I would like to hook up my jabsco electric head on my B40 to fresh water to both rid my boat of the stink when first Using the head, and to increase use of fresh water so that the tanks are regularly emptied and refilled. Is it as simple as teeing of the fresh water hose from the forward tank on its way to , and before it reaches, the fresh water pump?
Nooooo...and don't even think of doing that! You'd run a huge risk of contaminating your potable water supply with sea water and/or bacteria from the toilet bowl. All toilets designed to use fresh water need PRESSURIZED water and have built in siphon breaks and backflow preventers. And instead of intake pumps, solenoid valves that work kinda like faucets on a sink to allow water to flow into the bowl when you push the flush button and block it when you let go.
There's a very simple and inexpensive --and SAFE--way to supply fresh water to prevent odor caused by sea water left to sit and stagnate in the toilet intake:
Sink drain thru-hulls are below the waterline on almost all sailboats. So re-route the toilet intake hose to tee or wye it into the sink drain line as close to the seacock as possible because the connection must be below waterline to work.
This will allow you to flush normally with sea water. After you’ve closed the sink drain seacock in preparation to close up the boat (you do close all seacocks before leaving the boat to sit??), fill the sink with clean fresh water and flush the toilet. Because the seacock is closed, the toilet will draw the water out of the sink, rinsing the sea water out of the entire system—intake line, pump, channel in the rim of the bowl and the discharge line,(Water poured into the bowl only rinses out the toilet discharge line). If your toilet is electric, be careful not to let it run dry…doing so can burn out the intake impeller. Or you can keep the sink drain seacock closed except when it's needed to drain the sink and flush with fresh water down the sink all the time...your choice.
It may also be necessary to keep the sink plugged except when in use, with a rubber sink plug or by installing a conveniently located shut-off valve in the drain hose. Otherwise the toilet may pull air through the sink when you try to flush, preventing the pump from priming.
--Peggie