Central A/C not cooling but freon pressure is OK


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Old 09-23-07, 12:22 AM
O
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Central A/C not cooling but freon pressure is OK

I have a 14 year old central A/C with Lennox model H25-311-P1 compressor.

This quit few days ago. Interestingly, it quit soon after an A/C Technician visited for regular servicing and checked the Freon pressure. The pressure was OK ( I remember around 80 psi ) when he checked with his gage.

Now the unit does not cool at all. Compressor fan is not blowing warm air to the outside. The 2 pipes that enter the evaporator in the attic are not cold either.

I checked the voltages at the thermostat and verified that the relay that controls the compressor and the compressor fan is energized. This is also evidenced by the fact that the fan turns. Lennox wiring diagram shows that the compressor fan and the compressor are wired in parallel so I assume that if the compressor fan is turning, the compressor must be getting power, too.

As a side note, when turning the unit on and off from the thermostat, sometimes the compressor fan remains stuck on. In other words, the thermostat is totally off and it has de-energized the relay that controls the compressor and the compressor fan but the fan is running for hours. It never turns off.

Any advice will be appreciated.

Oguz
 
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Old 09-23-07, 07:57 AM
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It sounds like your compressor isn't running. Open up the condenser and check your contactor and capacitor.
 
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Old 09-23-07, 08:04 AM
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On an R-22 system, I can't think of any reading of 80 PSI that would be OK. A relay that sticks on, probably needs to be replaced. It's also possible, that when he checked pressures, a schrader valve developed a leak and is no longer OK.
 
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Old 09-23-07, 08:39 AM
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Wink

Best bet is call that tech back now. Or might get a better tech. You have a lot of IF's IF's here
 
 

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