Regal LS4C Owner's Manual page 79

Pump-Out Fittings-Chemical Head
The chemical head features a pump-out fitting
option. If installed there is a waste pump-out fitting
on the deck designated with the word "waste" and
the international symbol for waste.
You need to monitor the waste tank level gauge
and when full contact the marina or designated
business to have the tank pumped out. They will
install an adapter hose into the deck waste fitting
and turn on a vacuum pump which will empty the
waste.
After this operation it is always recommended that
you rinse the waste hose out before screwing in
the waste fitting cap. This helps in reducing odor
and keeps waste debris from sticking to the inside
of the waste hose which in time could build up and
affect the pump-out process.
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