2GMF water heater/exchange connection help

[thelilnauti]

Hi all,

I'm just looking for a bit of help, advice. We have a new water heater installed which can do both electric and heater exchange connections. We have the electric bit done and I'm now looking to connect it to the heat exchanger. I may be over thinking it but I can't seem to get my head around where or how to connect it. I know the water heater has 2 simple 5/8 in/out connections but where do I connect it to the engine? I've included a photo of my engine (Yanmar 2gmf). Any help would be appreciated, thanks.

 

[kloudie1]

Those two red hoses on the water pump (coolant pump, not sea water pump) should go to the connections for the heat exchanger on the tank..

 

[thelilnauti]

Does it matter which one goes to which on the water heater?

 

[kloudie1]

The one under the thermostat housing is output to the heater, and the other is from heater, back to engine. Check the heater to see if they want ‘em in a specific place.

 

[MikeHoncho]

Put quarter turn valves on the engine side of the hoses.

 

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[Ralph Johnstone]

Feed the engine outlet into the lower connection of the heat exchanger so that all of the air bubbles are blown out of the exchanger. 2GM and 3GM have the same cooling water connections.

 

[ggrizzard]

thelilnauti,
It seems that the team got you the answers you needed BUT...
I have a question.
Have you found the salt water leak that's causing the rust all over your engine?
It could be a leaking stuffing box or PSS seal slinging water all over the engine bay.
I'd get that sorted before you have to spend a "Boat Buck" on engine parts.
It's easy enough at this stage to find and fix the leak, then remove the affected parts, sand and paint before rust eats them up.

 

[kloudie1]

thelilnauti.. If the tank has one connection that is slightly lower, closer to the base than the other, the lower connection would be connected to the outlet from the engine, the one at the thermostat housing.. That would assure that the air is forced out of the heat exchanger and back to the engine.
Some brands don't have an inlet and outlet marked, in that case, it doesn't make a difference.

 

[jviss]

If your water heater is not at nearly the same level as the engine, if it is higher up, you should install a secondary engine coolant tank at or higher than the heater; put a lower-pressure cap on this tank than on the engine tank (usually the exhaust manifold tank). Fill at the high point.
Here's an article explaining this:
https://stevedmarineconsulting.com/water-heater-primer/