Tech in chit chat? Vintage air on old C10

[iniviate]

Working on wrapping up the A/C in my 69 C10.

It's all vintage air stuff except for the compressor. It's a brand new factory compressor for an LS motor.

8oz of PAG oil. Vintage air says their compressor comes with new oil already installed, so they don't list a capacity. I went with what the compressor came from, a silverado.

Vintage air says 1.8lbs of freon. It took that very slowly, but eventually got it all in.

Truck blows cold air. 28-30 degrees at the vents.

High side pressure is 175psi. Low side is 10psi with the low pressure switched jumpered out. (when i was charging it) with the low pressure switch in the mix, It cycles the compressor about 12 seconds off and 19 seconds on.

That low side seems way too low. I typically charge the low side to around 30-40psi. But, it gave me a weight so i charged to that... and typically that's spot on.


Should i keep charging it?


TLDR - what's the lowest the low side pressure can be?

 

[fvs]

Low side pressure varies with ambient temperature. 28 to 30 out of the vents is pretty good for vintage air. I’d leave it alone.

 

[yozsi]

Must be cold out. Block off part of the condenser and low side will come up. Txv, variable orifice, or fixed?

 

[iniviate]

Low side pressure varies with ambient temperature. 28 to 30 out of the vents is pretty good for vintage air. I’d leave it alone.

Ok thanks. Just worried about damaging the compressor.

Must be cold out. Block off part of the condenser and low side will come up. Txv, variable orifice, or fixed?

mid 70's here today. I did have a garden hose on the condenser when charging it, but i always do that and i've never had this problem before.

Sounds like it's ok. Maybe this is the coolest i've messed with A/C. It's usually hot as fire here in FL.

edit: IDK what kinda of orifice/expansion it is.