Hot Water

oakleyb

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I want some hot water on board, i'm looking at either calorifier or gas water heater. The problem with calorifier is i have raw water cooled engine - i've been told this arrangement will not heat water, but i could use shore power or generator to heat. Not sure on the gas option
 

VicS

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It may depend on the engine but calorifiers can be fitted to directly cooled engines.

They run cooler than fresh water cooled engines so you will not get the water as hot.

I have gas water heater... its called a kettle!
 

RobBrown

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There are previous threads on this as it comes up pretty often. It is perfectly possible to get decent amounts of hot water from a Raw Water cooled engine, just not as hot as from indirect. Main advantage of that means dont have addl expense/complication with a thermostatic mixer valve. How do I know? Cos I've had a calorifier connected to my raw water cooled Bukh for the last five years. Main suggestion with a raw water cooled system is have a decent circulating pump. I've got a Johnson included with a take off kit supplied by Bukh.

Snap
 
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planteater

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The idea of pumping hot seawater anywhere other than back into the sea sounds like a recipe for flooding to me. That is pretty corrosive stuff. If outboards require different treatment in salt and fresh water then I'm sure the same would apply to calorifiers.

I am tempted to get one of those catering sized vacuum flasks with a hand pump built into the lid that you see in hotels and meeting venues. No good for a shower but you could get half a days worth of hot drinks out of it.
 

salinia

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Our hot water is supplied via Origo via kettle via 3litre pump pot, not very grand but suffices our needs.
5373041641_be155db374_z.jpg
 

PetiteFleur

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I want some hot water on board, i'm looking at either calorifier or gas water heater. The problem with calorifier is i have raw water cooled engine - i've been told this arrangement will not heat water, but i could use shore power or generator to heat. Not sure on the gas option

I don't think gas water heaters are approved for boats - contact SOCAL for more information, they are the experts on anything gas. http://www.socal.co.uk/Marine/9
 

vyv_cox

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I want some hot water on board, i'm looking at either calorifier or gas water heater. The problem with calorifier is i have raw water cooled engine - i've been told this arrangement will not heat water, but i could use shore power or generator to heat. Not sure on the gas option

There is a page on the subject on my website. On some engines, Bukh in particular, it is extremely easy to set up as the blank plugs are already in place. I believe that raw water cooled Yanmars have connections that can be used. Someone more knowledgeable about Volvos may be able to advise. On some older engines forumites have drilled and tapped connections where none existed.

However, it is unlikely to work on smaller single cylinder engines bcause insufficient heat is generated by the engine, which will run cool and suffer accordingly.

The hot water obtained from a raw water engine is slightly cooler than that from a fresh water one but you will be hard pressed to tell the difference. Water from the calorifier with my Bukh engine was too hot to put your hands in after about 15 minutes of motoring.

The mistake that many make is to divert the flow between engine and exhaust manifold through the calorifier. This will not work because a large proportion of the raw water bypasses the engine and the overall temperature is low.

The idea of pumping hot seawater anywhere other than back into the sea sounds like a recipe for flooding to me. That is pretty corrosive stuff.
Hot water pumps through the heating coil in the calorifier and back to the engine. It's very similar to a car heater or the same arrangement with a fresh water cooled engine. No reason why flooding should result any more than it does in these others. There are thousands of boats that have this system. Sadler used it on all the boats they built with pressurised hot water.
 

rob2

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I've never quite understood the ban on gas water heaters without an external flue. Yes there is an asphyxiation risk but it doesn't seem any greater than using the oven for an extended period. The only circumstance I can envisage that would be definitely dangerous would be to rig the heater as a cabin heater!

IIRC indirect cooling thermostats are around 80 degree setting, whilst direct cooling is around 70 deg to minimise the corrosive effects of hot saltwater. The indirect temperature regime promotes a more efficient running temperature for the engine. Either is likely to be hot enough for general washing.

Rob.
 

vyv_cox

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I've never quite understood the ban on gas water heaters without an external flue. Yes there is an asphyxiation risk but it doesn't seem any greater than using the oven for an extended period. The only circumstance I can envisage that would be definitely dangerous would be to rig the heater as a cabin heater!

I agree. It seems no more dangerous than boiling a kettle. I had one on my GK29, it worked well and was rarely on for as long as a minute as the water tank was pretty small. After I sold the boat the new owner needed an insurance survey, during which he was advised that the heater was incredibly dangerous and would need to be removed immediately. Seemed like a knee-jerk reaction to me but there was no way around it.
 

AntarcticPilot

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There is a page on the subject on my website. On some engines, Bukh in particular, it is extremely easy to set up as the blank plugs are already in place. I believe that raw water cooled Yanmars have connections that can be used. Someone more knowledgeable about Volvos may be able to advise. On some older engines forumites have drilled and tapped connections where none existed.

I have raw water cooling on a Volvo Penta 2003, and have a calorifier that was fitted to my Moody 31 from new. It provides water that is amply hot enough for washing. The take off is from the pipe between the thermostat housing and the exhaust elbow; the original solid copper pipe has been replace by two elbows, from which the pipes go to the calorifier.

The only snag is that the calorifier is a type meant for vertical installation, and it has been installed on its side - this is on my list of things to sort out, if space permits, as it means that it is incredibly difficult to bleed air from the system.
 

dje67

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On my previous boat, I fitted a 10l Surecal calorifier with a 1kW heater. The engine was an MD11c, raw-water cooled. I never bothered plumbing the calorifier to the engine as it didn't seem particularly simple to do so on this particular engine. I had a marina berth with shorepower. Most of my sailing was day-sailing and the small tank was fine for taking some hotwater for hand-washing and dish-washing. It would stay warm overnight, so worked for the odd overnight at anchor. Most marinas had shore-power, so getting the tank re-charged was never much of a problem.
 

rudolph_hart

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I want some hot water on board, i'm looking at either calorifier or gas water heater. The problem with calorifier is i have raw water cooled engine - i've been told this arrangement will not heat water, but i could use shore power or generator to heat. Not sure on the gas option

I have a Truma gas + immersion water boiler, which was fitted as original kit by the builder (Dehler). I'm pretty sure they're used in caravans & motorhomes as well (i.e. there is no special 'marine version')

It's fitted right aft in the cockpit locker, and has a 'balance flue' through the cockpit side (behind the helm) with a removable cover. Heats 14 litres water for cockpit or toilet shower in about 10-15 mins.

It has its own separate gas valve shut off & control/thermostat (similar Eberspacher) in the toilet compartment, and a separate switch for 'immersion', which we only use on shore power.

Simple to use and still reliable after 16 years :)
 
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snowleopard

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All raw-water cooled engines have two streams of water. One goes through the block to cool the engine and one bypasses the block to provide cooling to the exhaust while the thermostat is shut. The flows separate after the pump and merge somewhere between the exit from the block and the exhaust injection point.

If you take the feed to the calorifier off after the point where the two streams merge the result will be no more than tepid. To get hot water you need to tap into the flow from the block before the streams merge. In Yanmars that is tricky as they merge right at the thermostat housing. You can get round that by making a bypass hose. If anyone wants to do it I can email a diagram.
 
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