The wheel is direct coupled to the three-throw crankshaft, cast in 1912. Connecting rods link the cranks to three long beams pivoted at the far end. Pump plunger rods attached to the outer free ends travel in substantially straight-line motion.
The pump has three cylinders with a 6½ inch bore and a stroke of 13 inches. The pump is single acting with back to back leather washers. The supply to Petworth used to be via a 3 inch diameter cast iron pipe, a length of 1½ miles and a rise of 178 feet, requiring an operating pressure of at least 75 pounds per square inch. The pump now supplies a fountain outside the visitor centre and is still capable of delivering a "hogs head a minute".