I'm pressure testing some PEX before I close in the walls. I pumped in 80psi of air around noon yesterday and it was about 60 degrees F. Was a solid 80psi from when i filled to to 11pm (11 hours). The pressure in the lines went from 80psi to 74psi over night. It got down to about 50 Degrees F.
Could I loose 4psi to the air getting cold? I Have there is probably 50' of 3/4" PEX and 20' of 1/2" PEX in the closed system.