Yet another air conditioning thread!

[gadget73]

the low pressure side is what you charge it with, the high pressure side is mostly used to diagnose the system. You can tell if the compressor is weak or if there is a restriction or insufficient airflow across the condenser with the pressure readings. Manifold gauges hook up to both ports and you can watch exactly what the system is doing by watching the needles.

[1987cp]

Interesting. Didn't realize manifolds were actually intended to hook to both ports, as I've tried test-fitting an old R12 manifold someone gave me and it would only fit one port (it had the same connectors on all three hoses). Tried to ask a parts guy about adapters once, but he clammed up when I didn't come forth with reassurance that I was licensed to work with R12.

[Lincolnmania]

yes manifold gauges hook to both ports.......maybe someone visiting this summer can make a video of me doing an ac service

[gadget73]

Interesting. Didn't realize manifolds were actually intended to hook to both ports, as I've tried test-fitting an old R12 manifold someone gave me and it would only fit one port (it had the same connectors on all three hoses). Tried to ask a parts guy about adapters once, but he clammed up when I didn't come forth with reassurance that I was licensed to work with R12.

I seem to remember R12 high and low side fittings being slightly differently sized. I think the high side fitting is larger.

[1987cp]

yes manifold gauges hook to both ports.......maybe someone visiting this summer can make a video of me doing an ac service

Wonder if that had to do with the manifold I was using being intended more for industrial/residential use? I know that a residential system was the last thing it'd been used for.

[gadget73]

if it was for R22, then that would explain it. I seem to recall the R12 high side port being larger than the R22 port. Most home AC systems run/ran R22.

[87gtVIC]

I now have 134 fittings on my car but through the magic of adapters and valves we now use empty134 refrigerant cans filled with r12 and then pump it into my car. The stock cars valve sticks from time to time causing the cheapo adapters valve to stick and give a shower of refrigerant

[gadget73]

Just unscrew the R134 conversion fittings and charge it with normal R12 hoses. Most of the R134 manifold sets I've seen use an adapter on the end to connect to the 134a fitting. Remove that adapter, and you're usually looking at an R12 hose.

[87gtVIC]

Dont have any r12 hoses...anywhere that I can use. This way works and it is free!

[1987cp]

if it was for R22, then that would explain it. I seem to recall the R12 high side port being larger than the R22 port. Most home AC systems run/ran R22.

Oh. Didn't know home systems even ran a different refrigerant! Have they been similarly switched to the new R134 stuff?

[gadget73]

Some, one of the newer units at work uses R401 or something like that. I think the next push is to make R22 unobtanium like R12. Lots and lots of installed R22 equipment though, and people do not replace AC units nearly as often as they replace their cars. On the upside, they also don't leak nearly as much as mobile stuff does.

[1987cp]

Dumb question since it's been eons (well, 11 years) since I had A/C in anything Ford ... how noticable is the compressor drag, normally?


In other news, I got a black light bulb from Menards and went searching for dye tracks, but couldn't find anything in the daylight .... at least from the top side ....

[Piece-it pete]

My 97 GM had some noticeable drag....

My ac work this weekend was full of fail. I bought a cheap air compressor drven vacuum pump at Harbor Freight, ran it for the ten minutes they said, and it still won't take any freon.

I am supposed to be using the port back by the dryer, right?

Pete

[sly]

lopos will have a more noticeable drag due to the lower power rating of the engine. Case in point... my 93 Escort can do 0-60 in about 9 seconds (cold start - about 12 when warm) without the AC on. With it on it takes more like 14 seconds or so (16+ easy when warm). My 88 MGM on the other hand looses about 3 seconds only to 60. The 93 Vic loses maybe 2 seconds. It is noticeable on all of my vehicles. It's a parasite on the engine and anything that is taking power away from moving the car will make itself noticed.

to pull vacuum on an AC system, you need to pull from both the high and low side through a set of gauges (or adapters and a T fitting) This will evacuate the entire system. Once there is a complete vacuum (and it will hold it for an hour without any air getting in) you know the system is good and can proceed with filling the system. The pump should wait until some pressure is obtained from connecting refrigerant bottles to the low side (high pressure in the bottles will expand into the low pressure of the system). Once there's enough in the system for the compressor to run, you can continue filling the system to the rated pressure.

[Piece-it pete]

That pump lies dammit! It says it'll work

Do I have the right cap, or am I going to explode the can in my hand?

Pete