How much refrigerant to charge AC?

[Gray035]

I've completed an install of a new (to me) AC system on my truck, but I don't know how much refrigerant is supposed to go into the system. And since its a system I put together, there's no manual or anything to look at. Everything is new, and I'm using a Sanden style compressor.

So can anyone tell me how much refrigerant I should expect to use? Should I go by trial and error using vent temp?

Need help!!

[sargentrs]

Around 28 oz I think. At least that's what Google says.

[1972hiboy]

which a/c system are you using? new aftermarket or an old system?

[mkoecher]

I have a '76 that I converted to R134a. I put around 1.8 lbs in. It works well. I would maybe try for 2 lbs if I were to do it again though.

[Gray035]

The system has a new 508 syle Sanden compressor coupled with an old dealer add on evaporator unit. The condenser is a universal aftermarket one.

[1972hiboy]

I would expect somewhere in the 1.5lb to 2 range. Do you have manifold gauges? what freon are you planning on running?

[Gray035]

It's a dealer add on unit, but with a new Sanden compressor and new everything else. I put in about 26 oz and it's pretty cool coming out of the evaporator, but I think that I might add a little more.

[Gray035]

Oh, and I'm using 134A.