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bbaker2001's avatar
bbaker2001
Explorer
Dec 06, 2015

furnance turned off

2001 cardinal
furnace has been working great.
went out today and turned on. I flipped switch to high fan speed and I heard no difference. in 2 min furnace turned off. I noticed not much air was coming from vents.

I waited for about 15" and went out and turned on, fired up, but did not seem to get real warm before shutting down again. I can get the fan to turn on, but not much air flow.
  • bbaker2001's avatar
    bbaker2001
    Explorer
    Dec 07, 2015
    went out and turned on. it fired up and worked ok. it finally went off, but only when reached a temp well above what it should have been. did some checking, and I do think it is thermostat. I have seen post somewhere about changing it out. will try it.
  • Old-Biscuit's avatar
    Old-Biscuit
    Explorer III
    Dec 06, 2015
    Fulltimer50 wrote:
    Old-Biscuit wrote:
    Thermostat FAN does NOT control furnace fan. That is for the A/C Unit fan

    Furnace fan is controlled by furnace via t-stat

    Place t-stat fan control in AUTO
    Set t-stat to HEAT


    ??Turn temp setting down below current air temp??


    Furnace fan should start and run for up to 90 sec for 'purge'
    Then ignitor/main gas get voltage
    Main flame lights off
    And air from floor registers starts getting warm
    Rig warms up to set point
    Main flame shut down
    Fan runs for cool down cycle (cools off heat exchanger) then shuts down

    So does furnace fan come on when you hear 'click' at t-stat when you set it for heat?
    No fan first..no furnace
    Then you need to check t-stat, DC fuse to furnace fan motor, fan motor local on/off switch etc.



    :S :S

    IF you stand on your head :H

    :B



    Hey OP.......
    Don't hear 'click' at t-stat you when call for heat then t-stat is suspect.

    Which t-stat?
  • oldtrojan66's avatar
    oldtrojan66
    Explorer
    Dec 06, 2015
    I have seen this symptom when I forgot to turn gas on, or the tank was empty.
  • oldtrojan66's avatar
    oldtrojan66
    Explorer
    Dec 06, 2015
    I have seen this symptom when I forgot to turn gas on, or the tank was empty.
  • bbaker2001's avatar
    bbaker2001
    Explorer
    Dec 06, 2015
    thanks everyone
    yes it is in auto
    no I don't really hear a click when I move the thermostat up. I opened it uo to see if I could jumper it, but to many wires.
    I am sort of thinking of putting one of the portable units on.
  • ksg5000's avatar
    ksg5000
    Explorer
    Dec 06, 2015
    In my rig if I switched the thermostat from auto to high fan it would effectively turn off the heater - the heater fan would run for a while in the std cool down mode and then shut off. If you leave your heater on auto does it work OK?
  • Fulltimer50's avatar
    Fulltimer50
    Explorer
    Dec 06, 2015
    Old-Biscuit wrote:
    Thermostat FAN does NOT control furnace fan. That is for the A/C Unit fan

    Furnace fan is controlled by furnace via t-stat

    Place t-stat fan control in AUTO
    Set t-stat to HEAT


    ??Turn temp setting down below current air temp??


    Furnace fan should start and run for up to 90 sec for 'purge'
    Then ignitor/main gas get voltage
    Main flame lights off
    And air from floor registers starts getting warm
    Rig warms up to set point
    Main flame shut down
    Fan runs for cool down cycle (cools off heat exchanger) then shuts down

    So does furnace fan come on when you hear 'click' at t-stat when you set it for heat?
    No fan first..no furnace
    Then you need to check t-stat, DC fuse to furnace fan motor, fan motor local on/off switch etc.
  • Joe417's avatar
    Joe417
    Explorer
    Dec 06, 2015
    Your obviously getting enough air flow to close the sail switch if it fires up.

    I would start by removing the flexible supply duct and checking the air flow, checking that there was no restrictions.(lot of air will come out if disconnected)

    You said you heard no difference between high and low fan speed, your fan motor shaft lube may be getting dry causing the motor to slow, this happened on my AC last year. I kept running it (about 3 days) until it finally locked up.

    Either of these could cause the unit to cut off from an internal over-temp thermostat.

    If it had adequate air flow, fired up but didn't put out much heat, I'd look at restrictions in the burner.(Dirt daubers, mice)

    Good luck.
  • Old-Biscuit's avatar
    Old-Biscuit
    Explorer III
    Dec 06, 2015
    Thermostat FAN does NOT control furnace fan. That is for the A/C Unit fan

    Furnace fan is controlled by furnace via t-stat

    Place t-stat fan control in AUTO
    Set t-stat to HEAT
    Turn temp setting down below current air temp

    Furnace fan should start and run for up to 90 sec for 'purge'
    Then ignitor/main gas get voltage
    Main flame lights off
    And air from floor registers starts getting warm
    Rig warms up to set point
    Main flame shut down
    Fan runs for cool down cycle (cools off heat exchanger) then shuts down

    So does furnace fan come on when you hear 'click' at t-stat when you set it for heat?
    No fan first..no furnace
    Then you need to check t-stat, DC fuse to furnace fan motor, fan motor local on/off switch etc.

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