Yeah, that's what I've been thinking of doing when I check the pressure.
The hoses are so long, they've got to be holding a good amount of air.
I'll be testing the pressure in both heating and cooling modes, so the pressures will be different.
Making it very likely that any gas in the hose might be back-fed into the system.
I'll make sure there isn't a lot of air in anything that could possibly into the lines.