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Very small simple hot water system off back boiler?

Posted: Sun Nov 16, 2014 7:54 pm
by peat
I live off grid with a pretty basic set up. No running water, but rainwater collection. I am just finishing building a fancy bender living room/ kitchen space that is about 15'x15'. I've just bought a beautiful used Jotul 507, which I didn't realise until I went to collect it, has a backboiler. (It was still plumbed in when I arrived to pick it up, which was interesting as the owner had no idea where any of the stop cocks were...)

Now, I hadn't been looking for a stove with a back boiler, but now that I've got one, i'm wondering if it would be feasible to set up a small hot water system around it. Currently all my hot water comes from a kettle on the fire, but after a few years without hot running water, it seems appealing. However I am a seasonal forestry worker, and so will likely move on to another woodland sometime in the next few years, so I don't want to create anything that is too complex, expensive or bulky for when it comes to tatting down. What would be the simplest possible system for running off the backboiler? I'd only want a shower and a tap (mixer I suppose to avoid getting scalded. I imagine the there must be a fair few people on barges with a back boiler system, where space is a premium. Any thoughts?

Re: Very small simple hot water system off back boiler?

Posted: Mon Nov 17, 2014 2:04 pm
by doofaloofa
I'm not a plumber but here is the basic idea

Boiler takes water to an imersition tank where it indirectly heats the contents of the tank

The boiler is fed from a small tank

You need an expansion pipe on the flow pipe from the boiler. This may vent boiling water so watch where it points

A radiator is used as an emergency heat sink

The imersion tanks needs a supply and a tap to accesss the hot water

A drain cock on the lowest part of both systems will aid in emptying

The botom of the imersion tank should be 4" above the top of the boiler

Full imersion tank V heavy

Re: Very small simple hot water system off back boiler?

Posted: Mon Nov 17, 2014 2:33 pm
by ojay54
I had a narrowboat with a Morso dove running a backboiler connected to a rad about 20' down the boat.As it was a thermosyphoning system it was pretty important to get the correct angle on the top pipe to the top of the stove and to have the header tank in the right place,and it has to be 28 ml.copper pipe.On the face of it,to develop this system as a shower would seem difficult,but I'm sure as with all these things some anorak will have found an ingenious way round the problem.
Personally I would look to simplify the whole job by utilizing the heat from the chimney i.e. have a simple system involving copper pipe wound like a snake around the flue this would save all the problems of angles/insulating the hot pipe etc,and be easily taken apart and reconstructed.Best Wishes.