Charging the AC system

Reply Subscribe

Thread Tools

Search this Thread

May 26, 2007 | 01:44 PM

#16

wtroger

Cargo Master

Joined: May 2001

Posts: 3,208

Likes: 13

I agree if the system hasn't been opened and it has any pressure in it then you can charge it as is. I also have done field ac work that in involved component changes with out the aid of vacuum pump. I used the intake manifold vacuum to get at least a partial vacuum. And non compressibles will not destroy a system they just affect the its ability to cool what it means is you have air bubbles taking up space where refrigerants should be. A perfect vacuum at sea level is 30 inches mercury I use a a lab grade vacuum pump and can get to 29.7 inches of vacuum. and I have never sucked in or collasped anything and at that level of vacuum there is about is close to nothing in the system as can be.

May 26, 2007 | 04:56 PM

#17

pgw85706

Thread Starter

Elder User

Joined: Nov 2006

Posts: 696

Likes: 0

From: Lynchburg, VA

Thanks to everyone for the inputs and discussions.

Update: I purchased a can of the refill refrigerant at Autozone....Interdynamics brand. With the HVAC set to AC MAX, I ran the truck injecting some of the refrigerant. I followed the instructions on the can and frequently attempted to inject refrigerant over a period of about 15 minutes keeping the truck running. I made sure the can was warm. I repeated the process a second day. There has been no change on the temperature of the air coming from the dash vents. Judging by the weight of the can, very little went in.

All the while, I noticed the compressor would engage then shut off. It cycles on and off about every 4-5 seconds and is very similar to the other member's Scott00 thread today on this topic. I am monitoring his thread to see if anything new there arises.

As always, any feedback or suggestions are appreciated. Have a fun and safe holiday weekend all.

Pat

May 26, 2007 | 05:28 PM

#18

Rockledge

Post Fiend

Joined: Jan 2003

Posts: 9,748

Likes: 16

From: Connecticut

Not all that uncommon. Sometimes it can be difficult to get the flow going because the compressor won't run with a low charge. That's where jumping the cycle switch comes in.

May 27, 2007 | 04:32 AM

#19

pgw85706

Thread Starter

Elder User

Joined: Nov 2006

Posts: 696

Likes: 0

From: Lynchburg, VA

Quote:

Originally Posted by Rockledge

Not all that uncommon. Sometimes it can be difficult to get the flow going because the compressor won't run with a low charge. That's where jumping the cycle switch comes in.

Rockledge, this is the second time you've mentioned jumpering the "cycling switch". This is the only suggestion I did not act on because I do not know where this switch is located. Can you provide further details on the cycling switch.....where it is located, what it looks like, are there only the 2 pins in the connector.... Thank you. Pat

Never mind....the switch is located at #1 in the schematic. I should have looked more closely because as always your information is very complete. I will repeat the task today being sure to jumper the switch. Thanks.

Last edited by pgw85706; May 27, 2007 at 04:49 AM.

Jun 4, 2007 | 06:56 PM

#20

pgw85706

Thread Starter

Elder User

Joined: Nov 2006

Posts: 696

Likes: 0

From: Lynchburg, VA

Update #2: After jumpering the cycling switch, I injected a second can of R134a. I had not driven the truck much (both our sons are in from school and the truck serves as the 4th vehicle) since I did this to really know if the AC was working properly. Plus I wanted to wait to confirm there was no leak and the charge was holding. Well today I got caught in a heavy, hot rainstorm and I turned on the defroster and.....bingo - nice, cool dry air came out of the vents and all the condensation on the windows immediately was gone. So I believe the refill worked fine but I will monitor. The trick was Rockledge's suggestion to jumper the cycling switch....I remember when I did this, you could hear the R134a getting sucked into the system.

Pat

Last edited by pgw85706; Jun 4, 2007 at 06:58 PM.

Jun 5, 2007 | 11:23 AM

#21

blackie96

Elder User

Joined: Mar 2007

Posts: 727

Likes: 0

From: Mount Airy, NC

Not to but in or anything, but I'm having the same problem, and we tried to recharge with the same result. Didn't know about the cycling switch. What do you guys mean by "jumpering"?

Jun 5, 2007 | 01:13 PM

#22

Rockledge

Post Fiend

Joined: Jan 2003

Posts: 9,748

Likes: 16

From: Connecticut

Quote:

Originally Posted by blackie96

Not to but in or anything, but I'm having the same problem, and we tried to recharge with the same result. Didn't know about the cycling switch. What do you guys mean by "jumpering"?

"Jumpering" or "jumping" means connecting the two pins in the harness connector using something conductive, such as a wire. You do this in order to complete the circuit. Same thing as closing the switch. When that happens, the compressor engages.

Take the ends of a small piece of wire and plug each end into the holes you see on the cycling switch harness connector.