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    Eyreflys's Avatar
    Eyreflys Posts: 4, Reputation: 1
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    #1

    Jun 13, 2008, 08:37 AM
    Trane XR80 Furnace Open High Limit Device
    I have a Trane XR80 furnace that has an LED flashing 4 times--Open High Limit Device. The filters are new and clean, I replaced the high limit switch, cleaned the flame sensor. Are there other switches I could check? Any other ideas?

    Thanks for any help or ideas.

    Brian
    hvac1000's Avatar
    hvac1000 Posts: 14,540, Reputation: 435
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    #2

    Jun 13, 2008, 10:06 AM
    Are you sure the high limit you replaced is a good one?

    Usually after you replace the limit and turn the power back on the code will clear.
    Eyreflys's Avatar
    Eyreflys Posts: 4, Reputation: 1
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    #3

    Jun 13, 2008, 11:34 AM
    Quote Originally Posted by hvac1000
    Are you sure the high limit you replaced is a good one?

    Usually after you replace the limit and turn the power back on the code will clear.

    Thanks for the quick reply. How would I test the new limit switch? Also is this the only switch that could be a problem?
    hvac1000's Avatar
    hvac1000 Posts: 14,540, Reputation: 435
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    #4

    Jun 13, 2008, 11:46 AM
    It depends upon the drawing but usually they are closed which means power will flow through it. When activated/defective it will be open and no power will flow through it.
    Eyreflys's Avatar
    Eyreflys Posts: 4, Reputation: 1
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    #5

    Jun 14, 2008, 10:36 AM
    Quote Originally Posted by hvac1000
    It depends upon the drawing but usually they are closed which means power will flow thru it. When activated/defective it will be open and no power will flow thru it.
    Well I tested the limit switch and the two manual reset flame rollout switches that are inline with the limit switch. All seem to work correctly. When I turn to power back on, the system will work for about 1 min, then quit with the open high limit device code. If I recycle the power it will again work for only a short amount of time... The only switch I can't get to is the reverse flow switch. I don't think that switch is the problem? I am starting to feel it may be the integrated furnace control? Any more ideas? Thanks again
    hvac1000's Avatar
    hvac1000 Posts: 14,540, Reputation: 435
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    #6

    Jun 14, 2008, 11:03 AM
    Quote Originally Posted by Eyreflys
    Well I tested the limit switch and the two manual reset flame rollout switches that are inline with the limit switch. All seem to work correctly. When I turn to power back on, the system will work for about 1 min, then quit with the open high limit device code. If I recycle the power it will again work for only a short amount of time... The only switch I can't get to is the reverse flow switch. I don't think that switch is the problem? I am starting to feel it may be the integrated furnace control?? Any more ideas? Thanks agian

    Your limit switch is a safety device for your furnace . It works by monitoring the operation of your furnace and if it's limit is exceeded then it opens or closes to tell the control board that it's limit has been exceeded . Most common limit problem is usually your "High Limit Switch" which monitors the temperature around your heat exchanger if it is exceeded usually more than 180 deg F it will open up causing a fault to show up on your control board . This does not mean that the limit is defective but rather that something else has caused the temperature limit to be exceeded ,most common being poor air flow through the furnace usually dirty air filter, blower or even a defective blower motor . Check and make sure you do not have any other problem that could be causing this situation.
    LlGgBb's Avatar
    LlGgBb Posts: 1, Reputation: 1
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    #7

    Nov 25, 2008, 07:32 AM
    Quote Originally Posted by hvac1000 View Post
    Your limit switch is a safety device for your furnace . It works by monitoring the operation of your furnace and if it's limit is exceeded then it opens or closes to tell the control board that it's limit has been exceeded . Most common limit problem is usually your "High Limit Switch" which monitors the temperature around your heat exchanger if it is exceeded usually more than 180 deg F it will open up causing a fault to show up on your control board . This does not mean that the limit is defective but rather that something else has caused the temperature limit to be exceeded ,most common being poor air flow through the furnace usually dirty air filter, blower or even a defective blower motor . Check and make sure you do not have any other problem that could be causing this situation.
    Your response to this question is very helpful. I've got the same diagnostic and your explanation makes sense.
    cinwnst's Avatar
    cinwnst Posts: 3, Reputation: 1
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    #8

    Dec 12, 2008, 10:37 PM
    I have a Trane furnace and am having problems with it the pilot light won't stay lite. The led will flash continuously then the pilot goes out, then turn it back on and flashes three times and goes out, turn it back on and then flashes four times. What's my problem? Without heat it is Friday night 9:36 p.m. how can I fix this problem in the morning?
    KC13's Avatar
    KC13 Posts: 2,556, Reputation: 99
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    #9

    Dec 12, 2008, 10:43 PM

    Find the service label with the LED diagnostic codes-usually on the control board housing or inside the blower/service access panel. Post results of your findings.
    cvmonk's Avatar
    cvmonk Posts: 3, Reputation: 1
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    #10

    Apr 1, 2009, 09:24 AM
    Did you ever figure out what the problem was? I am having the same problem and the limit switches are OK?
    morningla's Avatar
    morningla Posts: 2, Reputation: 1
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    #11

    May 15, 2009, 10:22 AM
    Hi, same issue here Trane XR80 4 flashing light.

    My thermostat signals the system and the motor starts blowing air, then the light starts doing the 4 flashes while to fan blows non-stop, not realizing that the burner hasn't ignited.

    The gas lines are turned on and other applicances working.

    Just stopped all of a suddent one day as I was only getting cold air.

    I've try powering down the furance and the same thing happens when I turn it back on.

    What can I do? I don't see the limit switch, all I see is the circuit board while looks fine.
    morningla's Avatar
    morningla Posts: 2, Reputation: 1
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    #12

    Jun 17, 2009, 07:22 AM
    So the limit switch was the issue.
    The tech came in and fixed this for me.

    All you have to do is follow your circuit chart to find the limit switch, mine was screwed in flush to the metal vents.

    Take that out, check power reading first (if you suspect it's dead), otherwise, smack it around a few times and it should reset.

    My issue was due to dirty filters.

    Screw it back in place and you're burner should fire up now.
    kagmachine1's Avatar
    kagmachine1 Posts: 6, Reputation: 1
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    #13

    Apr 10, 2010, 01:47 PM

    Where do I find the high limit device?
    MUSTANG67's Avatar
    MUSTANG67 Posts: 4, Reputation: 1
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    #14

    Nov 21, 2010, 06:46 PM
    Comment on cvmonk's post
    Did you ever figure out what the problem was? I am having the same problem and the limit switches are OK?
    MUSTANG67's Avatar
    MUSTANG67 Posts: 4, Reputation: 1
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    #15

    Nov 21, 2010, 06:47 PM
    Comment on Eyreflys's post
    Did you ever figure out what the problem was? I am having the same problem and the limit switches are OK?
    [RTFM]'s Avatar
    [RTFM] Posts: 1, Reputation: 1
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    #16

    Jan 15, 2011, 12:59 AM
    I have the same code so what I did is turn off the thermostat an just tried running the fan by its self an it wouldn't turn on so I think
    It's the blower motor.
    james0007's Avatar
    james0007 Posts: 1, Reputation: 1
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    #17

    Nov 10, 2011, 10:42 PM
    I have a Trane XR80 which got 4 flashes. I looked at the circuit board where the led flashes, used a screw driver to hit each corner once (not too hard). Now it works fine.

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