Forum Discussion

VA-Apraisr's avatar
VA-Apraisr
Explorer II
Nov 01, 2019

Furnace works; then doesn't; works again?

2003 Fourwinds E450. Last trip to NY, furnace did fine all day but went to bed and wouldn't hold temperature and could hear blow turn on but ignitor won't fire, so turned it off. Just got it back from RV repair and they said they replaced the circuit board. Checked it before I left and turned on, but as soon as I get home, won't turn on. Kept running thermostat up and down but nothing. Using a digital Honeywell thermostat btw and it's almost new. Can hear the "click" each time I turn off/on so think that's ok. So, turned it off and back on and it fired up again. Got up to 70 degrees, it turned off, and won't come back on to keep temp at 70. I've tried it hooked to house power, batteries and generator....makes no difference. House batteries are at 12.9amp so shouldn't be an issue. Before I lug it back 40 miles to shop, any ideas from the "thinking men" on the board?
Class C
  • bobndot's avatar
    bobndot
    Explorer II
    Nov 02, 2019
    VA-Apraisr wrote:
    I've tried it hooked to house power, batteries and generator....makes no difference. House batteries are at 12.9amp so shouldn't be an issue.


    The op said his batts are 12.9 volts not amps I assume and it makes no difference. Why would you think its a low battery ?

    I think the answer is in that link I provided. However, it might be easier to drive the 40 miles and go back to that dealer.
  • Yeti_plus's avatar
    Yeti_plus
    Explorer
    Nov 01, 2019
    I am in the check the battery camp, but not the 12 volt battery,. Check the battery in the digital t-stat. Even though you say it is a new stat the cheap batteries they sell with anything these days don't last long. And it is a lot easier to check t-stat battery than trailer battery.
  • ksg5000's avatar
    ksg5000
    Explorer
    Nov 01, 2019
    If your not plugged into shore power then what your experiencing sounds like your battery is getting low. Your heater only generates heat when the fan is running fast enough to open the sail switch (safety mechanism which much be open for the gas to flow) - and when your battery starts to run down the fan may energize but not run fast enough to open the sail switch. Just my 02.
  • bobndot's avatar
    bobndot
    Explorer II
    Nov 01, 2019
    I think the board was a bad board, it happens often enough to think that.
    If the tech thought that was the problem in the first place and he changed it, then it worked when you tried it, then stopped. I would think the new board is a bad board.
    I bought a Dinosaur board for my last rv and was told they make a more reliable board. It might sound silly, but I carry a spare.
    It's so easy to plug in a new board and most of the time it solves the problems with furnaces. At least doing that tells me if it in fact is a bad board or not, quick and easy.

    The only other thing that comes to mind is the your new wall thermostat. I remember people having issues using the auto mode on digital thermostats where it caused malfunctions between the furnace and fan, igniter, and A/C. You would have to google that cause I don't remember the exact problems with that and I cant find my saved info on it.

    read Old-biscuit and there is a link for more info within this thread

    https://www.rv.net/forum/index.cfm/fuseaction/thread/tid/28593590/print/true.cfm

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