AC Question
07-15-2006, 01:12 PM
#1
Race Car
Thread Starter
AC Question
I just put in a used AC compressor and have a new receiver/drier waiting to go in. When all is in Can i recharge the system myself? What does it entail? What is the best way?
TIA
TIA
07-15-2006, 02:57 PM
#2
When all is installed, you need to pull a vacuum on the system. Pulling a vacuum as close to 30" of water column is preffered but actually not obtainable....so more like 22-28". Then let the system sit for an hour...wait (still hooked up) and see if the needle on your gauge drops below what you obtained. If it does, you have a leak somwhere.
You can also charge the system with nitrogen and listen for leaks but its harder that way because you may not hear the little ones especially in the evaporator under the dash. I would suggest replacing ALL orings in the system as possible. Most auto parts stores sell little kits for this and are pretty damn cheap.
Once its all good and no leaks, you can charge the system. This is the important part...
You need a fan in front of the car that pushes ~ 30 mph air into the condensor to simulate at speed temps. While youre charging, you want a 30-47* Delta T (temperature drop) from outside air temp and the air coming out of the vents.
If it ends up leaking refrigerant, your evap could freeze into a block of ice and then thaw leaving mass amounts of water near electrical connections causing hell for you.
The gauges that come with the walmart kits are ok for charging but since you opened the system, it is imperative that you pull a vacuum. Im not sure you can find a vacuum pump readily. So, you can get certified online at the EPA site. Its an open book test so its not all that bad.
With that certification, you can (maybe) rent a vacuum pump or ($$$) buy one if you plan on doing this for friends and family alot.
Finding an automotive HVAC fan that pushes 30 mph air is a bitch too. But you can find one in a 200K BTU furnace. So, ask around your local HVAC companies if you can rumage around their trash for furnaces you can steal one from.
I got all my equipment from Ebay, local HVAC companies, and supply houses like Johnstone.
The last peice of equipment is some good gauges. These are R134/R12 gauges and are cheap. They will let you pull the vacuum as you will hook up the yellow hose from your gauges to the vacuum pump and the red (high side) hose to the high psi port and the blue (low side) to the suction line port. The gauge will tell you how much vacuum you are pulling. When buying a set from a HVAC supply house, they will suggest purchasing oil for the pump and the small adapter for forein cars. Really cheap stuff and youll have it all forever. You can do all your neighbors cars and charge them!!!
Note: Be DAMN carefull when accessing the suction line by the compressor. Wear googles, gloves, etc. You can be burned by this stuff and need to go to the hospital! It will leave a mark for life. Be Careful!
Hope this helps and GOOD LUCK!
You can also charge the system with nitrogen and listen for leaks but its harder that way because you may not hear the little ones especially in the evaporator under the dash. I would suggest replacing ALL orings in the system as possible. Most auto parts stores sell little kits for this and are pretty damn cheap.
Once its all good and no leaks, you can charge the system. This is the important part...
You need a fan in front of the car that pushes ~ 30 mph air into the condensor to simulate at speed temps. While youre charging, you want a 30-47* Delta T (temperature drop) from outside air temp and the air coming out of the vents.
If it ends up leaking refrigerant, your evap could freeze into a block of ice and then thaw leaving mass amounts of water near electrical connections causing hell for you.
The gauges that come with the walmart kits are ok for charging but since you opened the system, it is imperative that you pull a vacuum. Im not sure you can find a vacuum pump readily. So, you can get certified online at the EPA site. Its an open book test so its not all that bad.
With that certification, you can (maybe) rent a vacuum pump or ($$$) buy one if you plan on doing this for friends and family alot.
Finding an automotive HVAC fan that pushes 30 mph air is a bitch too. But you can find one in a 200K BTU furnace. So, ask around your local HVAC companies if you can rumage around their trash for furnaces you can steal one from.
I got all my equipment from Ebay, local HVAC companies, and supply houses like Johnstone.
The last peice of equipment is some good gauges. These are R134/R12 gauges and are cheap. They will let you pull the vacuum as you will hook up the yellow hose from your gauges to the vacuum pump and the red (high side) hose to the high psi port and the blue (low side) to the suction line port. The gauge will tell you how much vacuum you are pulling. When buying a set from a HVAC supply house, they will suggest purchasing oil for the pump and the small adapter for forein cars. Really cheap stuff and youll have it all forever. You can do all your neighbors cars and charge them!!!
Note: Be DAMN carefull when accessing the suction line by the compressor. Wear googles, gloves, etc. You can be burned by this stuff and need to go to the hospital! It will leave a mark for life. Be Careful!
Hope this helps and GOOD LUCK!
07-15-2006, 03:08 PM
#3
http://www.epa.gov/Ozone/title6/609/recharge.html
The above site is the EPA's site for more info on the matter.
http://www.epatest.com/
This is the EPA's site for certification. There's a fee for certification. Scroll down to "Section 609" and click on "View the 609 manual" then after you got that down (or minimized), click on "Take the 609 exam."
Its a 3 hour exam so.....make sure you have time to do it.
After that you can buy r12 (goodluck finding it), r134a, and any other refrigerant that companies come out with! Including all the equipment.
The above site is the EPA's site for more info on the matter.
http://www.epatest.com/
This is the EPA's site for certification. There's a fee for certification. Scroll down to "Section 609" and click on "View the 609 manual" then after you got that down (or minimized), click on "Take the 609 exam."
Its a 3 hour exam so.....make sure you have time to do it.
After that you can buy r12 (goodluck finding it), r134a, and any other refrigerant that companies come out with! Including all the equipment.
07-17-2006, 11:19 AM
#4
Advanced
Join Date: Dec 2003
Location: Brandon, MS
Posts: 76
Likes: 0
Received 0 Likes
on
0 Posts
I just went through this on my Honda and it went bad. My new compressor locked up after two months. I installed a new compressor, drier and expansion valve. I took the car to a local car car clinic for them to pull a vacuum and refill. They did but they didn't document it on my ticket so my warranty is being denied. Plus, I did not flush the system prior to vacuum. I was unaware of this so I urge you to do this. The contamenants that missed up your old compressor is still in your system. It's better to be safe than sorry. I've read many post in the a/c area and this is often overlooked. Good luck.
07-17-2006, 11:36 AM
#5
Three Wheelin'
Join Date: Mar 2002
Location: nj
Posts: 1,296
Likes: 0
Received 0 Likes
on
0 Posts
Originally Posted by apen749
I just went through this on my Honda and it went bad. My new compressor locked up after two months. I installed a new compressor, drier and expansion valve. I took the car to a local car car clinic for them to pull a vacuum and refill. They did but they didn't document it on my ticket so my warranty is being denied. Plus, I did not flush the system prior to vacuum. I was unaware of this so I urge you to do this. The contamenants that missed up your old compressor is still in your system. It's better to be safe than sorry. I've read many post in the a/c area and this is often overlooked. Good luck.
07-17-2006, 02:10 PM
#6
Instructor
Join Date: Sep 2005
Location: Dacula, GA
Posts: 157
Likes: 0
Received 0 Likes
on
0 Posts
You do not need certification to rent or buy a vacuum pump, only to buy refrigerant. In many states, you can buy 134a cans at Wal-Mart without certification. I strongly second 944-LT1's comments about pulling a vacuum (evacuate). With a good vacuum pump, you will get very close to the 29" and it is important that you do so. Do not buy one of those compressed-air operated vacuum pumps, they will not pull down to a deep vacuum. A good vacuum pump is not rated by inches of mercury but is instead rated in microns. Only a deep vacuum is enough for all the moisture to boil off and get out of the system prior to refill.
If you did have a massive failure of the compressor that threw bits of metal in to the system, it is important to flush it out and get rid of these contaminents to the extent possible. Some recommend replacement of the condensor in this case since it can be difficult to remove all of them.
I'm not sure why you would need a fan to simulate 30mph for charging (maybe for testing). If you're filling an empty system, you can charge the prescribed weight.
If you did have a massive failure of the compressor that threw bits of metal in to the system, it is important to flush it out and get rid of these contaminents to the extent possible. Some recommend replacement of the condensor in this case since it can be difficult to remove all of them.
I'm not sure why you would need a fan to simulate 30mph for charging (maybe for testing). If you're filling an empty system, you can charge the prescribed weight.
Trending Topics
07-31-2006, 11:13 AM
#8
Rennlist Member
Originally Posted by Jeeper31
Do I have to vacuum the system out?
Explanation below.
Shouldn't it be empty since it was all opened? (Hope this is not a stupid queston)
