Do I need to replace the 624591-B crkt brd?


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Old 12-10-11, 02:25 PM
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Do I need to replace the 624591-B crkt brd?

I keep getting a "pressure switch stuck shut" signal on the board. I replaced the pressure switch and made sure the tubing was free of obstruction. I also replaced the rubber tubing to the switch. After being off for several days it worked ok for a few hours then started the three blinks again. The starter coil heats up ok. Any Ideas?
 
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Old 12-10-11, 05:33 PM
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When a pressure switch isn't closing, the problem is a bad pressure switch about 2% of the time. 98% of the time, the pressure switch is failing to close for a reason, usually because some part of the furnace heat exchanger, venting system or drainage system is plugged up to some degree and impairing the free flow of air and/or water (in condensing furnaces) through the furnace.

Identifying what is causing the problem can be difficult.
 
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Old 12-10-11, 05:43 PM
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You need to verify if the switch is actually closed or not. IF it is, as S/P said, finding the cause can be difficult but with the correct tools, know how, & persistence it can be done.
On the other hand, if the switch is not closed yet the board says it is, the board is likely the culprit.
 
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Old 12-11-11, 05:10 AM
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I have tested the pressure switch and it is open when the system is off and shuts when the inducer motor starts. Last night it worked ok for about three cycles then started the three blinks again.
 
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Old 12-11-11, 06:20 AM
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Replace the circuit board.
 
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Old 12-11-11, 06:48 AM
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Agreed. The circuit board is the culprit.
 
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Old 12-11-11, 07:59 AM
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I would not replace the board yet, you need to test to see if it is closed when the unit is acting up. With out verifying that the switch is actually closed while it is acting up and producing a 3 flash then you are just throwing parts at it.

I'm thinking there is a venting issue or heat exchanger problem and the problem is showing up after things get warmed up. I very well could be wrong, but without properly testing for the fault when the problem occurs you will never know other than throwing parts at it.
 
 

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