Author Topic: Central AC not cooling  (Read 414 times)

anonymouscow

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Central AC not cooling
« on: June 12, 2019, 01:00:38 PM »
Hello, I am trying to troubleshoot my central AC not cooling.

It will turn on and the air feels cool initially, but then it just feels like it's blowing at the air temperature.

Replaced the air filter, the intakes and vents inside are clear, the outside coils are clean, I looked up online how to test the capacitor and it tested good.

There were some bugs behind a control board (031-09104-000) which comes up as heat pump defrost circuit board, where the bugs were the pcb board around the resistors looks brown, the ac unit is older so I am debating ordering another board or just having someone come put to look at it.

Thank you for any help!

LifeHappens

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Re: Central AC not cooling
« Reply #1 on: June 12, 2019, 01:03:44 PM »
You might be out of coolant.

Wrenchturner

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Re: Central AC not cooling
« Reply #2 on: June 12, 2019, 03:11:04 PM »
You might be out of coolant.
This, or it could be your circuit board signalling ice up and cycling the compressor.  I would put an amp clamp on one of the compressor leads to see if it's cycling, and to see if it's under drawing amps ( indicating a coolant loss)

Wrenchturner

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Re: Central AC not cooling
« Reply #3 on: June 12, 2019, 03:13:13 PM »
Also it could be the reversing valves having issues.

Although if you have a brief output of cooling it usually indicates refrigerant loss.

Xlar

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Re: Central AC not cooling
« Reply #4 on: June 12, 2019, 04:46:34 PM »
Also it could be the reversing valves having issues.

Although if you have a brief output of cooling it usually indicates refrigerant loss.

I third the "out of coolant" (refrigerant) vote! My AC looses the refrigerant over the course of the year and the symptom that you describe is exactly the same as what I experience. And yes, I'm renting and my landlord keeps refilling it rather than fixing the problem...

Wrenchturner

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Re: Central AC not cooling
« Reply #5 on: June 12, 2019, 04:53:22 PM »
Also it could be the reversing valves having issues.

Although if you have a brief output of cooling it usually indicates refrigerant loss.

I third the "out of coolant" (refrigerant) vote! My AC looses the refrigerant over the course of the year and the symptom that you describe is exactly the same as what I experience. And yes, I'm renting and my landlord keeps refilling it rather than fixing the problem...
Not my kind of landlord...  at least modern refrigerants are eco friendly.

FIREstache

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Re: Central AC not cooling
« Reply #6 on: June 12, 2019, 09:14:51 PM »

Check to see if your compressor is running and that it keeps running.

mies

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Re: Central AC not cooling
« Reply #7 on: June 13, 2019, 04:48:48 AM »
It sounds like you might have a bad TXV (thermal expansion valve) or are low on refrigerant. I had a similar issue several years ago. If the refrigerant level is correct and you AC has a TXV, thereís a good chance itís the TXV.

big_owl

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Re: Central AC not cooling
« Reply #8 on: June 14, 2019, 08:25:32 AM »
Get one of those handheld IR laser thermometer guns (useful for a million reasons around the house) and then measure the temp of the refrigerant line before and after the JT (expansion) valve.  If after the JT valve the temp of the refrigerant isn't very cool (say, in the 60F+ range) then you're probably low on refrigerant (assuming your compressor is running).  Our units are typically in the 45-50F range immediately after the JT valve. 


Car Jack

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Re: Central AC not cooling
« Reply #9 on: June 18, 2019, 07:06:27 AM »
Call an HVAC company.  You (and the posters here) have no idea what's wrong.

Cadman

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Re: Central AC not cooling
« Reply #10 on: June 18, 2019, 07:22:33 AM »
I see a lot of shooting in the dark here. If this is a heat pump, step one is to see if it still functions in heating mode (with resistive elements off). If it works in heating but not cooling, then look at the reversing valve. Could be mechanical (stuck). Could be electrical (wiring, control issue, etc).

I'm assuming this is air-to-air and not geothermal?