Rival refit q#3: Calorifier - how big?

[alisdair4]

Having now been back to the boat, I have measured where the calorifier is "supposed" to go (under the galley - in what I had thought was a huge waste space). I had thought that I could fit in a 20L, but this is not feasible. I can fit in a 10L one, and saw a reasonably priced one on Ebay. However, is 10L enough for a shower? I know it is sufficient for washing up. Also, how critical is the height of the Caloriifer relative to the top of the engine?

 

[charles_reed]

Calorifier needs to be on a level with the water-pump, at least.

Mine is a 10l calorifier, 20' running gives water warm enough for 2 showers.
The take-off for mine is downstream of the thermostat that opens into the heat-exchanger.

 

[alisdair4]

Calorifier takeoff

Thanks for that, Charles. I think I should be able to get everything below the level of the engine cylinder head. Incidentally do you have a raw-water or fresh cooling system? I have an MD11 which is raw water,and was tempted to try fitting a circulation pump to it to run the calorifier. There are clear instructions on vyv cox's excellent website, so the task doesn't appear as daunting as at first thought.

 

[vyv_cox]

With an electric circulation pump the best location for it seems to be down in the bilge alongside the engine, in the return line from the calorifier to the cool point on the engine. It will then always prime itself.

If the calorifier is higher than the engine it may be something of a challenge to fill it the first time. Mine was like this, meaning that I had to remove a hose at the highest point and back-fill with water, getting the hose back on as quickly as possible. The pump will cope with a small amount of air in the flow of water. Once full there is no problem, air cannot get in unless there is a leak somewhere.

 

[Bosun Higgs]

I can fit in a 10L one, and saw a reasonably priced one on Ebay. However, is 10L enough for a shower?

For you - yes. For SWMBO needing to wash hair - no. For teenage kids - you're joking!

 

[Blueboatman]

10l ? I'd be tempted to boil a kettle and top up with cold water..

Bodgit solution. One of those 20l camping showers laid on deck with the hose fed down into the shower area via a vent or opening port, again topped up from a kettle..

To get more use from the small calorifier might you intend to fit an element and plug in to the leccy?

For what its worth I have 20l from f/w cooled engine and it works an absolute treat, 20 minutes half ahead in the berth and hot, hot hot. I guess you have a direct cooled motor though. "Leccy element might well 'stretch' those showers and prevent domestic disputes..

 

[bendyone]

I have a 22l tank which works well for me. 1.5KW heater takes about 30mins to heat right up.

 

[ff_nick]

Alternatively

20L was just about enough for 2 showers and washing up on our last boat, but we often had problems when guests were onboard. I fitted one of those aerator shower heads (about £20 from ST water), which mixes air with the water, with excellent results. Got a much more powerful, satisfying shower, and the water lasted longer. Consumption went down from about 3.5L/min to 2.5L/min.
I also fitted a single lever mixer (Grone) to encourage people (well me really) to turn the water off while washing (I mean while using the soap, before rinsing), but that cost much more (about £135).

 

[maxi77]

Also make sure you have a mixer valve on the output of the calorifier to moix your hopefully very hot water in the calorifier with cold to both prevent scalding and make your water go further

 

[alisdair4]

Calorifier takeoff -thanks

Thanks to all who have answered the capacity question ( I do take the point about more being better- but 10l is what will fit - and I will fix a mixing valve.

On the issue of calorifier height, having looked at this again today, the top will be level with the cylinder head. The water tank, however, will be considerably lower than the calorifier ( 2.5 feet) as it is in the bilge on the R32. Will this present problems for the water pump, or is this something they are built to handle?

 

[vyv_cox]

On the issue of calorifier height, having looked at this again today, the top will be level with the cylinder head. The water tank, however, will be considerably lower than the calorifier ( 2.5 feet) as it is in the bilge on the R32. Will this present problems for the water pump, or is this something they are built to handle?

No, this is pretty standard. Domestic water pumps are usually positive displacement types so there is no realistic maximum head limit on a boat.

 

[alisdair4]

Circulation pumps

Not to labour the point (well, actually, to labour the point!):

VyV mentioned earlier in this post that the circulation pump should be down in the bilge alongside the engine. With the setup I'm looking at, this means that the hose to the calorifier goes from the starboard side of the engine, down to the bilge and under the floor to the calorifier. Probably 3-4m. Is this within the capability of the circulation pump?

Also, it's not obvious to me where on the MD11c the take-off and return would fit - presumably after the thermostat and before the exhaust elbow? There is only about an inch of rubber hose here, and it all look as if it hasn't been touched since Noah was a boy...!

 

[vyv_cox]

Not essential for it to be in the bilge, just lower than some of the engine's water jacket so that it primes itself.

I don't know your engine well enough to comment. I suspect you have not quite grasped the principle. You don't break into the hose going to the exhaust as this will contain a significant amount of bypass water, which will be tepid at best. You need to take hot water from somewhere on the cylinder head and return it to somewhere cool, low down on the block. This fitting on the Bukh is the drain tap on the original setup, simply replaced by a hose tail.