A/C blows warm air, all fans running


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Old 06-24-12, 08:10 PM
J
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A/C blows warm air, all fans running

My AC started making a funny noise on Friday night so I went out to investigate and shifted the unit on the pad a little and the noise stopped. I came inside and the breaker was buzzing so I switched it off. Saturday morning I replaced the breaker and went to check the unit and it took about 30-45 seconds after we turned on the AC from the thermostat for the fan to kick on. I then noticed the air coming out was not cold and it only sounded like the fan was running, not the compressor. I have since cleaned the coils, hooked up a shop vac to the drain lines, and pulled the panel to check the capacitor and contactor. I noticed the neutral wire on input side of the contactor was looking melted and corroded and the terminals are rusty. When I pushed in the plunger on the contactor it started arcing and then worked fine. I do not have a multimeter with a MFD setting so I am unable to verify the capacitor but it does not have the typical appearance associated with a blown cap. This unit takes a double cap and I was curious if the cap could be bad or going bad and yet still run the fan? I have been told that if it was leaking refrigerant that the coils would be iced over and I am not seeing that, but was not sure if that source could be considered reliable, so I am not ruling out the possibility of low freon. Any suggestions????
 
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Old 06-24-12, 08:21 PM
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Low charge may take a while of run time before you notice it icing up. You need to determine if the compressor is running. Yes a dual-run capacitor can fail on one side and the other be ok. IE the fan could be running, but the compressor not run due to a failed capacitor.
 
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Old 06-24-12, 09:34 PM
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I don't believe the compressor is running after disconnecting the fan and trying the contactor. Good to know the cap could still be the issue I will try that first as it is inexpensive. The unit ran overnight last night and no ice on the coils. I am only familiar with 12V caps, so I am not sure if this helps, but it sounds like there is a lot of liquid inside. The past 36 hours has been a crash course in basic HVAC maintenance. Thanks for the help, I will reply after replacing the cap.
 
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Old 06-25-12, 06:11 AM
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Thanks, it was the cap. I took it in to be sure I was getting the same type and they tested it in the shop. Fan side read 5 and compressor side 0.
 
 

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