Raritan Hot Water Heater 8 Gallon

[APWTryfan]

Hi there,

I have an old Raritan with heat exchanger on my 1986 C&C33.

Will running engine if there is no fresh water in tanks/heater cause problems with heater?

The boat is new to me and I just learned that the hot water heater has a heat exchanger that allows heating from engine.

I am assuming that the engine cooling is a closed system and that a damaged hot water tank would not compromise the engine cooling system.

I would think that if there was no water in the heater and if engine was running that heater would expand and rupture. Maybe there is a pressure release valve on these to prevent that problem from happening.

Any insight most appreciated.

Thanks!

Andy

[Calif.Ted]

The engine coolant is only 160 degrees.

[Lepke]

No. The water heater has a loop that normally would be in contact with water. With the tank empty, the loop is heating the air in the tank. And if that was an issue, the tank should have a pressure relief valve.

[APWTryfan]

Thanks for your replies this has and will continue to be a learning experience for me. These forums have been most helpful!

[PDScott]

I have this heater on my CS33. There is a pressure relief valve located near the top of the tank. Just flip if to the center and it will remain open. If the element is burned out you can purchase a new replacement at any hardware store. The original was 1200 watts but a 1250 watt element will work as well. Good luck

[kmacdonald]

It's fine to have engine coolant circulate in the hot water heater with no fresh water in it but don't run the electric heater element with an empty tank. A 750 watt heater element would be fine for a water heater that size. Less chance of overloading shore power or generator with the smaller element.