Need to recharge central ac unit, how to??????

rosehaven · #1 05/27/06, 11:04 AM

Husband needs to recharge the central AC unit in our home. We just moved here and no cold air coming from unit. The home inspector stated it needed to be recharged but don't know how or what is needed. Any help would be greatly appreciated.

Blessings...........april

**Cabin Fever** · #2 05/27/06, 11:28 AM

I think that you're gonna have to bite the bullet and hire an AC technian to do this job on accounta you need a license to buy Freon.

agmantoo · #3 05/27/06, 02:20 PM

For a small fee you can take a test on the internet and get your license to obtain freon.
http://www.epatest.com/
They send a nice certification card.

Jack in VA · #4 05/28/06, 07:55 AM

OK, first you get certified by the EPA to handle Freon. Then you try and find someone to sell you some.( $8.00-$20.00 per pound, minimum 30 pound can)Then you get a tank of dry nitrogen and the appropriate fittings to pressurise the system to check for leaks. If you find a leak and it's in a solder joint , you get yourself a oxy/acetylene set-up and some silver solder and braze the offending leak. Then you get vacuum pump ($400-$600)and evacuate the system. Then using your refrigerant gauges($50.00) you charge the system. Best way to do this is to weigh it in(scale-$200-$300). Of course you know the EXACT amount to put in. Make sure you don't allow any Freon to escape into the air, as this is subject to a $20000 fine and/or 5 years in jail. Have fun.

tyusclan · #5 05/28/06, 10:12 AM

Are you sure the compressor is running? If not, recharging the unit is not going to help. You could have a bad compressor, or a bad contactor, or a burned off wire, or a bad condensing fan motor, or a bad thermostat that is not telling the compressor to run. Any of these will have "no cold air" in the house. If your husband is handy with equipment, he can pick up a basic book on a/c & refrigeration that will walk him through how to test for these things. If not, you'll come out better to get a reputable a/c company out to check it out for you.

LvDemWings · #6 05/28/06, 10:16 AM

If this is a window or wall unit it will probably be cheaper to buy a new one. Most window and wall units were not built to be recharged and the ac tech can fix the unit and add a thing to allow it to be recharged but the cost per hour plus materials will hurt.

goatlady · #7 05/28/06, 04:27 PM

LDW, she SAID clearly it was a CENTRAL UNIT which is never a window unit! Can you tell it's pet peeve when folks do NOT read original posts and respond inappropriately?

Quint · #8 05/28/06, 05:23 PM

lol remember back when freon was so cheap that you could buy BB machine guns that ran off the cans of it you bought for a buck or two at the auto parts store? The freon was cheaper than the BBs.

dale · #9 05/28/06, 05:28 PM

Now many A/C units the compresser will not run untill a certian amount of freon is in the unit to save it from running with out freon and ruining it.

there is a switch that will allow it to work when a certian amount is put in

dale

LvDemWings · #10 05/28/06, 05:41 PM

Goatlady. Many homes have a wall unit as the central ac. It is most common in older homes or historic homes that have boilers and wouldn't have duct work. Flexable tubing is used to feed the cool air into other rooms. I added the information about window units for the benefit of others reading this thread who might be having similar problems.

tyusclan · #11 05/28/06, 07:32 PM

Quote:

Originally Posted by dale

Now many A/C units the compresser will not run untill a certian amount of freon is in the unit to save it from running with out freon and ruining it.

there is a switch that will allow it to work when a certian amount is put in

dale

It's called a low-pressure cut-out switch.

hunter63 · #12 05/29/06, 08:06 PM

We still haven't found out if the compressor runs or not.
Does the outside condensing fan run?

I have had calls that were, chewed thermostat wire at the outside unit, bugs in the contactor (not allowing it to close), burned off wires, fuse blown etc.
So, first see if there is power at the out side unit, then see if the compressor runs,(you can push in the contartor manually) if not a charge isn't going to help.

You can ohm a compressor

ower off, disconnect wires to the compressor, use ohm
meter to test between the three wires, should read something like 2-4-6 ohms
Then check to ground, if you have a reading it's shorted, if when you test between the three wires you don't get a reading in will be "open" (broken or burnt wire).
Most compressors are capacitor start, that might be bad, but need capacitor checker to test that.
Let us know.

fixer1958 · #13 05/29/06, 09:37 PM

I've been nursing the piece of crap I have now for 15 years. After a swift kick to the condenser to get it to switch from heat to AC (heat pump) it wouldn't do it this year. I finally bit it and am getting upgraded this wednesday (6k later). I'm ever so glad to see this thing go. Heat pumps are useless where I am. This one is anyway. I have never found anyone that knew how to service it and had to do most of it myself. One guy spent 4 hours checking circuits and talking to himself ( I could hear him in the basement ) and charged $35 because he didn't know what to do.
Call a tech if it's it's a regular central air system and you will save a lot of headaches.
If not, rip it out and have a bon fire and then run over it with a tractor.
I have issues with house AC.

DrippingSprings · #14 05/29/06, 10:27 PM

I think some folks need to brush up on ac techniques and laws and especially prices. BTW you dont have to buy a 30 gal cylinder. I added some to mine yesterday with a regular set of gauges and three 8 dollar cans of coolant that required no license etc to purchase.

Check to make sure the fan out on the unit is coming on. Its usually the culprit. Also clean all vegetation etc around it and clean the coils with a toilet brush and water.

MoonShine · #15 05/30/06, 10:19 PM

I was just saying yesterday that I was going to have to buy some freon to charge the A/C up. I guess everyone's thinking about this subject...it's been really hot here!

wvpeach1963 · #16 05/30/06, 11:48 PM

Most Auto parts stores have the disposable freon canisters for rechargeing car Air.

Couldn't those be used on home airs?

JackDeePeyton · #17 05/31/06, 01:31 AM

I helped work on a unit this weekend, everyone and his brother had looked at it, with no luck. Not to say that I am the sharpest knife in the drawer, but found a wire that had been chewed thru by mice (?). Sometimes all it takes is a little bit of common sense and sometimes it's time to call someone who knows what they are doing. Best of luck with you problem, rosehaven.

tyusclan · #18 05/31/06, 05:15 AM

Quote:

Originally Posted by wvpeach1963

Most Auto parts stores have the disposable freon canisters for rechargeing car Air.

Couldn't those be used on home airs?

NO! Automotive A/C uses R134A. Your home A/C uses R22, and they are NOT interchangeable.

DrippingSprings · #19 05/31/06, 10:03 AM

but r22 is available in the small cans