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-   -   AC Condenser (compressor and fan) can't start (http://www.diychatroom.com/f17/ac-condenser-compressor-fan-cant-start-142188/)

rliu 04-30-2012 08:56 PM

AC Condenser (compressor and fan) can't start
 
3 Attachment(s)
My 5 Ton AC condenser worked well last year but it is not working this year.

Both compressor and condenser fan are not running. The situation is below:
1. There is a AC power 110V between 2 hot lines on the contactor input terminals before turning on the AC. But this power is gone after turning on AC (24 V on). So both motors can't start.
2. When turning off the AC (24 V off), the 110 V is back.

What's wrong with this problem? Somewhere short? Relay bad?

Are all wires connected correct (see attached picture and diagram)?

Brand: Bryant
Product: 561CJX060000AAAA
Model: 561CJ060-A
Serial: 2300E23243
(see attached model plate)

Please advise, thanks.

Rick

carmon 04-30-2012 09:00 PM

you require 230 vac at the line side of the contactor...:eek:

rliu 04-30-2012 10:01 PM

I know the compressor is running at 230V. But each line in is 115V from the power circuit. How can get 230 between 2 input lines?

Doc Holliday 04-30-2012 10:14 PM

You need to check across one leg to the other, from one terminal to the other at the contactor, and see if you have 240-ish volts. If not, you've got an electrical problem such as a bad breaker.

biggles 04-30-2012 10:22 PM

230V with meter on both in coming line wires to the top of the contactor...and 24Vs on the 2 blue wire nuts.witht he condenser disconnect off that contactor should pull in from a call for cooling from the stat....don't check the incoming 230 to ground check between legs each 115V to ground

Doc Holliday 04-30-2012 10:28 PM

Also, do you have an electrical disconnect at the unit, with fuse perhaps? Check across the poles there as well.

rliu 04-30-2012 11:18 PM

So you mean between 2 black lines to the input of contactor should be 220vac, but I measured it is 110vac only. I'll check it on the circuit beaker. But I wonder why this 110vac gone when turning 24v switch on? Will this problem go away when the 220vac is normal? Thanks.

Doc Holliday 05-01-2012 01:54 AM

Quote:

Originally Posted by rliu (Post 911551)
So you mean between 2 black lines to the input of contactor should be 220vac, but I measured it is 110vac only. I'll check it on the circuit beaker. But I wonder why this 110vac gone when turning 24v switch on? Will this problem go away when the 220vac is normal? Thanks.

it should as far as the condenser being able to run but outside of the voltage problem who can tell..?

You're missing one leg of 120v.

rliu 05-01-2012 06:58 PM

I found one input line burned in the circuit beaker box but don't know why.
Question:
Is my compressor still good as the follow measurement?
CR = 0.4 ohm (blk-yel)
CS = 1.9 ohm (blk-blu)
SR = 2.2 ohm (blu-yel)
I have known SR=CR+CS, from this formula, compressor should be fine but I wonder why the resistance is so small between 3 terminals.
Please advise: Is the compressor good (not short)? It is 5 ton compressor.

carmon 05-01-2012 08:36 PM

it will be fine... try it you will find out fast...


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