Applications include adjusting appliance regulators, setting delivery pressures, leakage "shut-in" tests, regulator adjustments for pressure and lock-up tests, tests for leaks in low-pressure gas systems , isolate difficult pressure problems on natural gas and propane systems, test pressure switch operation on a 2-stage gas furnace in both positive and negative pressures, static pressures in air ducts for air balancing, and checking air filters by measuring pressure drop