While a slight accumulation of foreign material within shuttle type units will not affect operation, 150 micron filtration is suggested. Any sizable amount of contamination should be removed. Removing the bonnet nut on FS-200, and FS-400 Series units allows the shuttle assembly to be removed for cleaning without disturbing the installation. Sliding keys on the FS-400P are removed, or the bonnet is twisted on the FS-500, for the one-piece bonnet/shuttle to be lifted out of its housing. Consult the factory for replacement parts. Damaged electrical components must be replaced at the factory.