Ac gauges

[tnporsche]

One is comp on other is off.

Freeze 12 92 deg @ 12
' in front of coil

Air in vent 55 deg

Does this look good or does it need more F12?

[mattdavis11]

More. Get the low side to 35-40. The 944 takes 950 grams of R12, or 2.09 lbs. Freeze 12 operates at a higher pressure, so the rule of thumb is 10% less than the rec'd for R12. That puts you at 1.88 lbs of freeze 12 for the system, but that also varies +/-. I'd put in a 1.9 lbs and then look at the gauges and a dash thermometer and dial it in. Keep an eye on the high side, if it gets to 275-300, shut it down and clean the fins on the condensor.

Clarks has the pressures at these numbers. Mine gets colder than this and the pressures are different, but I imagine this is for R12. I'm 134, it's 100 everyday and my vent temps are 37-42 at 2K- 2400 rpm, which is where you should dial it in. I also work on car a/c's everyday, so naturally mine is going to be damned cold.

90 °F ambient

35-40 psi Low

190-225 psi High

44-50 °F Vent

[tnporsche]

What do all the other marks mean?

Ohh Its not on my 944,


I am a true shade tree mech, also notice tree in tree(see photo)

My shed blew away in a March storm,

[mattdavis11]

1 bar is 14.5 psi, 2 is 29 psi, etc, but that's about as much as I know. They are just units of measurement. I see the 134 at the outer, but have no clue as to what it might mean, outside of saying what you can clearly read. To be honest, I never look at the gauges other than inHg psi. I suppose those gauges could adapt to just about anything if you had the right fittings. Your concern is the inside inHg psi #'s though. Bump it up, it's low for any car.

[bazar01]

Originally Posted by tnporsche

What do all the other marks mean?

Ohh Its not on my 944,


I am a true shade tree mech, also notice tree in tree(see photo)

My shed blew away in a March storm,

Just what matt had suggested, just hit around 35 psi at 2000 rpm and wait until the radiator fans are running so you can check and make sure the high side does not go above 300 psi in stop/go traffic.

The other marks are for saturation temps of different refrigerants at saturation pressures for checking superheat and subcooling on a/c systems.