DIY low side AC recharge
#1
DIY low side AC recharge
Hi, I accidentally released a small unknown amount of refrigerant after which my 2001 3500 AC seemed to still cool at about the same level as before and remained that way for the last year until the current heat wave during which it still cools but not enough. I'm sure I used the 18 oz recharge kit properly emptying the canister and the AC was definitely cooling better.
The problem is that the initial pressure reading on the kit was 35 psi and so was the ending pressure. A different gauge after recharge also indicated 35 psi. At ambient temp above 90 I was shooting for 45 psi. I'm sure my readings were correct so how could I start at 35 psi, empty 18 oz's, get better cooling and end at same 35 psi? System is not leaking holding at 35 psi for weeks. Although improved it seems I used to get a little better cooling but am afraid to add more refrigerant until I understand why pressure remains at 35 psi- I don't want to overcharge the system. Thanks for any info.
The problem is that the initial pressure reading on the kit was 35 psi and so was the ending pressure. A different gauge after recharge also indicated 35 psi. At ambient temp above 90 I was shooting for 45 psi. I'm sure my readings were correct so how could I start at 35 psi, empty 18 oz's, get better cooling and end at same 35 psi? System is not leaking holding at 35 psi for weeks. Although improved it seems I used to get a little better cooling but am afraid to add more refrigerant until I understand why pressure remains at 35 psi- I don't want to overcharge the system. Thanks for any info.
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#4
You need a real set of gauges to see what the high side psi is or was. The charge in small a/c units is critical.You added 18 oz. of refrigerant to and saw no change in psi. How did you accidentally release part of the charge.Maybe you need to evacuate the system and weigh in the correct charge. I would go another a/c forum for info. Pressure readings help the tech the determine superheat and subcooling. It's a crap shoot that is needed to determine if the system is operating correctly
#5
You need a real set of gauges to see what the high side psi is or was. The charge in small a/c units is critical.You added 18 oz. of refrigerant to and saw no change in psi. How did you accidentally release part of the charge.Maybe you need to evacuate the system and weigh in the correct charge. I would go another a/c forum for info. Pressure readings help the tech the determine superheat and subcooling. It's a crap shoot that is needed to determine if the system is operating correctly
The van was converted to high top medical transport new directly from the factory and an after market rear AC was added and I could find no records of correct weight of refrigerant so pressure and performance seem the only way to go.
From what I recall pre-leak I'm now only slightly less cool but that's still slightly uncomfortable in hot S. Florida. I plan to add a few ounces a day up to a max of another 12 ounces to see if I can get there.
I don't think this is an issue everywhere but chances are where I live if you go into an AC shop for a top off charge your coming out with no cooling at all and AC problems you didn't have before you went into the shop. I'm not ragging here that's just how dog eat dog it is here.
#6
The line probably has small slow leak and has allowed air and moisture to enter the system don't waste your refrigerant on the system till you properly repair the line.The reason it continued to work is that the it's a slow leak. You probably need a new line and evacuated to remove the air and moisture from the system. A rubber sleeve may slow down the leak but you are still pulling in air and moisture which will eventually contaminate your oil and lead to compressor failure. I worked for few A/C companies and know how they work. There are some that prey on the lack of knowledge the customer, It's all about the money. You could purchase the line and replace it yourself. I'm not telling you to discharge refrigerant to atmosphere which is against the law. All refrigerant must be recovered according to EPA regulations. This is my disclaimer. You may be able to rent a vacuum pump to remove the non condensables and add the refrigerant yourself.
Last edited by ramvan61; 08-02-2018 at 03:34 PM. Reason: spelling