I've not seen the installation instructions yet, but I gather that the gene ral idea with this sort of system is that you purge the air and moisture fr om the indoor unit by venting some of the R410a from the pre-charged outd oor condenser unit.
Now, being a bit of a perfectionist at times, I have started to research th e Pros /Cons and moral issues involved here. I might install a second one of these units at some point and I am concerned about the longevity/ effici ency and effectiveness of my AC systems !
As I understand it so far, I would just need to get a vacuum pump and a man ifold gauge set, Then connect the pump to the suction side on the condenser unit via the low side gauge and let the pressure fall to 0 psi over 15 min s or so. Doing this means that any water in the lines or wall unit will boi l off.
So then you close the valve on the gauge and check that the vacuum holds. N ext you can crack the high ( liquid ?) valve on the compressor and close it again when the gauge reads 100 psi. or so. This means I will be able to ch eck for leaks under a vacuum and also after I've released the refrigerant .
Assuming no leaks ( soapy water to boot ) then what ? I fully open both val ves on the compressor ?
Do I need to do any thing else before removing the hose from the Gas side s ervice port ?
I don't mind forking out for the gear to do the job properly, can always tr y to sell it on ebay !