A/C Fan (outside unit ) not turning ON - please help to trouble shoot -

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Old 06-29-16, 01:17 PM
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A/C Fan (outside unit ) not turning ON - please help to trouble shoot -

I have a AC unit - Thermostat unit seems to be fine - when you take the temp below set point - outside contactor unit pulls in - makes a buzz noise and nothing happens
Just changed the capacitor - thinking the problem was the capacitor -
( It is a Goodman unit )
What do I check next - please help -
 
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Old 06-29-16, 01:24 PM
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Be sure and check the breaker for the AC unit.
 
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Old 06-29-16, 01:26 PM
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You said that the outside fan isn't running. Is the compressor turning on when the contactor pulls in?
 
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Old 06-29-16, 01:35 PM
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How do I check if the compressor is turning on - Don't think so -

Also, checked the breaker and it is not tripped.
Have a multimeter - will check the voltage and confirm -

Thanks for your help ...
 
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Old 06-29-16, 01:47 PM
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You should hear the compressor turn on (most are reasonably loud). Turn off the power to the outside unit (likely is an electrical disconnect located near the outside unit), and remove the cover to access the "guts" of the outside unit. Turn the power back on and locate the contactor (relay). You should see two large diameter wires on each end of the contactor. Set your multimeter to AC volts and measure across the pair of wires at each end. One end is the input (240VAC continuous), the other end is the 240VAC output (present when contactor is engaged by thermostat calling for cooling). Be very careful working around the unit with the power turned on, as 240VAC is lethal.
 
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Old 06-29-16, 02:14 PM
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Checked the Voltage after removing the cover at the - Input to Contactor is 232VAC , and then when thermostat calling for cooling - Contactor pushed in - 232VAC at the large diameter wires -
Compressor doesn't make any noise or sound - its very low humming sound coming.
Appreciate your help - is there any thing else I can check that would be helpful
 
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Old 06-29-16, 03:16 PM
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Does the unit use a dual capacitor (3 leads)? Often a capacitor is used for the compressor and one for the fan. If your unit has a dual capacitor, or 2 separate capacitors, both the compressor & condenser capacitors could be bad. The capacitors are relatively cheap (<$20), so it's probably worth trying before you resort to calling in a technician. If you have a dual cap, one side will be large (~40mfd), while the other side will be small (~5mfd). The large side is for the compressor, the small one for the fan.
 
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Old 06-30-16, 05:01 AM
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A/C Fan (outside unit ) not turning ON -

The CAP is 370VAC - 30/5 MFD - Already replaced and tried it - doesn't make any difference - same problem -
 
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Old 06-30-16, 05:12 AM
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It's odd that both the condenser fan AND compressor aren't coming on even though there is voltage coming out of the contactor. Turn off the power to the outside unit and remove the connector (usually 3 leads) that plugs into the power terminals on the compressor so that the 3 compressor power terminals are exposed. Take your ohmmeter and measure resistance between the different terminals. What do you get?
 
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Old 10-13-16, 09:44 PM
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Check for 240v at the breaker box first, there are two different circuits for the compressor/fan and another one for the control side of these. In other words even if the breaker for the outside unit is off the control side will stay energized and contactor will pull in when call for cool. Most of the times you can hear the ac compressor they are rather loud and the fan attempting to start if this is your situation try to stick someting like a long screwdriver between the vents on top and "help" the fan in the direction it rotates if it catches and continues to spin your cap is bad Assuming all connections n wires have been checked
Good luck!
 
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