Gas cylinder boiler.

[Fred123]

I was expecting our old multifuel bolier to give up (heat exchanger split) I decided to knock up a subsitute from a gas cylinder. The results were surprisingly good. Here's a couple of photos below of it. This gas cylinder boiler heats 4 rads (aprox 30,000 BTUs plus stores 180 litres in the the hot water cylider which gives ample hot water in the house. It burns wood or smokless coal. It's mostly made from scrap. Although it draws well, for safety reasons I fitted a glassdoor and shows flame picture.

See comments below for pictures.

 

[stevesteve]

Fred,

That's excelent! How did you set up the water heating part of it? Any pics while building it?

Cheers,
Steve

 

[Fred123]

Sorry about delay in replying,still trying to find construction pics- so for now I can tell you that its two cylinders one 13 kg propane bottle slid inside a 47kg bottle and welded top and bottom. if I don't find the pics I can go into more detail. Thanks fpr your comment!

 

[Pignut]

Brilliant! please go into more detail! that is awsome!

 

[Fred123]

Hi, sorry for delay in getting back to you.
To get started- I ensured safety first and ensured all gas was out of cylinder. Use a suitable appliance to burn off the gas. (If not, make sure its vented off outside.) I then removed the gas valve and filled cylinder completly with water and left for 2 days. After that, I emptied out the water and marked up for cutting. (I used an angle grinder with cutting disc.) I then cut the 12kg propane cylinder just below the dome on both ends. That left me with 300mm x300mm- (That was for the inner part of the heat exchanger.)

I then cut dome off a 47kg cylinder (top part only) and then made another cut 600mm below this. (This was to be the outer part of heat exchanger.)

To seal the heat exchanger, I found some sheet metal (3mm thick) and cut out a circle the outer diameter of the heat exchanger then measured and cut a further circle inside that one,so was left with a washer shape, which I then carefully weld onto the top to seal the exchanger- I did the same again for the bottom (bit tricky!)

Next, I pressure tested the unit by drilling hole at top where flow pipe was to be fitted. Pressurised it with air- in my case it came up at 40psi- well sufficient for the job.
Then drilled again for return pipe at the bottom.

I then cut out a door for the fire box. ( it can vary in size.)Then I cut out ash door. I welded on hinges, as faster,. Used scrap angle iron to construct a fire box door and bought some pyroglass (cost £20 for the piece I ordered) Used firerope to seal it.

Due to the fact couldn't find steel plate to weld to the top for a flat top - was in hurry to get on with it, welded back dome minus carring handle. Fitted 5'' flue. After installing, carried out a smoke test. ITS VERY IMPORTANT as CO poisoning is more comman than you might think. This boiler is for open vented systems only and must not be used on sealed systems.

Hope this explaination doesn't seem to arrogant as I haven' t
been too detailed. Any questions- please ask.

 

[Fred123]

Forgot to say thanks for your comment!

Fred

 

[demographic]

So is it an open vented system or is there a chance you could take the street out if it gets too hot?

 

[Fred123]

As I stated earlier, it's open vented and it often gets too hot as is common with solid fuel boilers. As for taking the streetout - it's a domestic boiler not a weapon of destruction!!

 

[demographic]

As I stated earlier, it's open vented and it often gets too hot as is common with solid fuel boilers. As for taking the streetout - it's a domestic boiler not a weapon of destruction!!

Sorry I missed the bit where you mentioned it being open vented (my fault for not reading it properly, sorry) but as I used to radiographically inspect the welds on pressurised steam boilers I was just making sure.
If it had been a pressurised boiler its worth pointing out just how dangerous they can be and they really can make an awfull lot of damage if they fail.

Carry on, err as you were