Hot Water Circulation

[martynwhiteley]

I've still to recommission my DHW system following my engine swap, but must get round to it soon.

The problem is that one is supposed to fit a circulation pump into the system to transfer the closed cooling liquid through the calorifier (according to Mercruiser).

The old installation was just 'gravity fed' from one of the BMW heat exchangers, and seemed to work fine.

It looks like I'm going to have to buy a pump, but which one/type?

Anyone else fitted a pump to their hot feed circuit to the calorifier?

(And BTW what's happened to the very knowledgeable and helpful 'Spannerman' ? )



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[sfh]

Just had a look at your pictures, looks scary, how did you fill the holes where the drives were fitted

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[Col]

Sounds like a con to me. Your water pump will do that, same as in a car. but instead of using the water to run the heater, yours would heat the water.

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[ballena]

We have a Volvo V8, it runs the water heater directly from the main circulating pump, so no problems.

<hr width=100% size=1>V8's rule!

 

[martynwhiteley]

Yes the holes were a bit bigger than I expected!

Fortunately the 'new' hole for the Alpha drive was comparitively small, otherwise they would have all linked up!

I had two 6mm stainless steel plates profiled. One to fit the outside of the whole transom board area, and one the inside. The outer one was bonded to the hull with a two pack flexible epoxy, and both plates 'joined together' by 16 counter sunk bolts picking up the redundant holes from the old BMW drives. I filled the 'void' created by the old holes with Isopon P40, having first sealed all bare timber surfaces.

The outer plate was then coated with a 2 pack epoxy paint, after sanding the surface to help adhesion, plus antifouling where appropriate.

I did end up with a very slight weep through one bolt hole, prob because I tried to tighten it after the boat was in the water. The leak has since ceased due to the build up of crud on the antifouling no doubt.

Not a traditional method, but it seems to work............


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