A/C click with on, inside turns on but outside doesn't, capacitor replaced last.

My AC unit is about 8 years old. When you turn the tstat to on, the outside unit clicks once. The fan spins freely, but it won't start. Last summer I had the problem that I would turn the AC on, hear the click, but the outside unit wouldn't go on. When I turned the fan, the fan would start up and replacing the capacitor did the trick. Now spinning the fan does nothing (though it spins freely). Heat probably worked a week or two ago.

 

Does the compressor on the outside unit kick on and run?

 

When I turn on the AC at the t-stat I hear a single click in the outside unit. Nothing else happens.

 

First thing you need to check is that you are actually are getting 240 volts to the outside unit you may have a bad disconnect outside or a bad breaker in your main panel. I have seen some of the ElCheapo outside disconnect panels that have the little pull out sections with the little blades that will not make contact or you could have fuses or breakers out there. Verify that you are getting power first as typically the compressor will kick in. I think that the click you hear is the contactor pulling in as it is powered from the air handler inside your house seperatley from the outside condensing unit

 

I do have a pull out section outside with two fuses. I checked both fuses with a voltmeter and they both looked stable. What is the easiest way to make sure I am getting 240V outside?

 

the only way to do a true test is to pull the units access panel and check both sides of the contactor to verify that power is getting to the contactor and also thru the contactor. If you are not comfortable working around hot equipment you will want to get someone that is familiar and experienced, no need to get your self hurt or killed to save a few bucks here. Perhaps the safest thing you could do would be to disconnect all power and simply replace the capacitors and give that a try. What sounded unusual was that neither the fan nor the compressor would start a lot of times only one side of the dual capacitor will go bad and the compressor or fan vice versa will operate normally although it is possible that both sides of a dual capacitor can die at the same time. Be careful out there men

 

I checked both sides of the contactor. There is a bit over 240V coming in, but I couldn't get a read on the other side of the contactor so perhaps it is the contactor that is bad. I've uploaded photos here:

http://s282.photobucket.com/albums/kk259/marzomarz/

When I tested the yellow and black wires on the contactor, the voltmeter read a very low single digit number.

 

looks like you have a single pole contactor there, so the one side (without the section that you push in) should have power str thru the contactor at all times. Check the heavy yellow wire to ground and you should have 120 volts. Once that is verified use a insulated screwdriver to push the center section in on the other side if your units fan starts and after a short delay the compressor starts then we have verified that the high voltage power supply is good. You could possibly have a low voltage problem, lets make sure that the thermostat is calling for cooling and then we would want to check between the small brown wire on the one side of the contactor to the small yellow wire on the other side of the contactor, it should read approx 24 volts, 24 volts between those two wires activates a magnet that pulls the contacts together. Post back when you get a chance. There are a lot of things that could cause a low or no voltage problem at the contactor including a bad thermostat/condensate overflow switch tripped/high or low pressure switch tripped/poor connection in the thermostat wiring. After a few more checks maybe we can narrow it down. We need to know if you are getting the 24 volts at the contactor magnetic coil to proceed logically. If you are in fact getting 24 volts to the contactor and it is not pulling in we simply need to replace the contactor itself. Hang in there, if you have enough time we will get to the bottom of the problem. I hope it is not real Hot there lol

 

Thanks so much for the reply - I really appreciate it. Just want to make sure I follow the correct steps. I've uploaded a new photo with labels here:

http://s282.photobucket.com/albums/k...lectricity.jpg

Based on your description, it sounds like I want to first test the large yellow wire on ground for 120V (as labeled) and if I get 120V then I want to test the brown wire on the top against one of the yellow wires for 24V. Can you tell me which one of the yellow wires?

 

Well first lets test yellow3 to ground and it should show 120 volts. Then lets push that center section in and make sure that the fan and compressor do actually run. If they do then we move on and test brown to yellow2 and we should have 24 volts there let me know what you come up with.

 

Ok. 240V in and 120V out. When I compress the switch on the contactor the fan immediately starts up. I then tested the brown to the yellow and got nothing.

 

I to had an issue with my compressor. Once it got the signal to uh compress, it would click and mebe hum a bit, but no turn and certainly no cool. 80+ in the house and well I've got the certain kinda feeling going on. ewww Finally, after looking at this thread, I found the junction box outside by the compressor, once I got it open there were two big (really big) fuses (that was four inline before the compressor if you count the ones on the inside unit). These two fuses were situated in a dual fuse unit, so you could just yank the handle and pull them both out. Long story wrapped up, the fuse carrier was jostled, not out not in and once I reset it (pulled it out and slapped it back in) I fired up the system and all was right with the world. Dunno how they slipped out, nothing touched that box to my knowledge but that was the issue.

Compressor clicks mebe hums a bit but wont turn, answer outside fuse box had fuses that were loose, not bad or obviously out, just loose.
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