Abstract: A manure pump 2 includes a collection hopper 4 for collecting manure. A housing 20 attached to the collection hopper 4 has a pump cylinder 32 located therein. The discharge end 38 of the pump cylinder 32 has a one-way check valve 40. Housing 20 also includes a return path 60 which connects the discharge end 38 of pump cylinder 32 to collection hopper 4. When check valve 40 is jammed in a partially open position, the return path 60 is opened by removing a valve plate 68. Operation of pump piston 32 will recirculate the manure through the return path 60 back to the collection hopper 4 to clear the jammed check valve 40.