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Old 07-03-2013, 10:42 PM   #1
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Central A/C not cooling


My Central A/C is acting up. We came home this evening and it was 85 in the house. The air coming out of the vents was hot. So I turned the unit off and checked all the easy stuff; filter, breakers, condensate line and those things were in order. I turned the thermostat back on after checking these things and the air coming out of the vents was cold, but only for a couple of minutes and then it warmed up. The condenser line on the outside unit is cold and the one on the inside unit is cold. What are my possible issues? Thanks in advance.

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Old 07-04-2013, 06:06 AM   #2
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Central A/C not cooling


feel that thin copper line going out of the condenser...should be warm but no hot in the morning.might warm up with the sun and temps rising.that insulated line should feel like a beer can pulled out of a cooler of ice...at the condenser and at the air handler.should have in general 18F split on the air handler(taken at the filter and just down from the air handler supply side)and out on that condenser 10F rise on air in and air blowing in your face...with the compressor running.NOTE just because the condenser fan is blowing doesn't mean the compressor is running when the stat calls it to cool.if the insulated line is chilled then the compressor has to be running...OK get back...short on Freon or might need too hose out the condenser from the inside out...tell me what that thin copper line feels like running along the insulated one just outside the condenser?

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Old 07-04-2013, 07:32 AM   #3
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Central A/C not cooling


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My Central A/C is acting up. We came home this evening and it was 85 in the house. The air coming out of the vents was hot. So I turned the unit off and checked all the easy stuff; filter, breakers, condensate line and those things were in order. I turned the thermostat back on after checking these things and the air coming out of the vents was cold, but only for a couple of minutes and then it warmed up. The condenser line on the outside unit is cold and the one on the inside unit is cold. What are my possible issues? Thanks in advance.
on the inside where the fan and relay's and wiring is their is a relay that click's for cool and heat, now maybe the relay has both heat element on and also the ac is on also , which would get you both ac and heat at the same time which would be warm, you need to have a ac guy come out and use a amp probe and put around the wire going to the element to see if it is drawing current at the same time as the ac unit is on ? If so change the relay, if it just started i doubt it is low on freon , it wouldn't cool than get warm, my 2 cent's good luck
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Old 07-04-2013, 07:45 AM   #4
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Central A/C not cooling


Sounds like the compressor is dropping out after a short run. When you turned it off then back on it reset and ran while you felt cold air. There are a number of things that can cause this. Thermal protection and pressure switches will turn off the compressor when their parameters are exceeded. You need to be standing by the outside unit when it is turned on and verify the fan is running well and the air flow is normal. You should also hear the compressor running separately from the fan. The compressor may start to get louder right before it shuts down. This indicates excess head pressure. If it dose not change sound then I would suspect an issue with supply voltage or the compressor windings.
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Old 07-04-2013, 08:10 AM   #5
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Sounds like the compressor is dropping out after a short run. When you turned it off then back on it reset and ran while you felt cold air. There are a number of things that can cause this. Thermal protection and pressure switches will turn off the compressor when their parameters are exceeded. You need to be standing by the outside unit when it is turned on and verify the fan is running well and the air flow is normal. You should also hear the compressor running separately from the fan. The compressor may start to get louder right before it shuts down. This indicates excess head pressure. If it dose not change sound then I would suspect an issue with supply voltage or the compressor windings.
What causes excess head pressure?
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Old 07-04-2013, 08:17 AM   #6
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Central A/C not cooling


Dirty condenser, condenser fan not working, clogged orifice or defective TXV to name a few.
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Old 07-04-2013, 08:53 AM   #7
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the heat of the compressed Freon out into the discharge either goes out with the fan in your face or takes a trip onto the Liquid Line.need OPr to touch that discharge line with the compressor running if he can touch it or even grab it...doubt it...be carefull......suppose to be super heated Freon .then the Freon is low and or the valves are worn not compressing need brand and model of that condenser...temp change on the in/out of the LL dryer will cause hi head and low suction....OPr any ice at the air handler?
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Old 07-04-2013, 09:02 AM   #8
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feel that thin copper line going out of the condenser...should be warm but no hot in the morning.might warm up with the sun and temps rising.that insulated line should feel like a beer can pulled out of a cooler of ice...at the condenser and at the air handler.should have in general 18F split on the air handler(taken at the filter and just down from the air handler supply side)and out on that condenser 10F rise on air in and air blowing in your face...with the compressor running.NOTE just because the condenser fan is blowing doesn't mean the compressor is running when the stat calls it to cool.if the insulated line is chilled then the compressor has to be running...OK get back...short on Freon or might need too hose out the condenser from the inside out...tell me what that thin copper line feels like running along the insulated one just outside the condenser?

The small line doesn't warm up or cool down, stays outside temp. The insulated line gets cold.

It doesn't sound to me like the compressor is ever kicking on, but it has to be right, since good cold air comes out for a minute or two? It never changed sounds, and it seemed like it kind of squealed when it kicked on before.
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Old 07-04-2013, 09:05 AM   #9
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the heat of the compressed Freon out into the discharge either goes out with the fan in your face or takes a trip onto the Liquid Line.need OPr to touch that discharge line with the compressor running if he can touch it or even grab it...doubt it...be carefull......suppose to be super heated Freon .then the Freon is low and or the valves are worn not compressing need brand and model of that condenser...temp change on the in/out of the LL dryer will cause hi head and low suction....OPr any ice at the air handler?

No ice, and I'm assuming the line I just touched is the discharge line and it was not hot. I touched it last night and it was not hot either. The bigger line is cold, but the other line just feels like it is outside temp.
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Old 07-04-2013, 10:23 AM   #10
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Central A/C not cooling


the raw copper line just out of the condenser is high pressure without the heat.as the Freon changes state to a liquid going to the air handler..if you want the discharge comes off the compressor and headers up onto the top of the condenser .they should be super hot to the touch with the compressor running..if like I said if you can touch it or grab it without getting burned you might be short on Freon...Note on that liquid to the air handler just compare it to you water nozzole as you spray your lawn...as the high pressure liquid goes into the COIL in the air handler it loses pressure as it sprays thru a TXV/orifice with the pressure drop the temperature drops on the freon and you get 40F to run house air over as it does..any chance for a split temp reading on that air handler even return grill and discharge register....
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Old 07-04-2013, 12:10 PM   #11
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Central A/C not cooling


The discharge line won't be hot after the condenser, just warm. It will brand you instantly on the other side. The suction line (bigger one) should be cold enough to sweat where it is exposed to humid air. The air flow should feel noticeably warmer than ambient.
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Old 07-04-2013, 12:15 PM   #12
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LIQUID LINE is outside the condenser DISCHARGE LINE is inside the condenser that is the one I need him to touch.if the condenser is matted with crap the heat will be trippin into the air handler on the LIQUID LINE....

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