proper way to remove water heater heat exchanger

[nuru05]

We are removing our water heater to make space for an AC because we never use it anyways, and I need to disconnect the lines for the heat exchanger from the engine. Is the proper way just to remove the lines and make a little "U" to feed the outlet back into the engine right at the engine?

[Tin Tin]

What make and model engine do you have?

[barnab]

It is a way to do it, especially if you think you might want the water heater back somewhen. Otherwise the connections for a water heater are retrofits and the "proper way" would be to remove them altogether, which also eliminates the risk of the U springing a leak (but as usual the proper way will be more work).

[nuru05]

Originally Posted by Tin Tin

What make and model engine do you have?

It's a 56 yanmar,

[nuru05]

Originally Posted by barnab

It is a way to do it, especially if you think you might want the water heater back somewhen. Otherwise the connections for a water heater are retrofits and the "proper way" would be to remove them altogether, which also eliminates the risk of the U springing a leak (but as usual the proper way will be more work).

Ok, I might as well do that then. We are away from the boat for a couple months so I haven't actually looked at the connection yet. I didn't realize they were retrofits, it makes sense though.

[Searles]

Having done this both ways ,we normally fit 90 dg on off vlvs to the hoses ,providing they are in good condition ,the take off and return points are easily accessed on these engines,the plus is that’s it’s easy to re fit the hot water tank if you sell the vsl ,often the takeoff nipples in the engine are frozen in not always easily removed to blank off .⚓️⛵️

[Fore and Aft]

Nuru05 I wonder if somewhere on your boat are two bolts with Yanmar silver paint on the heads? I know in our yacht there's 2 Yanmar bolts in one of our parts containers. I kept them years ago just in case I needed to block the hot water heater off in an emergency.
Cheers

[GordMay]

Originally Posted by nuru05

It's a 56 yanmar,

Is your “56 Yanmar” a “4JH5E”, c/w an [optional] Hot Water Kit ? ➥ https://www.yanmar.com/marine/product/engines/4jh5e/

See:
Hot Water [Outlet & Return R3/8] ➥ https://www.yanmar.com/marine/wp-con...2013.04.01.pdf
Parts Catalogue ➥ https://www.mecanique-plaisance-fini...teur/4jh5e.pdf

[Tin Tin]

So if it is a 4JH5E, we are guessing here, then the appropriate solution is to use the plugs and they are in the parts manual noted by Gord at Figure 17 part number 129916-49740. That Figure also shows the HW outlets with and without on/off cocks. If it is not a 4JH5E then what is it?