Lee enquired: .... how does the thermostat on a older type car work? Would that stop/allow water along a pipe.
An engine thermostat is closed when cold and this allows the coolant to circulate around the engine only. Once the coolant has reached the cut-off temperature, the thermostat opens, allowing the coolant to circulate around the heating system. This enables the engine to reach it's operating temperature faster. I am not sure how you could incorporate this into the system that you have on the boat, though. You can get differing temperature thermostats from a Motor Factors. Sorry I cant be off further help, but I'm sure someone will be along who can, maybe help. Good luck John nb Charlotte Rose [Non-text portions of this message have been removed]
