DIY Chatroom Home Improvement Forum

DIY Chatroom Home Improvement Forum (http://www.diychatroom.com/)
-   HVAC (http://www.diychatroom.com/f17/)
-   -   AC stopped blowing cold air (http://www.diychatroom.com/f17/ac-stopped-blowing-cold-air-186690/)

miamimike88 09-08-2013 05:28 PM

AC stopped blowing cold air
 
3 Attachment(s)
Hi all,

This past Friday, my ac was on but stopped blowing out cold air. I checked the unit outside and the fan was not moving. I tried giving it a jump by moving it with a stick, but no luck.

I researched and I come to the conclusion that it could very well be the capacitor. I opened up the unit to take a look. If I were to go about replacing the capacitor, would it be the black on with 2 terminals? But then I saw another capacitor hanging underneath with 3 capacitors? So does this mean the unit has dual capacitors, and if so, which do I replace?

Also, where can I buy capacitors? I keep hearing these places but they only seem to sell to contractors and such.

thanks so much. It's no fun not having cold air in 90 degree weather.

HVAC1000 09-08-2013 08:42 PM

Quote:

Originally Posted by miamimike88
Hi all,

This past Friday, my ac was on but stopped blowing out cold air. I checked the unit outside and the fan was not moving. I tried giving it a jump by moving it with a stick, but no luck.

I researched and I come to the conclusion that it could very well be the capacitor. I opened up the unit to take a look. If I were to go about replacing the capacitor, would it be the black on with 2 terminals? But then I saw another capacitor hanging underneath with 3 capacitors? So does this mean the unit has dual capacitors, and if so, which do I replace?

Also, where can I buy capacitors? I keep hearing these places but they only seem to sell to contractors and such.

thanks so much. It's no fun not having cold air in 90 degree weather.

The vertical one is a dual cap. The black plastic one is a start vapid start with the dual cap first but recommend replacing both. There is also a start relay in there but that only affects the compressor starting. Before u replace make sure u check the ratings on it. You don't need to be a contractor to buy from Graingers. Also most supply houses (around here) will sell to non-contractors but they just get charged a bit more

miamimike88 09-10-2013 02:12 PM

1 Attachment(s)
Quote:

Originally Posted by HVAC1000 (Post 1239631)
The vertical one is a dual cap. The black plastic one is a start vapid start with the dual cap first but recommend replacing both. There is also a start relay in there but that only affects the compressor starting. Before u replace make sure u check the ratings on it. You don't need to be a contractor to buy from Graingers. Also most supply houses (around here) will sell to non-contractors but they just get charged a bit more

Thanks for the info! So I went to Graingers to get a replacement for the black one. Question: the capacitor on the bottom is the new one I bought, does it matter that it doesn't have the that thing it the middle connecting the 2 terminals? Would it make a difference?

thanks!

firedawgsatx 09-10-2013 02:48 PM

1 Attachment(s)
I believe you bought the wrong capacitor. You bought a start capacitor that assists in starting the compressor. Since you stated your fan was not coming on you should have replaced the run capacitor I labeled "fan" in the photo. It appears that at sometime someone used a dual run capacitor to only run the compressor and a separate run capacitor for the fan. It looks like a universal fan motor wiring and that is probably why. You should be good (if the fan is the only problem) if you replace the run capacitor with the two brown wires going to it. Make sure to replace it with a capacitor with the same specs.

Before you replace the capacitor though you probably need to check some other items:

You stated that when you checked the unit the fan was not moving. Was the compressor running? Was there power to the disconnect? Is the inside blower working?

yuri 09-10-2013 03:30 PM

firedog is correct but to simplify it to a few words that a non Pro can understand. replace both of the other ones as they can affect the fan motor if either one is shorted open or very weak. Americanhvacparts.com is a good site.

HVAC1000 09-11-2013 01:20 AM

One more quick note. When replacing caps make sure they are secure won't move around at all and the metal terminals won't short out on any other metal surfaces. I came across one the other day where the last guy there replaced fan motor and cap but did not secure cap. So it shifted in cabinet from vibrations and blew a small hole in the dual capacitor which preceded to leak its oil all over the compartment on unit luckily it tripped breaker before any real damage started

miamimike88 09-11-2013 09:05 AM

Quote:

Originally Posted by HVAC1000 (Post 1240546)
One more quick note. When replacing caps make sure they are secure won't move around at all and the metal terminals won't short out on any other metal surfaces. I came across one the other day where the last guy there replaced fan motor and cap but did not secure cap. So it shifted in cabinet from vibrations and blew a small hole in the dual capacitor which preceded to leak its oil all over the compartment on unit luckily it tripped breaker before any real damage started

Wow, thanks for the heads up! I'll be sure to secure it I put it in.

yuri 09-11-2013 09:08 AM

yeah, use metal perforated strapping.

miamimike88 09-11-2013 09:12 AM

Quote:

Originally Posted by firedawgsatx (Post 1240296)
I believe you bought the wrong capacitor. You bought a start capacitor that assists in starting the compressor. Since you stated your fan was not coming on you should have replaced the run capacitor I labeled "fan" in the photo. It appears that at sometime someone used a dual run capacitor to only run the compressor and a separate run capacitor for the fan. It looks like a universal fan motor wiring and that is probably why. You should be good (if the fan is the only problem) if you replace the run capacitor with the two brown wires going to it. Make sure to replace it with a capacitor with the same specs.

Before you replace the capacitor though you probably need to check some other items:

You stated that when you checked the unit the fan was not moving. Was the compressor running? Was there power to the disconnect? Is the inside blower working?

Thanks for the info. I got new parts for the Start cap and run cap ("fan") and the compressor part will be coming in tomorrow. I'm going to install the 2 parts tonight and see what happens.

If I remember correctly, I didn't really hear anything, or at least I don't think I did from the outside unit. There was warm air blowing inside the house and the air handler was making noise but the outside unit didn't have much sound to it.

yuri 09-11-2013 09:16 AM

check for 220-240 volts across the incoming side of the contactor. not to ground.

miamimike88 09-12-2013 06:32 PM

Hey guys,

I just replaced the start and run capacitor ("fan") with new ones and when I went to go turn on the AC, I could hear the air handler going on but for the outside unit, nothing at all. No noise, no fan movement, nothing. I tried kickstarting the fan with a stick but no luck. I had ordered a new part for the compressor as well but hasn't come in yet (I put the old one back in).

Could it be the contactor? I don't have a multimeter at the moment to check the voltage but I could get one easily. If that's the case and I should check the voltage, how would I go about doing it? There's a pic earlier in the thread of the contactor. Which wires do I check and do I check it when the AC is on?

thanks again!

miamimike88 09-12-2013 06:32 PM

Quote:

Originally Posted by yuri (Post 1240650)
check for 220-240 volts across the incoming side of the contactor. not to ground.

Hi Yuri,

Which would be the incoming side of the contactor? And where exactly on the contactor do I check for it?

thanks.

firedawgsatx 09-12-2013 06:53 PM

1 Attachment(s)
Here is an image of the test points you will need to check with a multimeter. Be extremely careful as the 24oV is live and can be lethal!
Set the multimeter to 600VAC when testing the 240V test points. The incoming voltage is between L1 and L2 in the diagram. Place one lead on L1 and L2. It should be atound 240V

miamimike88 09-12-2013 07:36 PM

Quote:

Originally Posted by firedawgsatx (Post 1241168)
Here is an image of the test points you will need to check with a multimeter. Be extremely careful as the 24oV is live and can be lethal!
Set the multimeter to 600VAC when testing the 240V test points. The incoming voltage is between L1 and L2 in the diagram. Place one lead on L1 and L2. It should be atound 240V

Awesome diagram. Thanks.

As for the procedure of testing it (I wanna be careful cause I am aware of the danger of it):

1) Do I have the AC on or off?
2) How can I be sure when I place the leads that I won't get shocked? Are gloves recommended for using the multimeter?

firedawgsatx 09-12-2013 08:22 PM

To test the 240V the power has to be on. That is what makes it dangerous. Carefully place one probe of the meter on the L1 and the other lead on the L2 to get your reading. Just make sure the ground is dry and remove all rings, watches, bracelets, necklaces and etc and remove any loose fitting clothing. Gloves are optional. I prefer to work without them. After you test to see if you have 240V coming in you can do the other tests listed on the diagram. Don't hesitate to ask if you have any doubts. The first time you work with high voltages it is intimidating. But as you have more and more practice and get proficient you gain more confidence always remembering the danger and the need for strict focus.


All times are GMT -5. The time now is 12:00 PM.


Copyright 2003-2014 Escalate Media LP. All Rights Reserved