technician MUST have these equipment
Combination HI / Low pressure gauge manifold
Weight scale
Gas welding/brazing equipment if needed
Vacuum Pump. at least 3 CFM for working on residential split units.
as per the websites, r410 is to be charged as liquid, which means the cylinder must be inverted, the hose connected at the cylinder must be at bottom. this is for the commonly available single nozzle cylinders.
once your system is fully connected, and you are charging a repaired system, prior to any thing, you must connect vaccum pump, and pull a vacuum for 20-30 minutes to ensure that all air / moisture is out of the system.
the manifold allows gas cylinder, vaccum pump and AC to be connected all together. once vaccum holds solid. ie reading on gauge does not change for 20-30 minutes, meaning you have no leaks, you close the vaccum pump valve, and open the gas cylinder valve. the gas cylinder must be resting on a weight scale. you must note the starting weight, (weight of gas required in system is almost always written on the equipment) when the required weight has been subtracted from starting weight of cylinder, you must close the gas valve. disconnect the manifold from AC, and start the equipment.
