Ducman82

this guy? number 17?

i do have my fan control set up to power up to half speed ish, when the AC is on, not counting the aux fan i just re added. but i like that other switch idea.... could have saved me some fab time.. LOL. i should be headed to gregs and marks tomorrow, so i can rummage around 928intl and see what i can find.

dr bob

Jake--

Get the connector too.

And run the fans on high when the AC is on especially with R134a conversions. You may want to shop around for a combo pressure switch with a lower overpressure cutoff setting too. More than 350 psig gets to be too much in a hurry.

Ducman82

from what i can tell the R12 nipples on the dryer pipe/tree are 7/16-20..... does anyone know what the thread on the pressure switch is... i think its m10x1.0

WallyP

I think that the best system is:
- Add a good relay to operate the compressor clutch, triggered by the original black wire;
- Add a second relay, triggered by the first one, to operate the fan or fans on high.

This can extend the life of the under-sized relay in the HVAC head unit, and gives better AC performance and longer system life by adding condenser cooling.

Ducman82

the cool thing is i have manual HVAC i my car, so it has a nice big relay on the CE panel. but not a bad idea on the fan.

right now I'm searching for a trinary switch with a fitting that will work on the Drier pipe/stock fittings.

Ducman82

found one with 30psi low pressure cut off, fan on at 195psi, and high cut off of 384.... think thats to low for the hight cut off?

Alan

R134a?

Alan

Ducman82

yup

found this one, might be better
MT0381
http://fs1.omega-usa.com/SantechCatalog/#?page=124

Ducman82

compressor has been cycling off and on at idle. I'm wondering if 384 is to low for a high cut off?

griffiths

When cycling off:

What is:
1) Ambient outside air temp?
2) High side pressure?

Ducman82

ya, need to get me a gauge set.... i gave robs back. its 90 outside! that much i know .

Speedtoys

The high switch is 30 bar. 435psi.

Soo....I think thats within variance of what it could be accurate to.

Speedtoys

Stock switch is 2psi on the low side.