Disconnected Vacuum on A/C unit

[nawlins-tim]

Basically for fear of leaks, I want to run my air conditioning WITHOUT a vacuum source hooked up. Does anyone out there what will happen. I suspect I will ony get air comming out of only one area. I can't afford any vacuum leaks since I am running a hot cam as it is. It is just too hot and humid. Maybe after I get things sorted out with my a/c I will buy a new vacuum switch. I just got a new blower, and relay and will be charging it up tomorrow. any help would be greatly appreciated.
Oh yeah I have a 1980 ElCamino.

 

[LS6 Tommy]

IDK if the system acts the same with no vacuum source as it does with the switch "off". In other words, you may need to have vacuum just to get the air doors to do anything. If the system does default to the "vent" position, you bring in 100% outside air. Your A/C will not work real well, but it should come out of the "normal" spots.

Tommy

 

[nawlins-tim]

"Outside air"? You mean recircurlate? If that is so , I wouldn't mind. Some has to know for sure. If not I guess I'm gonna be trying it out to see for myself.

 

[LS6 Tommy]

Outside air is exactly what it sounds like. All the air flowing through the ducts comes form outside, so if it's 90* outside the A/C will be trying to cool 90* air all the time instead of having the air get cooler as it recirculates through the system from inside the car. It won't get the car very cool.

Tommy

 

[nawlins-tim]

I tryed it finally.. it seems to default to the defrost and floor positions. I had to jump(by-pass) that pressure switch that is connected to the dryer. You know that aluminum piece on the pass side near the fan and other a/c stuff. I have to look into it's availability.

 

[LS6 Tommy]

The switch may not be bad. Do you have refrigeration gauges for your refrigerant type? If so, with the A/C running that switch shouldn't open until you get down to around 20 Psig on the suction side. If it's opening at a higher pressure than that or it doesn't close at all, it's a bad switch. if it's not, you're low on refrigerant.

Tommy

 

[nawlins-tim]

No gauges. And i don't know if it is safe to just add a can of freon. Anyone know how to check that pressure switch.