That Raritan discussion of engine coolant is not very advisable. You do not want to put a valve in a system that shuts off the coolant from the engine to the engine heat exchanger
. What is better is to have ball valves in the supply and return hoses of the water heater.
- - The supply hose to the water heater comes off the outlet of the engine coolant water pump. Perkins actually have an additional "plug" in the outlet of the water pump for attaching the line to the water heater. The return line from the water heater can be attached to another provided hose plug
in the cylinder head
- - In essence you have two heat exchangers: first the normal one and secondly the water heater. Opening the water heater coolant line ball valves allows the hot coolant from the engine cooling water
pump to pressurize and send hot engine coolant to the hot water heater which then returns to the engine.
- - Should a hot water heater hose leak or burst you can shut both ball valves and maintain the integrity of the original heat exchanger system on the engine. Partially opening or closing the supply line valve to the water heater regulates how much hot coolant is sent to the water heater.
- - Good quality stainless steel
ball valves work great and stay operational better than brass/bronze valves.