The dry air filters were saved by Matt from BaBar, residing inside the curtained area of B84 EPP lab. House compressed air are filtered to let out through the flow meter with a max flow of 20 ft³/min. A 80ft long hard polypropylene tubing with 1/4" OD (McMaster-Carr #9349T2) takes the drive air down to the ATLAS benches. The dry air supply tube terminates at a diverting valve (no shutoff) (McMaster #45165K42) on the bench to allow the switching of the dry air between a test port and the through path to module cooling unit. The through path continues with the same type of tube to transition to the 30cm long dry air tube into the module cooling unit which is an ID/OD=1.8mm/3.0mm blue tube from CERN shipment (same as the vacuum tube). This transition uses a similar strategy as the vacuum tubes, with a pair of Aluminum low-pressure 1/4 NPT adaptor to barbed tube fitting: 1/4" barb - male NPT (with O-ring) on supply side (McMaster-Carr #5058K441); 1/16" barb and female NPT on module side (McMaster-Carr #5058K641).

The initial turn on of dry air should let run for a few hours with the outlet going to the test port using the diverting valve. Check flow and humidity at the test port before flowing into the module cooling unit. Once on for operation, the dry air flow should not be turned off. From an off state, the restart should always have the few hours of initial flush first. During operations, if the dry air needs to be off at the module cooling unit, use the diverting valve to temporarily directing the air to the test port.