Abstract: A filter pump cover according to the invention comprises a filter cap, an air purge valve, and a filter cap retainer. An air purge valve according to the invention is comprised of a valve cap, a screw-threaded portion, and a valve stem having one or more outward-facing inverse hooks at the bottom. The inverse hooks are located at the bottom of the air purge valve stem and hook onto the bottom lip of the hollow central portion of the filter cap retainer to prevent complete removal of the valve stem from the filter cap retainer. The valve screw-threaded portion is interrupted by a valve opening slot on one side that permits the release of air from the pump when the valve is opened. The hollow part of the filter cap retainer mates with and holds the air purge valve by means of the screw threads when the valve is closed.