Backup (Forge) Air Compressor This air compressor has been modified - a brass tee was installed between the tank and the check valve to allow it to act as a buffer tank for the forge's power hammer. Model: Central Pneumatic 61489, 2HP  Capacity: 29 gal Pump oil: 11.4oz of SAE 40 is required Factory set points: on at 120PSI, off at 150PSI Manual:  central_pneumatic_61489.pdf