calorifier location Moody 333?

[willtaylor]

Our gas water heater has died during the winter. Thta's probably not such a bad thing as there was doubt about venting. However, hot water is nice.

I am attracted by the idea of a calorifier heated by the engine, and since we often have to use the motor to get away from and back to our Tamar mooring there should be a sufficient supply of 'free' heat to justify such an installation.

The problem is how big is big enough and more importantly, where to put it?

If there is anyopne out there with experience, opinions, radical ideas let me know.

Enjoy the new season now the weather is back to normal.

Regards,

Will Taylor

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[timchapman]

If you have a yacht don't think you are going to have hot water after motoring for 10 minutes. The engine needs to be run under load at cruising speed for 1/2 hour or more to get hot water. The smaller your boiler the quicker it heats obviously.

Between 5 and 10 gallons is good. You need to try and locate it LOWER than the heat exchanger on the engine for best efficiency. This can be a challenge. Once you've got it though you'll like it, particularly with a 240V immersion heater added.

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[mickp]

I am also looking to fit a calorifier to Moody 33 mk1, thought about cockpit locker as a good place anyone got a better ideas

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[vyv_cox]

I don't know anything about the Moody but I have quite a bit of experience with both seaawater and fresh water heated calorifiers. Details depend on what you have. Easiest is a fresh water system, you only need to arrange for a supply and return of coolant via the manufacturer's fittings. It is easier to fill the calorifier if it is sited lower than the fill point but it is possible to do it when it is higher. Using the standard circulation pump you should get away with a lateral distance of a couple of metres without problems. It's important to ensure that circulation goes the correct way, otherwise the thermosiphon will cancel out the pump flow.

Raw water cooled systems can work well but this depends very much on the engine fitted. The Bukh system is good but needs a separate circulation pump. Yanmar and Volvo are less good, mainly relying on the water being discharged from engine to exhaust. In this case you need to ensure as far as possible that the supply does not contain the bypass water, which lowers the temperature. With a circulation pump you can site the calorifier some distance away but doing this without such a pump would put more back-pressure on the raw water pump. In this case I would site the calorifier as close as possible to the engine.

I find a 20 - 25 litre capacity calorifier to be ample for two of us. Coolant temperature is about 60C with raw water and 80 with fresh. This clearly has an influence on water temperature. Water from my Bukh system used to be almost too hot to touch in 20 minutes. I now have a fresh-water cooled Yanmar that heats very rapidly. I guess that raw-water cooled Volvo would take more like 30 minutes.



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[willtaylor]

Thanks Tim

That's just the point. If we are only out for the day we very often use the motor for about half an hour, sometimes more if there's a head wind and/or an adverse tide. Moreover, until we install our planned solar panel / wind genny/ Adverc set up, there may be some point in runnning the engine for some time during longer coastal or cross-Channel voyages.

I think the port cockpit locker could work well, especially with the unexpected intelligence that the can should be mounted below the heat exchanger. Can you explain why?

Will Taylor

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[Trevethan]

I have just fitted a 12 gallon model from a ditchcrawler builder on my Sole Bay ketch. The engine is a Lister HR4W (fresh water cooled)

Basic rules are: fit calorifier below top of header tank,
Site it as close as posible to the engine,
Get one with a 240 volt immerssion coil (but make sure it uses around 1000 watts or .it will pop the breaker on the pontoon.
Get one that id s properly insuilated.

Ours heats up using the immerssion in about 20 mins, and just 15 mins of engine, even at idle brigs it to ausuable temperature... though not as hot as it can get.

It stays warm for a couple of days.

It's a good idea to fit a non return valve to the cold side of the calorifier to stop warm water working back to your tanks, while on the hot side a blender system will inject some cold water to the hot supply making it go further and reduce the risk of scalding if you try and wash your hands after thrashing the engine fior a couiple of hours.

Good luck!

regards,

Nick

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[aph]

I found it impossible to site the calorifier on a Moody 40 anywhere handy below the header tank. Ended up putting it in a wardrobe locker in the aft cabin about 3.5 meters from engine. I put a blank radiator cap on the heat exchanger and installed an expansion tank 12" above. (like a car) to give a head on the system and expell air. Thorneycroft T108 with Bowman heat exchanger.

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[fiddle]

I have a Moody 333. Came complete with a calorifier. The unit is fitted under the bed in the aft cabin, in the larger forward space. Its probably on a level with the two storage tanks which are under the saloon seats, but the pressureised system obviates any problems. It doesnt take long to heat up sufficiently but its not 10 min. more like 30 min.

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