Leaking Evap

Dave0176

2 year old system all frozen HO called installer last summer she said he charged it up and she’s good to go, however this year it was out of gas again, she was gonna call him again but someone suggested calling me, I leak checked it and found the leak at schrader valve on the unused TXV port on the suction line in the Evap, upon further inspection there was no schrader valve at all just the plastic cap. I’m assuming the installer forgot to install the valve after brazing (common). Anyway replaced it recharged it good to go.

Dave0176

@ThomasMiller1 are speaking to me or just in general, just wondering because I’m not the HO I’m the contractor who fixed this system??

GBart

Reminds me of one I found long ago on a Liebert unit. Found it low on charge, like almost out and on the evaporator tube sheet I saw a small finger bandage, yeah like a band-aid, peeled that back and found a piece of a plastic lunchbag tied in a knot around a pinhole.........this was in a military computer facility where you'd have to jump through hoops, burn permits, etc and get the halon system turned off, fire watches, fire dept, etc, so I guess that was how they avoided all that?? Epoxy might have been a better option.

Leonard

Reminds me of when I changed out a leaking evaporator in wife's car long ago. Didn't have a long schrader valve tool so just used a short tire one to put valve back in, low side. Leaked ~ 3/4 pound of gas every year..... for years. But R-12 was only < $1/can at Kmart.

Finally noticed bit of pressure when removed plastic cap. Made a long valve tool and found valve was not fully tight. Port was so deep tire tool ran out of length and came off valve before it was tight. Originally seemed to be almost correct torque......

ChrisJ

It's actually surprising how many people (homeowners etc) think it's normal for air conditioners to leak.

If I need gas added......I want to know why.

Leonard

Engineer not AC guy. After I learned by recharged my car I started doing customer car recharges after work. Easy beer money before EPA.

Assumed window AC's would need same , so recharged one and found it didn't help. Eventually figured out they "never" leak. All they need is condenser cleaned of dust that stops air flow so they can't cool off.

Only window AC's that seemed to occasionally leak were GE cheap plastic 5k BTU ones. They used gray hard epoxy to seal aluminum tubing to pump tubing instead of braze. Soap test showed epoxy joint was leaking.

ChrisJ

Leonard said:

Engineer not AC guy. After I learned by recharged my car I started doing customer car recharges after work. Easy beer money.

Assumed window AC's would need same , so recharged one and found it didn't help. Eventually discovered they "never" leak. All they need is the condensor cleaned of dust that stops the air flow so they can't cool off.

Car systems are open systems, the compressor has a shaft seal and the system has hoses, O rings etc.

Window units, refrigerators, central air split systems etc are all hermetically sealed, no seals to leak etc.

That said, modern automotive air conditioners barely seep. Older R-12 systems 1 ounce per year was normal even whenj they were new. Since the R-134A systems got going in 93-94, I'd expect much less than that. The modern systems are surprisingly tight for open systems.

On automotive systems I'd look for oil at joints.....under the compressor etc. Also make sure the plastic caps on the valves are tight as they act as a secondary seal for the Schrader valves.

Leonard

Building units are nice, hermetic copper. Cars have hoses, guess metal lines would fatigue from engine movement and micro-crack.

On old cars ( ~ 70's) outer layers of hoses had laser pinholes so gas diffusing out would be released instead of ballooning the outer layer.

Had a 20 year old Chevy, (R-12). Hose on low side dried out and got loose, could turn it on pump tubing. Too old for new hose, so cutting off 1/2 of crimped aluminum clamp, and installed screw type clamp.

GF's 96 chevy caprice leaks 134a. Other than your list, what parts typically go bad on that one?

Years before that her 91 caprice leaked, they kept recharging it till new car warentee ended. After she told me this I added UV dye .... WHOLE evaporator glowed, end to end . I replaced it.

ChrisJ

Leonard said:

Building units are nice, hermetic copper. Cars have hoses, guess metal lines would fatigue from engine movement and micro-crack.

On old cars ( ~ 70's) outer layers of hoses had laser pinholes so gas diffusing out would be released instead of ballooning the outer layer.

Had a 20 year old Chevy, (R-12). Hose on low side dried out and got loose, could turn it on pump tubing. Too old for new hose, so cutting off 1/2 of crimped aluminum clamp, and installed screw type clamp.

GF's 96 chevy caprice leaks 134a. Other than your list, what parts typically go bad on that one?

Years before that her 91 caprice leaked, they kept recharging it till new car warentee ended. After she told me this I added UV dye .... WHOLE evaporator glowed, end to end . I replaced it.

Most of the times you'll see oil leaking from the compressor shaft. Next would be connections, like to the compressor etc. Then evaporator, or condenser.

On a 96 Caprice, I'd check the compressor, especially if it's the one I'm thinking it is. They had issues leaking at a seam in the compressor housing. You'll typically find the bottom of the compressor soaked in oil.

Leonard

I'll check compressor seam and clutch area first. Took couple days to replace evaporator on her similar 91. Had to take seats , part of carpet, and dash out to remove air handler.

96 , 4.6L V8 .... believe compressor on that one is low in the engine, passenger side.

Dave0176

Most modern auto compressors have multiple body O Rings, after some years of use the aluminum seems build up corrosion and a lot of times they leak at that point. As @ChrisJ was referring too, the worst offender seems to be the GM Harrison HT-6 compressor installed in many large GM cars and trucks in the 90s, I had one in my 99 Tahoe, that also was a leaker. I bought a reseal kit for it, took it all apart cleaned it up new ORings and it was nice and tight. Chinese copy’s of these compressors are junk and that seems to be all that sold in the big box auto stores. Sanden and Seltec a make good tight compressors and they make direct replacements for the HT-6, however a $20 reseal kit is all that’s needed, and the proper tools of course.

unclejohn

Lennox does not put a schrader valve on there evaps. Thats where the TEV connects IF you use one. It would be nice if they did put them in and you had to remove them to install the TEV. But 1/1000 of 1 cent is a lot these days it seems.