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Kenmartin1's avatar
Kenmartin1
Explorer
Jan 20, 2015

Atwood furnace troubleshooting help

I have a 1996 rv with two atwood furnaces and two roof ac. Everything worked fine until the rear furnace model 8520 stopped blowing heat, only the fan would run. I thought it was the sail switch, but with a test light, I found power going through the sail switch. It seemed that power was not going through the high limit switch, so I removed it, hooked it up to a car battery and a test light and it had continuity from the blue wire terminal to the yellow. My limit switch also has two red wires... Don't know what they do... Anyway, I put it all back together and now my thermostat skips the "furnace" mode for zone 2! It will only go from fan to cool to off!!!! I cant even send a call from the thermostat to start the rear furnace now! Anybody have any ideas? Thanks, ken
Class A
  • enblethen's avatar
    enblethen
    Nomad
    Jan 20, 2015
    Reset the thermostat.
    Many this is accomplished by removing fuse for 15-20 seconds, then let it reboot. This could take 20 minutes.
    If you have fluorescent light fixtures, a defective ballast can interfere with RF signal from some thermostats. Leave fluorescents off during reboot. After rebooting and system is working, turn on fluorescents and see if it fails.
  • Kenmartin1's avatar
    Kenmartin1
    Explorer
    Jan 20, 2015
    Ok, thanks. Thermostat reset worked, and...I found my main 12v feed wire to the rear furnace had broken by rubbing on the rear bumper bracket. After splicing the wire, and supporting it correctly, the rear furnace kicked on and runs like a champ!
  • crasster's avatar
    crasster
    Explorer II
    Jan 21, 2015
    Was the wire originally not supported well? If not, what was your fix? I've fixed several with simple zip ties.

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