Ondemand hot water heater running off the engine cooling
system? Now a water heater running off an engine cooling
system Ive heard of...I'm not all knowing tho.
But the plumbing
mod you state wouldn't be very efficient. you'd do better running the fresh water off the supply side of the heater through the on deck
coils and back to the hot water heater. adding the pump and circulating it through the heater. You would have the heaters water volume and the volume of water in the coils on deck
, increasing the amount of hot water and the insulation of the water heater would keep it hot longer into the night if you turned off the circ. pump after sunset. Why try to transfer the heat twice?
You would also be eliminating the chance of getting an air block in the engine cooling system, switching the valves back and forth, and over heating
the engine at an inopportune time.