Ac compressor, locked rotor fault.
#1
02-19-18, 08:42 AM
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
#2
02-19-18, 08:51 AM
Group Moderator
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.
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.
#3
02-19-18, 09:50 AM
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.
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.
#4
02-19-18, 10:24 AM
Group Moderator
I'm still looking. This manual seems very close. No mention of a 4 fault code.
media/manuals/installation/RHEEMRASL-JEZ.pdf
media/manuals/installation/RHEEMRASL-JEZ.pdf
#5
02-19-18, 11:58 AM
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.
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.
#6
02-20-18, 06:56 AM
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
#8
02-20-18, 08:45 PM
Group Moderator
4 lbs of refrigerant on a 2 ton system. 
That's some sized leak. It's amazing it even started.
That's some sized leak. It's amazing it even started.
#9
02-21-18, 05:37 AM
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?
#10
02-24-18, 09:17 AM
Locked rotor
This is a high amp draw and usually only happens when the rotor has seized. If it runs with those low amps, it’s not a LRA problem. Is this a window shaker or a split system? If it’s a window shaker, just toss it and get another one. If it’s under 5 years old, it may still be under warranty.
