Pressure Switch Stuck Closed


  #1  
Old 06-23-09, 12:47 PM
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Pressure Switch Stuck Closed

I have a coleman g8c07512mub12g HVAC system. I have recently had a control board replaced because of a lightning strike. The heat was working fine when the control board was replaced, but no one ever checked the A/C. I tried to turn on the A/C and the control board flashes twice (indicating pressure switch closed), and no fan or anything else turns on. The heat still works fine.

Would you think this is a bad pressure switch even though the same pressure switch works for the heat?

Please advice me on how to proceed.

Thanks
 
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Old 06-23-09, 05:28 PM
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There is no direct relationship between the pressure switch and the cooling. I think you have 2 problems.
 
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Old 06-24-09, 04:31 AM
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I'am not familiar with Coleman numbers, is this a heat pump?
 
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Old 07-12-09, 07:19 AM
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Originally Posted by daddyjohn
There is no direct relationship between the pressure switch and the cooling. I think you have 2 problems.
So you're saying that the pressure switch has nothing to do with the cooling system? Why is it that the heat works fine.

I dont think this is a heat pump system, it uses natural gas for heating and there is a condenser outside for cooling.

Here is a link to my system:
http://www.yorkupg.com/PDFFiles/035-...001-E-0805.pdf


What two problems do you think i could possibly be having? Any troubleshooting steps i can follow?
 
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Old 07-12-09, 12:42 PM
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You have a stuck closed pressure switch problem and a cooling problem = 2. Dont assume that whoever replaced the board knew what they were doing.

The pressure switch senses the presenece of combustion airn[proves the inducer fan is running]. Would you want the furnace to start if there were no combustion air? I wouldn't. If you're getting a reading that the pressure switch is stuck closed and the burners will still start up ok, something is wrong.
 
 

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