Fitting a Calorifier

[Hermit]

Hello,
Can anyone tell me how (very roughly of course) difficult and expensive (or even possible) it would be to fit a calorifier to a Yanmar 18HP 2 GM? The boat has a pressurised cold system already and space should not be an issue.

I am looking at a boat to buy and it is missing a vital ingredient to get SWMBO onboard more!
Cheers,
Rob

 

[vyv_cox]

Very easily done. This photo shows my installation on a 3GM30 which has essentially the same coolant layout

Hot water is taken from immediately downstream of the circulating pump, piped to the upper connection on the calorifier, returned from the lower connection to the suction side of the pump. All the tappings are present on the engine and you only need to screw in the hose tails.

The rest is quite straightforward. Take cold water via a Y fitting to the water inlet on the calorifier, take hot water out to the tap. You will need the calorifier, tap, hose and a few fittings.

 

[pvb]

Nice & clean!

What a lovely clean engine bay! A credit to you.

 

[Honey]

That looks to me like a 3GM30(F) with indirect cooling - If the engine in the OP is a 2GM then it will be raw water cooled and as a result will pose several problems. If it is raw water then a seperate water pump will be needed and the water will never be hot but will get warm. First we need to know if the engine is a 2GM20 or 2GM20(F).

 

[jerryat]

""If it is raw water then a seperate water pump will be needed and the water will never be hot but will get warm. ""

This seems to be a common misconception among some, but sorry, it is TOTAL rubbish! I, and many others have installed calorifiers with a circulating pump to our raw-water cooled engines and produced water FAR too hot to put your hands in.

I have installed several systems on other boats all with excellent results and have also advised those doing it themselves. Suggest you read the similar thread on this (a couple of weeks ago) where this matter was again discussed.

 

[vyv_cox]

Oops! You seem to be correct about the raw water cooling. I didn't read the post accurately enough and confused the pressurised statement. So disregard my above.

However, I don't agree with your second statement. Raw water cooled engines are perfectly capable of producing piping hot domestic water - the Bukh that my Yanmar replaced being an example of one. I'm not sufficiently aware of the raw water cooled Yanmar layout to advise, but most engines have tappings that will supply hot and return cool water to somewhere. The need for a pump depends entirely on the layout, particularly the horizontal distance involved. However I suggest that a pump will always improve performance. As described in the recent thread, the description of the pump suggests that it is not suitable for seawater. Despite this, my original one was 15 years old when it failed. The replacement was 5 years old when I changed the engine, when it still appeared to be in good condition.

 

[fireball]

We have a Calorifier on our Yanmar 2GM20... raw water cooled ... the water is taken off just above the thermostat and I can't remember where it returns ... the water isn't hot hot, but is certainly warm enough... provided the thermostat is working properly.

 

[freebird1]

Is the tap water in the calorifier (ie the water to be heated for use) gravity fed from your domestic water tank? Does the heat from the water migrate back to the main tank eventually? I would think that passing through the bilge back to the main tank would lose all the heat?