Ac compressor, locked rotor fault.


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Old 02-19-18, 08:42 AM
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Ac compressor, locked rotor fault.

My home a.c. comprssor started short cycling. It will run for 30 sec or so then shut down. The diagnostic unit shows a locked rotor bearing. The compressor is still running and even cools. The amps on the compresor when it' ruining are 3.2 c, 3.6 r and then 4.3 on the s line. Is th start contact staying on or is there some thing else ? The daul capacitor checks out ok too.
 

Last edited by Sricci; 02-19-18 at 09:53 AM. Reason: Rewording
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Old 02-19-18, 08:51 AM
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Welcome to the forums.

Not sure how you arrived at three amperage measurements but they are incorrect or extremely low anyway. A model number would be helpful here.

You're asking us about the contactor

Is the contactor staying closed and the compressor is failing or is the contactor also opening causing the compressor to stop running ?

It sounds to me like the contactor is opening indicating a low refrigerant charge.
 
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Old 02-19-18, 09:50 AM
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Model RARL-024JAZ
It's a two stage two ton unit.
amp reading came off of the wires running through the digonostic control unit ( can't remember what it called it's self). It is what was giving the code 4 fault for a locked rotor. I'm gussing it was detecting the amps are off. Also guesing that the s wire is the start windings of the compessor and that it should be lower that the other two. Also guessing since the compressor is able to cool off the house on its very sort runs that it's not locked up.
 
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Old 02-19-18, 10:24 AM
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I'm still looking. This manual seems very close. No mention of a 4 fault code.

media/manuals/installation/RHEEMRASL-JEZ.pdf
 
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Old 02-19-18, 11:58 AM
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Here is the manual for the digonostic controller.

https://www.google.com/url?sa=t&source=web&rct=j&url=http://www.emersonclimate.com/documents/ae1385.pdf&ved=2ahUKEwjAjYmB4bLZAhVCwYMKHUrDBjsQFjAAegQIDRAB&usg=AOvVaw2EVsxDav0vN7ekRjuQcqWr

The amp readings defanently look low if the should be closer to 10.3.
 
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Old 02-20-18, 06:56 AM
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Had the a.c. guy come out yesterday. Low on refrigerant. He had o clue about the digonostic unit that is in it. After 4 lbs of refrigerant $180 and the $80 service call my a.c. was back up and running. After he told me that a had a single stage compressor and that everything needs replaced then left, I read the manual for the digonostic unit, reset the alarm and all is good now.
 

Last edited by Sricci; 02-20-18 at 06:56 AM. Reason: Spelling fix
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Old 02-20-18, 08:10 AM
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So where did he find the leak? And how did he repair it?
 
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Old 02-20-18, 08:45 PM
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4 lbs of refrigerant on a 2 ton system.

That's some sized leak. It's amazing it even started.
 
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Old 02-21-18, 05:37 AM
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He said that it would cost $600 to look for a leak. I kindly said no thanks. I will be checking it out this weekend. Could the guy have over charged it since he thought it was a single stage compressor instead of a dual stage?
 
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Old 02-24-18, 09:17 AM
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Locked rotor

This is a high amp draw and usually only happens when the rotor has seized. If it runs with those low amps, itís not a LRA problem. Is this a window shaker or a split system? If itís a window shaker, just toss it and get another one. If itís under 5 years old, it may still be under warranty.
 
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Old 02-24-18, 10:19 AM
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It' a central heat and air unit. If I had to guess I bet the digonostic unit has had that error code since it was put in. They had some issues when they put it in.
 
 

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