The Hydromaster is a controller which senses level, pressure, and maintains a air balance of a hydropneumatic tank and controls one or more pumps. The Hydromaster has adjustable pressure sensors for pump control and add air sensing. The controller provides solid state probe level sensing and a Tank Probe Assembly for front mounting to the hydropneumatic tank. The Hydromaster control can be furnished for add air or a combination add air, air vent operation. H1-242-1 Hydromaster is a one pump controller, Form B, with 4 ½" pressure gauge visible through the front door. Nema 1 enclosure for indoor wall mounting. R-B Probe Assembly for front mounting to the hydropneumatic tank. Pump alternation for 2 of 3 pumps is also available. Air to the hydropneumatic tank can be supplied directly from an air compressor or by controlling a solenoid valve in the air line.