Winterize water heater with engine heat exchanger

[farmer.leo]

I've got an electric water heater that is supplemented by heat from the engine heat's exchanger. My plan is to drain all the cold and hot water domestic systems, and then blow out water in the lines with a moderate air compressor. The water heater will be emptied too of course, and I'm told a bit of vodka in the tank is good.

I'm wondering what needs to be done with the heating hoses coming to and from the engine to the water heater. I'm not sure if this is "fresh" water system (anti-freeze) or raw water. I'm inclined to think it's the Engine Heat Exchanger 's "fresh water". If this is the case, then I'm wondering if I'd need to disconnect and bypass this connection to the water heater.
Do I need to disconnect the two tubes from the heater and connect them to each other with a double ended hose barb? Or is it OK to leave them connected to the heater.

Don't know if using the engine makes a difference on how to winterize the hot water domestic system. I plan on running the engine during the winter, either for a sail on nice days, or at least once every month or two to keep things lubed.

 

[Heckler]

I've got an electric water heater that is supplemented by heat from the engine heat's exchanger. My plan is to drain all the cold and hot water domestic systems, and then blow out water in the lines with a moderate air compressor. The water heater will be emptied too of course, and I'm told a bit of vodka in the tank is good.

I'm wondering what needs to be done with the heating hoses coming to and from the engine to the water heater. I'm not sure if this is "fresh" water system (anti-freeze) or raw water. I'm inclined to think it's the Engine Heat Exchanger 's "fresh water". If this is the case, then I'm wondering if I'd need to disconnect and bypass this connection to the water heater.
Do I need to disconnect the two tubes from the heater and connect them to each other with a double ended hose barb? Or is it OK to leave them connected to the heater.

Don't know if using the engine makes a difference on how to winterize the hot water domestic system. I plan on running the engine during the winter, either for a sail on nice days, or at least once every month or two to keep things lubed.

The pipes to and from the calorifier to the engine and the fresh water system on the engine should be full of an antifreeze solution. So why are you wanting to drain it?
Stu

 

[farmer.leo]

The pipes to and from the calorifier to the engine and the fresh water system on the engine should be full of an antifreeze solution. So why are you wanting to drain it?
Stu

That's what I thought but wasn't sure. The potable water system will be drained.

Just verifying that if hot anti-freeze passes through the closed loop of the empty water heater it shouldn't cause any problems.

 

[vyv_cox]

I assume you are talking about a calorifier? A closed tank heated either by an immersion heater or by a coil circulating coolant? Using the engine without domestic water in the calorifier will do it no harm at all. Otherwise, as Stu says, if it's an indirectly cooled engine there is no need to drain the coil or hoses.

If you are not using the boat, leave the engine alone. Nothing positive is achieved by running it and much that is negative.

 

[david_bagshaw]

no need to vodka the water side either, just drain it and the little left, can only produce a frozen puddle.

we have had both types, the small domestic type with a coil, 20+years and the horizontal heated outer skin 20 years, only ever drained the fresh, left the engine side alone with antifreeze.

The only special thing we do is tape the breaker for the immersion heater to make certain it doent get turned on accidently while empty.

ps A wet vac is the most useful tool when winterising the plumbing