Where is the low pressure valve for refilling AC gas? There are two silvery AC pipes, the larger AC pipe is for low pressure and the smaller pipe is for high pressure, and I should refill via low pressure valve. They both have each a gas valve port with a black cap which I think means R134A gas (grey cap means R134YF I guess).
On the low pressure valve is a coca cola can sized cylinder called Dryer Filter, is AC gas refilled at the black cap valve on top of this cylinder? Does engine radiator fan need to be in working condition in order for AC compressor to start to suck in the AC gas (I think not from what I read)?
I marked it in the attached picture.
Some people write to not use AC gas with oil or sealant because it can clog the AC refill machine of a car mechanic shop when it vacuumes the AC. So I use only gas.
Update: I tried to fill outdoors in 10 Celsius the AC but the canister cooled itself down so much that it lost pressure. On bottle it indicates ambient temperature should be at least 18 Celsius.
