Fan Running, Condense continuous restart/short


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Old 12-29-14, 08:34 PM
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Fan Running, Condense continuous restart/short

I have change my cap once before so I have limited experience working under the hood of my central air condenser unit. I noticed my condenser was shutting off periodically and the problem got worse over time.

Now my fan will stay on, but as soon as trigger temp is set the condenser kicks on for a few seconds, shuts off, and starts again. Other than the restarts, everything sounds and looks normal. Seems like a possible short? I checked the connections and everything seems fine.

I'm thinking it is something simple but I can't find a specific scenario in any searches... I know it's winter for most but not quite here in south Florida Any input is appreciated.
 
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Old 12-29-14, 09:37 PM
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Welcome to the forums.

Your problem is not very clear. You changed the capacitor for the compressor? The cap normally causes the compressor not to start. Was your compressor shutting off or entire condensor... which is compressor and fan in the outside unit ?

What fan is staying on ?
The compressor should be running and then with the target hit it should shut off. Do you mean it's running and then shuts off and then starts again ?

Try to explain in a little more detail what is exactly happening.
 
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Old 12-30-14, 05:42 AM
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I doubt it's a short or you would be clearing a fuse,sounds like a loose connection,but does this happen consistently?
Geo
 
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Old 12-30-14, 05:43 AM
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Sorry I was unclear!

So far I have no changed anything, I was just noting that I'd done a simple repair in the past.

Currently, the handler blower fan will come on inside the house. When the target temp is hit, the condenser comes on outside as well. Issue is that very soon after the condenser turns on, it quickly turns off and then after a few seconds starts again.

So essentially when the target temp is hit, the condenser turns on but goes into a loop of restarting. Almost like it is shorting out (the time it takes to shut off at starting is 5-15 seconds).
 
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Old 12-30-14, 06:58 AM
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How long does this cycle of ON/OFF last?
Geo
 
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Old 12-30-14, 08:25 AM
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The start / restart interval is very short, 5-10 seconds. Really stumped here!
I am unloading a video now.
 
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Old 12-30-14, 09:28 AM
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here is the video of whats happening

https://drive.google.com/file/d/0B9r...ew?usp=sharing
 
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Old 12-30-14, 10:34 AM
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Can't view your video on my phone but it sounds like you are cycling on a pressure switch.
 
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Old 12-30-14, 10:35 AM
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It appears the top red wire going to the dual run capacitor has a burnt spot.
 
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Old 12-30-14, 12:41 PM
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That was my first thought,but is it normal for a residential unit to have a LP switch?
Geo
 
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Old 12-30-14, 06:52 PM
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The burnt red cable was already burnt when I replaced the cap last time so that is not the problem (I did cut and recap the red cable though just to be sure, and it isn't).

I've looked at everything and the connections look ok, any other ideas?
 
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Old 12-30-14, 07:42 PM
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Trace that yellow low voltage wire from the contactor to under the control box to see if it hits a pressure switch.

 
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Old 12-30-14, 07:54 PM
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Just checked and it sure does!Name:  IMG_20141230_224940.jpg
Views: 220
Size:  45.0 KB
 
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Old 12-31-14, 09:48 AM
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So you think it could be a bad switch? Sorry but it is hard to get a tech out this time of year and we are sweating it up!!!

My switch doesn't have a nut on it like the ones I see online, it looks as if it is soldered onto the top.
 
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Old 01-01-15, 06:32 PM
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Except for rusting away and leaking refrigerant, I rarely see them fail.
It is much more likely that you are low on refrigerant. The most common location for a refrigerant leak is the indoor coil.

Running a unit without enough refrigerant can damage the compressor, but you can temporarily bypass the switch to verify if it is cycling the compressor.

If you are cycling on the pressure switch you should call in a professional as we do not give instructions on charging up a refrigerant system.
 
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Old 01-01-15, 07:10 PM
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ok great. its possible i need and charge --- and i wouldnt ask how either... just wanted to confirm that is the most likely explanation!!
 
 

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