Forum Discussion

toaobigal's avatar
toaobigal
Explorer
May 17, 2014

Blower on my furnace keeps running.

I have a Atwood 8500 IV series furnace, this morning I started the furnace and I have heat. However, when it's warm enough, the blower runs for a little while longer than eventually stops: that's the part where I have the problem. The blower keeps running, I waited 1 hour and it won't stop. I had to turn the power/breaker switch on the blower to off. I don't think it's the thermostat because the heat works. I'm wondering if someone else had a similar problem. I tried removing the fuse that feeds the furnace, as soon as I put it back the blower is running, even if the switch on the thermostat is in the off position ( Dometic thermostat, with A/C) The A/C works ok. For now we're using an electric heater...
  • Old-Biscuit's avatar
    Old-Biscuit
    Explorer III
    May 19, 2014
    That ON/Reset switch on furnace is a 'slow blow' circuit breaker/switch.
    It takes high/prolonged amp draw to trip them.

    Also used as a 'maintenance switch' when working on furnace.

    Time delay relay......you might be lucky and it's a stand alone relay vs being part of board.
  • toaobigal's avatar
    toaobigal
    Explorer
    May 19, 2014
    Sorry I couldn't post a reply, the wifi was down at the campground. Old Biscuit is right about the fan setting. There's a switch on the blower motor that says On/Reset, turned that off when my problem happened and the motor stopped. Turned it back on again this morning and it looks like it has resetted itself, So I believe the problem could be with the time delay relay. I'll check into it next week-end. Thanks for all the advices.
  • Old-Biscuit's avatar
    Old-Biscuit
    Explorer III
    May 18, 2014
    First off.......
    The 'fan' setting on t-stat is for the A/C Unit fan. Has nothing to do with the furnace fan. If t-stat fan setting is in ON position the A/C Fan will run when furnace is turned on. But it's the A/C Fan

    OK. Furnace problem----fan continues to run
    One of three possibilities
    1) Faulty t-stat
    2) Shorted furnace wires from t-stat
    3) Bad relay (Timed Delay Relay)

    The relay is on the circuit board......it controls the fan power
    When t-stat contacts make up 12V power goes to timed delay relay and allows power to fan motor.....after temp has been satisfied t-stat contacts open, main flame goes out and fan should continue to run until relay opens the circuit shutting down fan.
  • karthuntr's avatar
    karthuntr
    Explorer
    May 18, 2014
    My heater had the same problem. The relay on the board that turns the fan on was stuck. Its a closed relay but I was able to tap the relay with the back of a screw driver to unstick it and haven't had any problems since. If it continues you will have to replace the board.
  • scbwr's avatar
    scbwr
    Explorer II
    May 17, 2014
    Check to see if fan setting on thermostsat is set to auto. On my thermostat, if I leave it on auto, the fan will keep running...happened once when I went to test AC.

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