Concepts

When you are pumping out the indoor unit, the valve core is removed and the valve on the big line is shut from the inside (but open to the evacuation port)
Through the whole process - gas is sealed inside the outdoor unit
Evacuation and valve core removal occurs with gas shut off and contained inside the outdoor unit.
Evacuation pumps out the outdoor unit only. Refrigerant gas is shut off and contained inside the outdoor unit.
How do we know if all copper tube connections were made properly when connecting the indoor unit? Key: after pumpout, pressure stays below 500 microns.

Work Doc