Dictys

I just refurbished my a/c system, new compressor, new condenser, new expansion valves and full convert over to new gas style. Complete flush of every part of the system etc etc.

The heater core has been bypassed and the fresh air flap shut by supplying permanent vacuum.

Using a IR gun on the center vent I am getting -38.2c, fan on 1, car at idle with out side temp 40c in the shade.

I think this is too cold? Could there be a problem with the freeze switch not cycling the compresser? How do I test?

Thanks in advance.

j.kenzie@sbcglobal.net

Hello,
Yes -40 is too cold. IR guns are not the best way to measure; a digital meat thermometer is better. It implies your low side pressures are too low either due to leakage or obstructed expansion valve. Also, as you said, your freeze switch should be shutting off compressor at these temps. I would check system pressures and pull and test the freeze switch or just replace it since they are not expensive. I suspect you may have water vapor or other debris in system which is partially blocking the expansion valve.
Good luck,
Dave

depami

Who needs A/C anyway?



Good luck, stay cool.

yak 944s

I am going to tackle my AC system next and convert over to R134a.. R-12 is not available anymore in Canada.. :-(
So would you have a parts list that you compiled when doing this? I am especially interested in the parts numbers for all of the o-rings in the system.

TIA

Dictys

The compressor and dryer where direct replacements supplied by roger.

Hoses, condenser were custom made for me. The condenser is a replica of the existing condenser however with more capacity, unfortunately it is not parallel flow condenser.

The AC shop supplied the o rings and the new expansion valve ( they did not use the one roger supplied).

The only part not changed was the in dash evaporator, this was flushed multiple times seperately by the AC guys before install.

The heater valve was left in however we noticed that the air was about 6c at the vent, even though the heater valve was fine, the air was being heated by water in the return line.

We then put in a U connection at where the water enters the heater core to the return line so no hot water can enter to the heater core either from heater valve direction or from the return line.

The recric air diverter flap vacuum actuator was then connected to directly to the main vacuum system thereby forcing the flap shut.

The air temp was measure again after idle for 10 minutes or so and we got -38.2 c.

SteveG

Minus 38 centigrade, really.

MainePorsche

That's nearly -36 deg F.

SteveG

Yes. Trivia extra credit. That's near the (only) point at which C and F coincide -40.

Dictys

Yes, MINUS 38.2c that is correct according to the IR gun pointed in the center vent.

dprantl

An infrared thermometer is not so good at accurately measuring the temperature of flowing air. Try using a thermometer with a metal probe instead.

Dan
'91 928GT S/C 475hp/460lb.ft

Herman K

Get one of these > http://www.ikea.com/us/en/catalog/products/80100406/

If you don't have an Ikea nearby I can mail you one (PM mailing address)

Dictys

I also it found hard to believe, there is indeed an Ikea here Herman so I'll pop along tomorrow and pick one up and see what that reads. I suspect as you guys do it will be a lot higher. Thanks.

jeff spahn

When you do end up doing your conversion you need to remember to get some stuff called Nylog in the blue bottle. It is a miscible (it mixes with the R-143 with no issues) goo that you put on the o rings. It will help ensure your system stays sealed. Don't forget this.

dr bob

Dictys--

Curious what replacement gas was installed in your system.

TIA!

Dictys

R134a was installed. That why the AC shop wouldn't use the expansion valve I had sourced from Roger.