Lennox furnace-code for open limit switch


  #1  
Old 01-30-16, 04:50 PM
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Lennox furnace-code for open limit switch

Hi, I have a lennox g40uh-36a-070-02 and have the code for open limit switch.
I have checked primary, secondary, roll outs, and pressure switches for continuity and all are good.

What can I be missing, or doing wrong?
Thanks
 
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Old 01-30-16, 05:41 PM
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The limits will reset when they cool down, but the furnace will be locked out for an hour. Are you checking the limits right after the furnace shuts down?
 
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Old 01-30-16, 06:20 PM
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If you are getting a code for an open limit than you missed one. Like Carbide said they will reset when they cool off. That means you need to check when it happens. I connect my meter to the control board and watch the limit from that location to see if one is actually opening.
 
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Old 01-30-16, 08:00 PM
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And make sure your filter is clean and dampers are all open.
 
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Old 01-31-16, 08:18 AM
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I found a loose wire at 12 pin! Looks like I got it licked!
Thanks guys
 
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Old 01-31-16, 10:06 AM
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That is a very common problem. Glad you got it fixed.
 
 

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