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Gas califont


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We are looking at installing pressure water and a gas califont. What size califont should we put in? Usage for basic showering and a hot tap at the galley(although i might not connect that). Usually just the 2 of us on board but sometimes guests.

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Best thing we did was goto our showing in our house and turn the shower on.

 

Run it to the temp you like and the lowest pressure/flow rate you'd like and then time how long to fill a 10l bucket. If you have a meat thermometer measure the temp rise and make sure it's within the 25-30deg rise the unit spec's out

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IT, I would disagree slightly here. A good shower with a water saving head should run at around 7-8lpm yet still should give a properly satisfying shower. ( This coming from someone who has removed all restrictions, and put in equal low pressure mixers on our high pressure system ). 2 of the showers in our house run at around 7.5lpm and the unrestricted one runs around 14lpm. All are actually quite satisfying, but I do enjoy the higher flow shower more. Some who use it complain it hurts, and it does cause the water to splash a lot more off your body into your face/eyes.

 

I have never, ever had a shower on a yacht that would flow more than maybe 5lpm - and realistically, how many yachts carry a lot of water for the luxury of a high flow shower? Or do I just shower on yachts with poor showers?

 

I don't believe that a gas califont should not have to deliver the gross volume of the shower at max temp. Our yacht has a Paloma ( sp? ) califont which outputs up to 75 degrees - at about 3lpm. But if we open up the flow restrictor on it we can comfortably get 8lpm at around 40 degrees with a water temp going in of around 16 degrees.. Califonts are more efficient heating a larger volume to a lower temperature than small volumes to high temperatures. Hence the reason that many people install remote controls for their califonts in their homes. 

 

I would think that a califont which could deliver 6lpm at 40 degrees would be quite satisfactory if you do not have a high volume shower ( and pump ) and do not wish to have a luxury shower on your yacht.

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Remember that you may have issues with smaller gas cylinders being able to boil off enough gas to operate a larger califont - our domestic 34LPM rated one will only run for about 5 minutes on a 9KG cylinder before it starts to ice up the cylinder.

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TT, it's been quite a while since I looked at this, you could well be right. My only comment is that there are 2 factors, volume and pressure. The shower needs sufficient water to wet you properly - volume - and sufficient pressure. High pressure with a fine shower head can lead to complaints about pain.

I had some recommendations about this somewhere, I'll see if I can find it...

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Pressure and volume are one part of it. How much water do you guys carry? In our caravan we have a 15l hot water cylinder and by using the wet down, soap up rinse off sequence can get two maybe three satisfactory hot showers by turning off the water flow for the soap up part. However it still uses lots of water and soon fills up the grey water tank. We have 160l of fresh and 130l of grey (and the same black). and we can only just go for a week without having to find a dump station. But will have topped up the fresh water somewhere in that time.

 

Cheers

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We have a resource heavy water system. The shower is darn near a water blaster and it's hot and we love it. But in relation to IT getting 6 weeks, we get 2.
The most common size Caliphont installed on boats is usually 5~6ltr. Ideal for small low pressure water systems. Ours is a big 13ltr unit. The real plus is Dawn can run nearly boiling water into the sink for dishes. 
  You need ruffly a 10'ish l/min pump as minimum. If you don't get enough flow through the Unit, it will shut down. It does not need to be super high pressure. Just 20 to 30PSI is all. The more pressure, the more water you use. We have a 17l/min pump at 35PSI. Way over kill, but lovely shower.
Also, make sure you install 1/2" hose line. I recommend the new Plug and Play stuff. Quick and easy to install and all the fittings have great flow rate. Using plain Hose is a pain because the fittings are so restrictive. Plus the Hot side needs to be able to handle Hot. Most ordinary hose becomes too soft at 60deg.
It is best to have the pump intake as close to the tank as possible, but should that not be possible, go up a size intake line.
Remember that a Caliphont must be vented outside now by law.


 

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Their are now 12V electric water heater available from Australia. A friend has installed one in his Cat and seems happy enough. It means you don't need a fast fitter, just the ability to make amps to run it. A Google search will find it. 

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I have a 240V califont shower in a cowshed. It struggles to give a good hot shower and that thing is 8KW. That thing draws around 34 amps. At 240V. At 12V that would be 680Amps. That is an amazing draw and no alternator I know of would manage that, not even a pair of big mothers. Even if you had a massive battery bank and massive amount of generation, your going to have some serious voltage drop issues with almost any sized cables. 

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Yes it is common to have a " load dump" as an element for Wind generators. But it won't heat the water as such, it just puts some energy into heating the water instead of wasting it heating a Load bank doing nothing.
TT I think he may have been meaning a small 12V cylinder, but it is still a somewhat large power draw to heat water, unless it is just as i have described above.

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Wheels, it still requires the same amount of energy to heat a specific volume of water by a specific amount, and when using a cylinder, you have additional losses as you have storage losses. But yes, its far easier to deliver the energy over a longer time period.

 

I did a rough calculation in my head just now. If your wanting to have 20L of hot water for a shower, - enough for maybe 5 minutes of total shower time once you mix some cooler water with it, you probably need to be heating it by somewhere near 35 degrees above "ambient" water - or around 50 degrees total temp. To heat 20 liters by that much requires around 3Mj of energy - or, a 1Kw element running for around 50 minutes. Thats an 80 odd amp load for around 50 minutes. A challenge for the kind of alternator found on engines smaller than 20 hp, for sure, and unless your alternator is 120a or higher, pretty demanding on the alternator itself. 

 

We have a califont, but we also do have a heat exchanger heated cylinder ( I think its about 10 US gallons - its a yankie yacht ) which can be heated with 240V whilst at dock. Works well, as when we run the engine to freeze the eutectic plates it heats the cylinder to around 60 degrees which gives a good couple of showers or so. The insulation is not so flash, however, so after 12 hours its down to about 35 or 40 degrees.

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