note: Do not turn the adjustment knob  during the procedure.
Turn the baffle  counterclockwise to remove the filter element .
Soak and clean the filter element , drain nut , the dump valve and the o-ring  in a solution of water and a small quantity of soap. Rinse and dry the parts.Lightly lubricate the o-ring  with a mineral-type grease or oil.
Install the parts in the opposite order they were removed. Tighten the dump valve  and the collar  to prevent leaks, but not enough to damage the o-rings. Connect any hoses that you disconnected.