What Size Calorifier to fit

M

mattnj

Well-Known Member
Joined
26 Jul 2007
Messages
1,362
www.red-data.co.uk
Hi,

Proud new owners of a 1979 Moody 36 CC Mk1....Staring on a refit over the winter, one of the first jobs is install a calorifier so I can wash my hands whilst doing the million other jobs!
Can someone advise me on what size tank to get for a 36, and if there is any good info available on taking a hot water feed off the Thornycroft T90 engine.

The original layout was a gas water heater which is already in the bin.

Thanks
 
The size is largely dependent on how much space you have to fit it. Typically a practical capacity is between 20-30 litres. You need to get measurements of different shapes and sizes to see where you can fit it.
 
There is loads of room, so I should be ok with anything I fancy within reason....I was considering larger size = slow recovery time so what was the "normal" for a 6 berth cruiser?
I see they all have TMV's now so that must help the useable volume.
 
As hinted at above, fit the largest calorifier you have room for.
You can never have too much hot water, and it's heated for free by waste engine heat anyway.
You'll be forever grateful when you have friends aboard, or are staying in one isolated spot for a few days.
 
Trundlebug said:
As hinted at above, fit the largest calorifier you have room for.
You can never have too much hot water, and it's heated for free by waste engine heat anyway.
You'll be forever grateful when you have friends aboard, or are staying in one isolated spot for a few days.
Click to expand...

But it takes longer to heat up? if I went for 100l, it would need hours of running to heat it up, or have I missed something? I think you can have a calorifier that is too large...unless you are motoring loads....must be an idea size. or is the advice "bigger the better!"
 
Just wondering what capacity are your water tanks? Don't forget that your guests might consider the supply to be unlimited and empty your drinking water in a day! 20 litres would be a big chunk out of a refill in my tank and that's with an 80l tank - considered quite a good size on a 28 footer. I considered whether I had the space for a calorifier then realised I liked the idea of limiting each use to a single kettle of water. It becomes particularly significant if you're planning on using a shower...

Rob.
 
mattnj said:
There is loads of room, so I should be ok with anything I fancy within reason....I was considering larger size = slow recovery time so what was the "normal" for a 6 berth cruiser?
I see they all have TMV's now so that must help the useable volume.
Click to expand...

There isn't a "normal", other than it is rare on a boat that size to see much over 40l. You will be surprised how much space it takes, and you presumably have other things like fuel, water and a holding tank to find space for. Just as an example a Vetus 45l one is 430mm dia and 760mm long. Other manufacturers have different shapes - upright or rectangular, but they are all bulky because of the insulation to make them efficient.
 
mattnj said:
......if there is any good info available on taking a hot water feed off the Thornycroft T90 engine.

Thanks
Click to expand...

As it didn't have a calorifier then the engine take-off and return pipe will either be individually closed off or there will be a rubber hose, starboard side top/front on the engine, connecting the outlet and return points.

I can't remember which was which on my T'Croft 90 (it was 12 years ago!) but the Moody Owners Association will know - if you haven't joined then do so - for the font of all knowledge Moody's
 
Last edited:
Shape may be critical - I had to go with a 22l one (with only a 100l tank) because the 15l model in my preferred range, though big enough in volume, was too long!
 
There is much information about installing calorifiers on my website under 'Engine'.
As a guideline, my Sadler 34 and an Oceanis 36 that we know had 25 litre calorifiers and both, for different reasons, have been reduced to 22 litres. That has always been enough for us although we don't shower aboard, using the stern platform instead. Until I installed a permanent shower there we used to use a litre plastic bottle with perforations in the lid, always enough.
 
My recommendation would be a 20 to 25 litre fed through a thermostatic mixer valve, I have fitted a number of the 25 litre Quick square and 22 l Sigmar Compact, both are very easy to fit and well insulated, the thermostatic mixer valve on the supply will effectively increase the capacity as it takes less of the very hot water from the tank. That setup should prove more than adequate for a cruising yacht provided you don't have people queuing up for the shower.

Edit with more info:
I did a Thornycroft 90 last year, it was fitted with a bowman 180 heat exchanger, from memory I used a seaflow silicone hose that has a 13mm take off stub for the calorifier feed (it replaces the front hose), there is a blanking plug at the rear of the cylinder head, if you remove it you can fit a hose tail for the return.
 
Last edited:
You need less size than you think, because the water in it (assuming a freshwater-cooled engine) will get very hot indeed so you don't need to add much of it to have a bowl of washing-up temperature water.

On the other hand, the warm-up time is also not too much of a problem because the hot water rises to the top and this is where the takeoff pipe is. So you can start extracting hot water almost immediately, even if there's gallons of cold sitting underneath it.

Pete
 
prv said:
You need less size than you think, because the water in it (assuming a freshwater-cooled engine) will get very hot indeed so you don't need to add much of it to have a bowl of washing-up temperature water.

On the other hand, the warm-up time is also not too much of a problem because the hot water rises to the top and this is where the takeoff pipe is. So you can start extracting hot water almost immediately, even if there's gallons of cold sitting underneath it.

Pete
Click to expand...

+1 25l will give you a good 50l when mixed with cold
 
I fitted a 40l Surejust/Surecal on my M376. SWMBO likes to shower/wash hair daily (and if that's what keeps her sailing with me, I'm happy)
Heating up from engine is surprisingly quick - 20 mins gives an amount of good hot water, longer running gets it very hot. Slightly slower to heat by immersion heater but do watch the size of heater element - 750w will be slow, 1.25KW will be quicker but only if you have a decent supply from ashore/generator.
 
wiggy said:
Some great advice above, I would recommend Surejust on the Isle of Wight http://www.surecal.co.uk/Default.32839341, great advice and products.
Click to expand...
++++1 for surecal/surejust. Brilliant product, brilliant service and much cheaper than swindleries.

As a guide, we have a 7 berth boat, but usually sail with 4, with occasional guests. I fitted a surecal 30 litre model, which came with a 1kW immersion and thermostatic control as standard. It heats up after about 30-40 mins of running and stays hot for about 24 hours, (all dependent on use and environment temp). Under normal use we haven't yet run out of hot water, but it's always possible if people aren't careful.

As David says above, the thermostatic control makes a huge difference. After fitting, you need to play about with the settings to get the mix right, but the auto mixing of v hot water with cold before it's delivered makes a huge difference to the longevity of the hot water supply.

The advice was to fit an expansion tank as well. Haven't done this yet, though.
 
When I fitted one in my 36 of asimilar vintage I got the parts for the engine from ASAP, a hose spigot which replaces a blank on the rear of the head and a replacement block to waterpump hose which has a T for a 1/2 inch hose. I fitted calorifier to the bulhead at the aft side of the starboard water tank under the cockpit locker floor with the expansion tank in thr locker itself. I also had to make up a new set of fresh water distribution manifolds under the galley to supply the cold feed and link into the hot tap supply which had been blanked off when the old gas heater had been removed. I think the tank was 25 litres but with the mixing valve set to about 45 degrees we never ran out of hot water.
 
We have a twenty litre Quick fitted. This heats up to engine temp in about 15 minutes. It provides enough for four folks to take showers with a bit left over for the washing up. I wouldn't fit a bigger one even if there was room as the present one makes a good compromise between volume and water usage; if it was any bigger, someone would decide they could have longer showers....
 
KAL said:
++++1 for surecal/surejust. Brilliant product, brilliant service and much cheaper than swindleries. ...
Click to expand...

I am very happy to endorse the Surecal/Surejust comments. Norfolk Marine online had the best prices I could find for the model I chose about a year ago - worth taking a look if going for that make (no connection with Surecal/Norfolk other than as happy customer).
 
You must log in or register to reply here.

Share this page

Top