DIY Hot Water Heater <> Exchanger. Please comment!!

[moseriw]

Order it abroad:

https://www.svb24.com/en/quick-warm-...boiler-b3.html

(not really cheap)

[RaymondR]

I have a HWS on my boat with a calorifier from the engine and also have a camping gas heater tied into the system so I don't have to run the engine to have a hot shower. Unfortunately the gas system wastes about 6 litres of water whilst heating up so I tend be reluctant to use it and am thinking of having the gas heater heat the water in the hot water tank using a circulating pump. This will probably switch the system from being water wasteful to gas wasteful.

When I built the panel mounting frame for my solar farm I provided space to allow the use of different sized panels in the future and am thinking of trying out running copper pipe painted black in there and a circulating pump with an intermittent timer to implement solar hot water.

[Mike Crothers]

Be careful you don't poison yourself with leakage of the high pressure antifreeze into the low pressure water system if you plan on using the hot water for drinking or cooking.



Also make sure the copper tubing is compatible with the antifreeze and engine metals. I don't believe engine cooling bundles are plain copper.


Good luck and be careful. I talk to a couple using a simple camping propane fired on demand heater and love it and very cheap, at least from US Home Depot.

[Ric Sheridan]

If you are an American living in Brazil you can bring in one 40ft container every two years tax free. If you brought in boat parts you could make a killing on the Black Market. Plus if you shop around you can find Paloma type water heaters for cheaper than $1000. I did for my mother in-law. Funny thing is by the way is that the majority of Brazilians don't have hot water. They use the little shower heads that heat up the water electrically (which is a shocking experience if not done right). You might just want to use one of those considering the price and your battery situation.
Also I might add that I heard from more than one friend that if your boat is under foreign registery that you can moor at almost any harbor or yacht club for free. IDK it was I heard.
Just my 2cents worth.

[Shaneesprit]

Originally Posted by moseriw

Order it abroad:

https://www.svb24.com/en/quick-warm-...boiler-b3.html

(not really cheap)

Would be great if that ran on diesel or gas (not petrol)
Would probably have to be diesel as the exhaust flue on gas is too large.

Not sure what AC power the OP has available, but he was looking to use engine heat.

He would probably have to get someone in the EU or USA to buy it and post it to him?

Last time I had something sent to me in South America it was delivered about 3 months later when I was back in the UK.

[goboatingnow]

You can use a conventional small domestic hot water tank fitted with an indirect coil , ie the hot coolant runs through the coil, a pressure relief Valve is useful , you don’t need an expansion tank nor do you need any form of check valve on the cold water supply , as this is behind the water pressure pump. , I had exactly this system in my previous boat. Don’t not worry about the coolant run m if within 1metre of the engine , position the hot tank near the engine as possible.

A thermostatic mixer on the hot water output is a nice to have , I never had one for years.

And yes plain copper is fine for engine cooling , don’t overthink this.

I’m sure in Brazil , there are local copper tank manufacturers , they can do a custom size easily.