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Marine Hot Water Cylinder Recommendations


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This sounds like a hydronic heating system (that sends hot water around the boat in small pipes) rather than an airtropic (forced heating) system which blows hot air around the boat in big tubes. Both use diesel heater at the beginning but hydronic (water) much more efficient at transferring heat long distances without big losses. Airtropic become useless on say mono over 45ft or most cats (might be why BK has it)?

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I got Marine Electrics to do the install

 

The hot water is Water Heater. Sigmar. 40L 1200W 220V. Quick and its under the after berth, which is right next to the engine...the diesel heater is in the engine bay.

Its a Eberspacher, D5WSC Marine Kit, 5.0kw, 801 Controller, 12v

 

BK will need to explain the heating has he has piped his, I havent bothered as yet as Im generous enough to let my kids play winter sport, so no winter cruising

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We have an Eberspacher hydronic, which heats a glycol/water mix (just like antifreeze in your car, but a bit thicker, maybe 50/50 mix?)

This gets pumped around the boat, we have it going thru the hot water cylinder, and thru 3 heaters. 1 in each cabin, and a double size in the saloon.

The heaters just run a little fan like a PC fan.

If you get organised you can even bend up some stainless tube into a towel rail, and have a heated towel rail.

The heaters look like this

Image result for eberspacher hydronic heater matrix

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The thing is super reliable, uses almost no diesel, the fuel line looks like the inside of a ball point pen, about 2mm diameter.

It heats the water cylinder in about 10 minutes, and can heat the whole boat in winter in about the same.

Wouldn't build a boat without it. 

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Ok, thanks for the info. I'm now thinking my system might look like:

  • Mount a 40L hot water cylinder behind my port engine. It will be below the radiator cap on the heat exchanger, so bleeding should be OK. I guess bigger would be better but I've just removed a 120kg generator from this space and don't want to put weight that far back in the hulls. 
  • I'll order a Cylinder with twin coils to future proof myself. One for engine now, one for a future diesel Hydronic Heater.
  • Leave space for a Hydronic heater for possible future expansion if we want heating to extend winter cruising or if we liveaboard in future.

Seem reasonable? 

 

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51 minutes ago, Island Time said:

The flue install can be an issue though.

 

 The flu is my issue. The Califont is on the back of this wall where the blue box is, with no wall above, or anywhere to  run a flue. We don't really have any other good locations. 

I have just found photos from the lunching in 2007 showing the same califont in the same location, so maybe I do check the applicable regs from then and argue it is still legal.

image.thumb.png.0b68bd5929610c509bb719ec6b777235.png

Lady Nada Original  ph  47.jpg

Lady Nada Original  ph  48.jpg

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Does anybody have a copy of the 2003-2010 Gas Regulations?

Actually it might be the NZS 5428:2006 LPG installations for non-propulsive purposes in caravans and boats that my 2007 boat needs to comply with.

 

 

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2 hours ago, ex Elly said:

You can also set up a diesel heater like a califont, so you get near-instant hot water, and no need for hot water cylinder.

 

Eberspacher do one of those, called a Hydroplate. 5ltrs tank, but as ex E said,  continuous flow. 

But then heating with engine would be a problem, so maybe no good for you. We're putting one in our 4WD campervan build.

image.jpeg.86182a9d088f062824452d0b9218db69.jpeg

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Hey Adrian

Scott has the piped hydronic system on Muskoka. Once you are let loose, happy to show you his set up. We will be in Whangarei Oct&Nov at least as Ellen has got a short-term job there for a couple of months.

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4 hours ago, Adrianp said:

 

 The flu is my issue. The Califont is on the back of this wall where the blue box is, with no wall above, or anywhere to  run a flue. We don't really have any other good locations. 

 

 

do you have any space on your cockpit bulkhead to tuck it in a corner and run a flue thru the cabin top, such as the corner behind the owl in this photo

image.png.1d0172bd860fc46f2b946f29f3902b57.png

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On 24/09/2021 at 5:20 PM, marinheiro said:

do you have any space on your cockpit bulkhead to tuck it in a corner and run a flue thru the cabin top, such as the corner behind the owl in this photo

image.png.1d0172bd860fc46f2b946f29f3902b57.png

Unfortunately not as our walkways to the hulls are right at the bulkhead and the califont would be right in the way. Please excuse the mess in the photo!

I could actually put it outside on the back of the bulkhead but that feels like a great way to take a zero maintenance item and turn it into at rusty maintenance nightmare!

PANO_20200805_200834.jpg

DSC_0930.JPG

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5 minutes ago, Adrianp said:

Unfortunately not as our walkways to the hulls are right at the bulkhead and the califont would be right in the way. Please excuse the mess in the photo!

I could actually put it outside on the back of the bulkhead but that feels like a great way to take a zero maintenance item and turn it into at rusty maintenance nightmare!

PANO_20200805_200834.jpg

DSC_0930.JPG

you could mount one of these in that exterior corner, just need a flu thru the hard top

https://challengeyachts.com/challenger-6l-lpg-water-heater-stainless-steel.html

I had a califont set up on the outside cockpit bulkhead on a previous boat (a launch) and once I replaced the painted steel enclosure with one in SS no further corrosion issues

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Anyone thinking about cutting corners on a gas install should read this. Anyone else who ever uses propane on a boat should read it too:

http://www.boatmoves.com/LT_Story.htm

Lord_TrenchardL.jpg

 

and watch this:

 

They used a tiny amount of gas for that explosion from a little camping cylinder from a portable stove. It could have been much worse!

NZ regs and awareness of propane risks are really lax compared to the UK. I've seen some really terrifying stuff here like gas bottles in the bilge!

Gas bottles and things like califonts must always be in a place where the gas will drain overboard if it leaks. Any gas appliance like a cooker mounted insode the boat must have a flame failsafe and a gas alarm at the lowest point below it. The trouble is those califonts go very rusty if you put them outside so you can't win. They really have absolutely no place on a boat one little fault and you're dead.

Having an install which pre-dates the safety regulations doesn't make it safe. I hate bureaucracy but this is one case where the rules are sensible and do save lives.

Diesel hydronic heaters together with a hot water tank are a good option but be warned they can be noisy, the installation can be a lot of work and they tend to be too powerful just for hot water - they cycle on and off unless there is plenty of load on them (just a hot water tank with a coil wont work, you need a few heaters too otherwise the circulating water will overheat and turn the heater off without dissipating much heat into the hot water cylinder. I guess you could circulate the shower water directly through the diesel heater and back into the cylinder instead of using the heating coil, that might work.

Diesel air heaters tend to create a problem with ducting the hot air through watertight bulkheads and across the bridge deck. On a cat you need the hot air ducted to the bottom of the hulls in every compartment so hydronic heating is usually best but hydronic heating can be heavy for a cat.

We have agonised over similar problems, at the end of the day the best solution will depend on the layout of your boat. Electric water heating can be an easy option if you carry a genset, have shore power or have more solar power than you need.

You can also look at an old fashioned diesel stove with a chimney, or even a woodburner and use a "wetback" coil of pipe inside the heater to heat water. Depends on whether you enjoy tinkering with the fire and have plenty of time to wait for it to get hot! Works if you have the heater on all the time anyway, not very useful if you want hot water in summer.

 

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Regarding explosions due to califonts: apparently only 2 boats in Australia and none in NZ. 

If you isolate the califont when not in use, shouldn't be a problem.

 

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5 hours ago, ex Elly said:

Regarding explosions due to califonts: apparently only 2 boats in Australia and none in NZ. 

If you isolate the califont when not in use, shouldn't be a problem.

 

Got a source for that??

Most marine califont units have flame sensors and oxygen depletion sensors. I would not have one without. Any boat with gas should have a gas detector.

Anyone with a gas bottle in the bilge is an idiot.

Usually you will smell a gas leak. I've had a couple in Island Time - in the "approved" copper tubing - it corrodes, and does not like movement. In both cases I could smell it, and shut off the supply. Pressure tested with air, soapy water etc, located and repaired the issue (not in NZ, SE Asia, no regs!) Actually petrol is more dangerous, as it's harder to smell, and many carry that for the dinghy engine. Keep it in a proper vented locker! 

A while ago I had a gas heater (at home, not the boat) failure, and replaced it with a heat pump. I crimped and soldered the end  of the copper gas supply line. Then got a registered gas fitter to have a look and sign it off. He looked at the crimp, pressure tested, and then signed it off no issue. Repairs are not hard, just be sensible! Gas is not rocket science.

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21 hours ago, syohana said:

I've seen some really terrifying stuff here like gas bottles in the bilge!

Yep, my friend just bought a boat where the gas bottle just lies in the bilge under the gas oven!

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