I have installed a new Attwood 6 gal heater in my boat. It is equipped with the internal heat exchanger which gets it's heat from the engine. Any suggestions on how to connect it to the 360 Chrysler.

Why? Someone gonna take a shower while you are underway?

Could't have said it better. If the one connection is at the thermostat bypass where does the return go?

If you took the bypass hose off, You would have 2 conections.

Doug,

If I understand you correctly (apologies if I'm off base...):
Your circulating pump is wired so that it will deactivate when the thermostat on the hot water heater "tells" the heating element to kick in.
ie. the circulating coolant from the engines has fallen below 140 deg F and thus can't supply sufficient
heating water thru the loop. So the water heater's element needs to kick in and pick up the slack.
--> This would then mean that a solenoid needs to be in the circulating pump's circuit that would trip/
activate when the current starts at the hot water heater's element - cutting the power to the
pump. This would then prevent heated usable water from transferring its heat to the circulating
pump circuit to be lost in the loop/at the engines. There'd be potentially some heat loss but if the
circulating loop used reinforced marine hose wrapped in insulation a couple of feet from the water
heater, it'd be minimal.

Correct?

Bill

Good move. Nobody wants to get hurt while enjoying boating.

Jeff

Must be winter... wow some really sophisticated complicated ideas.

While I am not setup for engine heated hot water yet. I have had several on sailboats with small diesel engines in the past.

I have found in my experience once the water is hot in the heat it stays hot for a long time up to 6 hrs or longer in the summer. Mine were six gallons and it did not take long to warm it back up. By the time the water was cool it was usually time to top off the house batteries on the hook anyway.


dave

Wow, Bill, you are way out ahead of me. The crewboat install was nowhere near as sophisticated as you are imagining.

The water heater was not wired to AC. A crewboat is normally not inhabited at the dock, and usually has no generator. Folks like hot water under weigh to wash their hands with and so forth, but that's it.

The water heater came with switch and heating coil. I used the switch as-is to run the pump. The pump came on when the water temperature in the heater tank got below its set-point, and went off again when the heater tank was hot. Just as it would with the ac heating element, only getting the heat from the engine block.

This left one problem: when the engine is cold, the pump runs continually since it cannot heat the water. I solved this by wiring the dc for the pump through a breaker on the accessory panel, so that it would normally be turned off when the boat is unattended.

If I had designed this from scratch, I would have tried to eliminate the hot water heater tank completely by installing a coil in the engine block to heat the water directly.

For use on our Marinettes, you point out the need to incorporate the ac heater, and I hadn't given that a lot of thought. But, I think I will do the following:

=> install an open-below-100 temperature switch in the engine, and an open-above-120 switch on the water tank.

=> wire the pump through both switches so that the pump shuts off when the engine is cold, and shuts off again when the tank is hot enough.

=> leave the ac switch (about 140) and heating element as-is, so that they work at the dock.

The ac element should keep the water hot enough to suppress the pump, but who knows until it's tried.

Again, the elegant solution would be to route the water feed for the hot water tank through a coil in the engine so that the heater gets a hot water feed whenever the engine is warm. This might be practical, I need to climb around the engine and look for a place to put it.

Doug

.."either I'm starting to think like Jeff "

My condolences!

Jeff