AC Not Running

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  #1  
Old 07-02-18, 09:27 AM
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AC Not Running

My air conditioner stopped running yesterday.

I checked the furnace, and everything seems to be running well on that side, however the air that is coming from it is not cool, about the same temperature as a fan.

The air conditioner unit is not running. The compressor makes a noise like it's trying to start for a few seconds but that doesn't. There's a low noise that it makes for a while as well. The fan also doesn't run. When I moved it with a screw driver, it started running, but the compressor still doesn't run even after that.

I'm thinking maybe something with the capacitator or contactor, but don't have a voltmeter to do any more checking.
 
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Old 07-02-18, 10:06 AM
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Welcome to the forums.

Since the fan and compressor are active.... the contactor appears ok. You'd need to check into and replace the capacitor. Since you don't have a meter..... just replace the capacitor. Usually around $20. It can be found in the wiring compartment where the main power wiring connects.

Turn power off to the outside condenser before opening the wiring compartment. Using an insulated handle screwdriver..... short across the capacitor terminals to insure it's discharged. Take pictures of the wiring and note very carefully where the wires are connected on the cap.

You can post pictures here too.... How-to-insert-pictures
 
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Old 07-02-18, 10:07 AM
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From your description of the problem, it sounds very likely that the capacitor is bad. The fan running after being given a push start is a classic symptom of a bad capacitor. The contactor runs both the fan and the compressor so, since the fan is running, the contactor is likely not the problem. Many systems use a dual capacitor, where one side is used for the fan and the other for the compressor. If both capacitors are bad, that would explain why the compressor isn't starting. Capacitors are relatively cheap, so I would suggest you start by replacing it.
 
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Old 07-02-18, 11:14 AM
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Thanks guys! Here are some photos of capacitator and contactor, and a washed out image of the AC unit info.

What kind of capacitator should I look for. Does it need to match exactly the the existing one.
 
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Old 07-02-18, 11:25 AM
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Excellent picture.

See how the contact area on that capacitor is like a dome ? That cap has blown its cork and is bad. You need a dual capacitor..... 30/5 Uf @ 370v or 440v.

The contactor looks "ok" at this time but I'd either change it or get a spare to have on hand.
 
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Old 07-02-18, 02:34 PM
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I replaced the capacitor with a new one, but it wasn't able to start both the compressor and fan. I decided to call a pro to look at it, and he had to mount 2/3 capacitors in order to start both. He said there was low pressure in the refrigerant ~30 (don't know units psi?) and it was causing issues. The fan stopped running after a few minutes and the fan motor was also very hot, too hot to touch, and there were visible oil leaks from the fan motor onto the compressor housing. The hvac guy suggested I buy a fan motor to replace the old one, and refill some of the refrigerant to up the pressure. Any ideas?
 
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Old 07-02-18, 03:12 PM
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I don't understand what you mean when you said " he had to mount 2/3 capacitors in order to start both". It's possible that the fan motor needs replacing, however before doing that, I would let the motor cool down (leave unit off until it cools) and then see if it quickly gets hot after you turn the A/C back on. The bad capacitor could have caused the motor to overheat, that's why I suggest trying it again with the new capacitor.
 
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Old 07-03-18, 07:56 AM
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He used an additional capacitor, and then two, to finally get both compressor and fan starting. The fan only ran for a few minutes and got that hot. My neighbor (townhouse) that has the same unit which was running for much longer was much cooler in comparison. The power to the condenser unit was off before that, so there shouldn't have been another reason for it to overheat. Will try to test what you said anyway, but might go get a fan motor, and return it if I don't use it.
 
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