Furnace keeps shutting down


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Old 02-02-24, 03:20 PM
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Furnace keeps shutting down

My York 95% efficient furnace keeps shutting down. I had a problem before in which the float in the condensate pump was stuck, water backed up into the furnace, and it shut down. I took it apart and cleaned the pump, tested it, and it works fine.

The setpoint has been at 75 for hours as a test but the heat it's not running and it's 68.

Yesterday I wired the pump's safety switch to the logic board on the furnace in series and it worked great. It did intermittently today, too. But now it's off.

The pump is over 10 years old. Can a safety switch kind-of work? I am about to take it out of the circuit.
 
  #2  
Old 02-02-24, 03:47 PM
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Yes.... the safety switch float can get hung up.

The safety switch is only to shut down the system in case of condensate overflow.
You can bypass the safety switch to diagnose a problem.
 
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Old 02-02-24, 04:38 PM
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Update: I was getting 6 flashes, which is the same as 3 twice: "Intake, vent, or termination problem."
I removed the condensate safety switch from the wiring and it was working, but one LED slow flash: "Flame present with gas off."
It's odd that the codes on the door are different from the ones that are online for the TM8 series, but I will use the on the door.
I will monitor it tonight.
 

Last edited by DenverGuy; 02-02-24 at 06:11 PM.
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Old 02-02-24, 09:31 PM
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The condensate pump shouldn't generate any faults.
It should just stop operation by opening power.

I can pull up the manual if you post the full model number off the ID tag inside near the burner on the side wall.
 
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Old 02-03-24, 06:19 AM
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Thanks. I have the manual. It's a TM9EO80B12MP12B. I'm going to try to find a dealer. I hate York.
 
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Old 02-05-24, 06:37 AM
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Problem solved. First, it was an amber flashing LED - not red. My error.
Second, it turns out that it was a fault with the condensate pump. Apparently a switch wasn't working right. Also, the fill tube from the furnace was too long and extended right to the bottom of the pump reservoir.
I replaced the pump, shortened the tube, and it's all working - for now.
Thanks.
 
 

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