Building a Donkey Boiler

Thanks Doug, looks like a great setup. I like the concept of an 'Ass Boiler'. Considering my 'Ass' is usually in hot water anyhow.

Do you reckon that is an open system or a pressurised one?

Cheers,

Matt.

Here is a couple of rough ideas to get your brain ticking.
BUT! be sure you have the right relief valve or you could blow it up!
Might be worth talking to a plumber if your not a competent welder as an old hot water service might be a handy tank?

Sorry about the drawings but if I dont do it now IImage Could Not Be Found probably wont get around to it.

Cheers

Thanks Hairy. I had thought about a gas cylinder and you're probably right re the pressure issue. It won't be in use all day, just light a small fire underneath round bath time, then put it out when done.

Cheers,

Matt.

Here are a few things you might want to take into consideration while building it..

One gallon of water could have the same reaction as 1 stick of dynamite.

You are not trying to produce steam, only hot water, but it is quite possibly going to happen anyway.

A given amount of fuel needs a given amount of air to burn—no more and no less. It also needs the right amount of space to burn. Not enough air and you get incomplete combustion. Too much air and you’re heating air.

Bungarra,

Yep, there is some appeal in that type of set up from a safety perspective. If it was to be used just to siphon hot water off, it would probably work well. The difficulty comes (I think) when you try to bring the hot water into the pressurised (cold water) side, say for the shower.

It is only a gravity fed system, but the pressure is significant (as good as or better than most household systems) and, without doing the calculations, the header pipe would need to be very high to overcome the cold water pressure and feed hot water into the system. A non return valve would overcome the cold water back flow, but you would still need significant pressure in the hot water side to overcome the back pressure from the cold. Does that make sense?

He does have an old (electric) hot water heater and (as Hairy suggested) we might be able to use it as a header tank. Just not sure of it's pressure rating, as they are obviously designed (via the thermostat) not to hold boiling water and steam.

Cheers,

Matt.

Darian,

That would be ideal, but unless you are just taking off the hot water to tip into a bath or sink, then I can't see how you mix it with the cold water which is under pressure. In the same way that the system in your house delivers both hot and cold water to the shower (for example) at the same pressure. If you introduce cold and hot water at differing pressures then all that will happen is that the higher pressure cold water will just flow back into the boiler and out the overflow.

I think.

Matt.

Don't forget to fit a magublican or it couls blow up

Don't forget to fit a magublican or it could blow up

Ray,

What's a magublican?

Thanks Phil,

It sounds ideal and I might keep an eye out for one closer to home. Was this one plumbed in to a regular pressure system? I am interested in what sort of pressure you could run through it before overflowing through the shepherds crook.

Cheers,

Matt.

Matt,No it was all gravity, the tank was about 2m. above the hotwater system, Plenty of pressure in the house.We would guite often have the water boiling out the ''crook''. On rainwater, so no pressure tank [use less water] have since put electric heater in, no more lightin the fire. What was really strange , the house also had a solid fuel oven in the kitchen, but that did'nt have a ''wet back'' which meant 2 fires in the winter!! Hope u get it sorted....

Second gravity tank for the cold water fed by a ball cock with the same head as the hot might solve the cold water back pressure problem but it is getting a little complex.

Sounds like a good one Chris, maybe a bit techo for what I am after. Getting hold of kegs can be an issue now as well. So the copper tube actually ran through the hot water in the 10? I guess that is one way to prevent boiling in the pipes.

Matt.

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Thanks Richard.