate battery works, so its not a bad motor.  I have no schematic so my question for now, where does the main power supply come from?  I assume it feeds into the reset switch, but I'm getting nothing there.  (This is a single furnace setup, atwood 40,000 btu.)
1996 U270
Build #4846

Re: Funny, it worked before I fixed it...

Reply #1 –
Gayland,

Go to Heating Systems - Atwood Mobile

Click on and download the manual for your furnace.

Brett
Brett Wolfe
EX: 1993 U240
Moderator, ForeForum 2001-
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Chairman FMCA Technical Advisory Committee 2011-2020

Re: Funny, it worked before I fixed it...

Reply #2 –
Quote from: Gayland Baasch –
I re-installed my furnace with it's new motor finally.  I don't seem to have any power to it now.  My recollection is the motor should start up as soon as the thermostat calls for heat.  Hooking the motor up direct to a separate battery works, so its not a bad motor.  I have no schematic so my question for now, where does the main power supply come from?  I assume it feeds into the reset switch, but I'm getting nothing there.  (This is a single furnace setup, atwood 40,000 btu.)
Gayland,
I haven't looked at schematics recently, but my furnace (Atwood 40,000 btu)  has a significant delay in starting, after the thermostat is set to call for heat.  The delay is about 30  seconds.  I always assumed that the delay was to allow for the "shopping" (at the thermostat)  to die down before the furnace fan and then the ignition sequence is called into duty.  The "Fan Only" and AC's have a shorter (about 5 sec.) delay.  As I recall, 12Vdc is always available at a motor mounted relay, and the thermostat simply energizes the relay (or forward biases a transistor) to enable power to the motor.  There is a motor mounted "ON/OFF" switch, on the upper left side of the motor,  for that 12Vdc power to the relay that is sometimes balky.  Corrosion X generally makes it reliable again.
FWIW
Neal
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Neal (& Brenda) Pillsbury
'02 U320 SPEC, 4200, DGFE, Build #5984
'04 Gold Wing
'07 Featherlite 24'
'14 Jeep Grand Cherokee Summit
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Exeter, NH & LaBelle FL
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Re: Funny, it worked before I fixed it...

Reply #3 –
Okay, that all helps, I was able to jumper from the hot wire of the fridge to the furnace and the motor ran as it should, thus confirming my belief that its a power-in problem.  (Can't confirm heat, I'm out of gas.)  I have all kinds of schematics, but none for the house side 12 volt system.  Where does that power come from in the first place?  Is it fused?  Are there safety systems connected to the power-in that could have it shut down?
1996 U270
Build #4846

Re: Funny, it worked before I fixed it...

Reply #4 –
There should be a 15 amp fuse in the panel mounted to the bed base.  I don't know of any other possible power interupter besides the entry door master switch.  There is also the individual circuit breaker inside the furnace - verify it didn't pop without you noticing.
John Fitzgerald
1991 U300 (SAI) Side Aisle Island Bed 40'
Detroit 6V92 with Allison Retarder
Meridian (Boise), Idaho

Re: Funny, it worked before I fixed it...

Reply #5 –
In the fuse panel at the end of the bed there are fuses and on mine the fuse has been replaced with a re-settable fuse/circuit breaker.
Push in on the button and it should re-set.
Regards,
JON TWORK KB8RSA
Full Time RVer (10+ Years) & Dedicated Boondocker
Retired, Unemployed, Homeless Transients
1996 Foretravel U270-36 w/24' Timberwolf Trailer
I firmly believe that tomorrow holds the possibility for new technologies, astounding discoveries, and a reprieve from my remaining obligations.
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Re: Funny, it worked before I fixed it...

Reply #6 –
Three times is a charm, I guess.  I'd already looked for that panel twice.  The trick is to close the other breaker box so it's not hid behind it and lift the skirt up higher cause it's right at the top of the bed frame.  Thanks, that solved the problem, fuse was blown.  Now to get some propane and see if it actually heats  :o
1996 U270
Build #4846