Compressors wont power on in a 2 fan A/C commercial system


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Old 01-16-17, 08:53 AM
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Compressors wont power on in a 2 fan A/C commercial system

The circuits look fine the capacitors we talking are brand new shows power I think the wiring is wrong it's an old system with a lot of jumpped wires everything runs fine but the compressors won't power on
 

Last edited by Fishtales0017; 01-16-17 at 09:40 AM.
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Old 01-16-17, 09:38 AM
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Thread moved to Air Conditioning forum.
 
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Old 01-16-17, 10:07 AM
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Make and model numbers would help.
 
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Old 01-16-17, 10:08 AM
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Not going to be able to help you without more information than that.
Make and model.
Pictures at the very least otherwise we're just guessing. http://www.doityourself.com/forum/el...-pictures.html
 
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Old 01-16-17, 12:10 PM
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Cant figure how to upload pics from my phone
 
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Old 01-16-17, 12:59 PM
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Do you have a model and serial number? Do you have a meter and tools? Are you ok working on live electricity? Commercial can mean 3 phase power up to 480 VAC so you need to take proper precautions with safety.
The unit could be out of refrigerant and a low pressure control is open. Is there a low pressure control and is it open or closed? Do you have line voltage? Control voltage? Is it calling to run?
 
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Old 01-16-17, 01:02 PM
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If your phone pictures are large files, as most are, they will be too big to post directly to the board.
 
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Old 01-16-17, 02:40 PM
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Old 01-16-17, 02:56 PM
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Old 01-16-17, 02:59 PM
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You have a carrier package unit. That unit features a dead mans leg on the electrical circuit so beware, it's always live and it can easily kill you. Is it calling for cooling? Control voltage is?
 
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Old 01-16-17, 03:36 PM
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Well since i dont know much about this stuff i dont want to die i just know when i turn it back on everything runs. Blower motor and both fans. But the compressor is dead. We had a guy come fill it. It was working fine. The next day the fan went out we changed the motor and that works now but the compressor dont.
 
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Old 01-16-17, 03:40 PM
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Fill it? As in refrigerant? So where was the leak?
 
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Old 01-16-17, 04:02 PM
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Im not sure if there is a leak could have been years since it was charged. Im haveing a guy come this week to check it all out. Thanks for the help anyway im way out of me element here. I no there is a cap missing to where a gauge goes not sure it its leaking out of there or not. Anyway thanks for the help
 
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Old 01-16-17, 04:10 PM
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Refrigerant is not a consumable material. So if the unit needs charged, there's a leak. Unless it's been improperly diagnosed and it didn't need refrigerant
 
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Old 01-17-17, 08:07 AM
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So if there is a leak that could be a reason for the compressor not to run? I will put a work order in for a possible leak so they bring the right material this is a place where only inmates do the work with a license professional
 
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Old 01-17-17, 09:38 AM
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Low or no refrigerant pressure will open the low pressure safety switches, if they are installed on this unit. I see high pressure controls.
 
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Old 01-17-17, 10:07 AM
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This forum is also out of it's element for what you are asking.

We are geared towards homeowners working in a residential setting.
This air-conditioner is not overly complicated but the problem will require assessing the sealed refrigeration system which we do not discuss on these forums.

You need to get a qualified and competent tech to work on your unit.
As said, refrigerant never wears out and will last forever unless there is a leak.
Today's environmental laws require refrigerant leaks to be repaired and if you were the victim of a gas'n-go you need a new tech.
 
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Old 01-18-17, 05:19 AM
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To respond to the OPs last post, any decent tech with their EPA license will have a usable amount of the correct refrigerant with them. There should be no need to call and confirm. The location is no big deal either as long as their company does the appropriate background checks or whatever else is needed. We do prison work and have to have updated background checks every 6 months.
Now, to anyone working on one of these units that's unfamiliar with commercial work, be careful. These are 3 phase units, and 3 phase is its own animal. Now, what carrier has gotten into a habit of doing for a long time is using a 3 phase power supply with a dead mans leg, otherwise known as a hot leg. Note how there's only 2 pole contactors in the control compartment-the third leg is always hot. So if you look up and see your compressor contactor is open, there's still live high voltage on the peckerhead of the compressor!!! This is also true for the 480 V units as well. It will be the same with most 3 phase loads inside these units. So the only way of doing electrical troubleshooting in a safe manner is lockout/tagout. I was on a job one time and an electrician got hit with a dead mans leg. He wound up getting airlifted from the site to the hospital. Use extreme care!
Also, before any further work is done, check the heat exchanger if this is a gas pack. These units have a nasty habit of rotting at the tube bends. Take the end cover off and the heat exchanger is right in front of you.
 
 

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