changed contactor on a/c unit and still wont turn on


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Old 08-21-12, 05:14 PM
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changed contactor on a/c unit and still wont turn on

I will rephrase from subject line i can manually push the button and the condenser and fan will turn on but not by t-stat i changed the other contactor because it looked like it was burnt on the pole post's .

But it all happened this morning i was already at work and my wife said the the air conditioner was fine, i got home early from work and she turned the t-stat down cause we were going to w-mart. when we got back the blower was on but it wasnt getting cool so we checked outside unit and it wasnt on. i pushed the old contactor button and it turned on so naturally i thought it was the contactor being bad and not staing down. Nope i bought a new one and still no pulling down of the contactor button.

Please help whole unit wors and cools down just not until you manually push down the contactor button .


is it possibly the capasitor ?


thanks in advanced
 
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Old 08-21-12, 05:19 PM
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First thing to do is check for 24 volts (more or less) at the contactor coil terminals after a five minute delay from the thermostat calling for cooling. If no power then check the low voltage wiring from the furnace (air handler) to the condensing (outside) unit.
 
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Old 08-21-12, 05:23 PM
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are you talking about the to and fro hot wires when the button is pushed or from the circuit board wires
 
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Old 08-21-12, 06:02 PM
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The wires that are most likely on the side of the contactor. The ones that come from the air handler. Probably fairly small size.
 
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Old 08-21-12, 06:14 PM
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You have a circuit board on the outside unit? That im willing to bet is the problem.
 
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Old 08-21-12, 07:11 PM
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yes i have a circuit board on the outside unit which sends the contactor the pull and push i beleive right now i need to figure out where to get it


should the a/c place where i got the contactor probably has it correct
 
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Old 08-21-12, 08:47 PM
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I'm more inclined to think your unit has a terminal board, not a circuit board. Merely a place to terminate all the wiring.

...which sends the contactor the pull and push i beleive...
The contactor does not receive a "pull and push" but a 24 volt AC signal to the coil of a solenoid. When the coil is energized the contactor closes the high voltage (240 volts AC) to the compressor and the cooling fan motor. When the 24 volt signal is off a spring opens the contacts on the high voltage turning everything off.

Post a few pictures of your contactor and this "circuit board" and we can better help you.
 
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Old 08-22-12, 03:19 AM
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[HR][/HR]it is the board where the t-stat wires hook up to then a bunch of lettering's on below where other wires hook up like t-1 and t-2

but when i get home from work i will post some pics

also let me say something when the unit is turned on by tstat

the contactor button clicks then bounces like it wants to pull down but just cant
 
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Old 08-22-12, 11:45 AM
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Before you get a board you need to verify it is the board by jumping 24 volts straight to the contactor with terminals 'y' and 'c'
 
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Old 08-22-12, 05:21 PM
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jump 24 volts to the y and c that is on the board correct
 
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Old 08-22-12, 06:33 PM
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Here are my pics of my a/c unit board cpacitor and contactor


 
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Old 08-22-12, 07:18 PM
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Yep, that's a circuit board. Sorry for doubting what you wrote.

With the power off (pull the local disconnect switch) you need to carefully move the wires around and look on the contactor for the "coil volts) numbers. Most common is 24 volts AC but the wiring on the coil terminal visible (the terminal on the right side with the black wire) leads me to believe it could be a 240 volt coil. Check this black lead and also the one on the terminal on the left side (obscured in the picture by the wiring bundle) carefully for breaks, especially where it is connected to the push-on terminals of the contactor and also at the circuit board.

Look carefully at the low-voltage wiring coming from the house to the unit. It appears to connect to the circuit board on the lower left side.
 
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Old 08-22-12, 08:33 PM
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nah no worries on the doubt pictures are thousand words so i put em

now so you dont think its the board or capacitor because the contactor is new

so does the 2 side prongs that come from the board give the ok to the contactor to tell the fan condensor to work

the tstat turns on the blower in the house just not the outside so its possibly not the board cause thats bout 155-200 dollars
 
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Old 08-22-12, 08:54 PM
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yeah jump y and c from the circuit board, where the wires come into the board, and attach them to each side(left/right) of the contactor where 24V goes. But do note, that this will only fix the ac and not the heat.
 
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Old 08-23-12, 03:21 AM
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ok so this is a heat a/c outside unit or is the heat in the inside blower
 
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Old 08-23-12, 10:59 AM
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its a heat pump, it will give you heat from the outside unit, but you do have backup heating elements inside the air handler/furnace
 
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Old 08-23-12, 07:49 PM
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ok just got off work and jumped y and c and it works through the tstat

now what does that mean what is broken?
 
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Old 08-24-12, 11:45 AM
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Damn I'm good. It means the circuit board on the outside unit has gone bad. The circuit board is only used for heating purposes.
 
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Old 08-24-12, 07:51 PM
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i got ya thats cool for now i will use the jumper untill i can get the board i seen a site or i will try my local a/c shop see if they can get it for cheaper then $155


i appreciate this very much you helping me out i am pretty savvy but not a/c savvy

thank you
 
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Old 08-25-12, 02:05 AM
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tired when i wrote it i want to thank you all for helping me
 
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Old 08-25-12, 09:19 PM
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I suggest you try cleaning all those corroded connections to the circuit board before buying a new board. Reseat connectors and you could spray them with a contact cleaner. I use DeOxit but it is over priced. You could check the circuit board for cold solder joints. They can go bad from excessive heat and/or vibration. Reflow any that look bad if you know how to solder, I would not touch them if you don't know how. You need to use a low power iron with small boards like these.
 
 

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