Hot Water Cylinder HLT - pics

[Kev888]

Well, following this thread I won a hot water cylinder on ebay, which I'm going to convert to a HLT. This is a going to be a photo record of progress.

This is the tank with the top cut off and after removing a couple of inches of the foam lagging:

I reckon the 117l cylinder will have at least 90l left after removing the top, even without a syphon effect outlet.

The metal is very thin - you can easily flex the rim with one finger and I'm sure it would be very easy to dent. If this were a boiler, being upended and cleaned out regularly and so on, I'd definately want to re-inforce the rim somehow, but as a HLT (which I'll probably leave more or less alone aside from filling and emptying) it may be okay as is - not decided yet.

I had originally intended to use the cylinder upside down and cut the bottom off instead, to make use of the existing immersion setup. However, the immersion was locked solid and seemed to have suffered some sort of burn out. More importantly though it was almost vertical - smaller batches and the latter part of sparges would leave it sticking out of the water as this photo shows:

So I'm now going to use it the right way up and put an immersion in horizontally, towards the bottom somewhere.

This is the inside, with the coil which i'll remove next:

I'm thinking of using the upper coil hole to poke a temperature sensor in. I may use the lower one as the drain or sight tube connection, but its a little high. There's also the original connection for the cold water feed lower down.

There's a bit of green and some scale but its not too bad at all. The metal is quite smooth inside so hopefully will clean up fairly well. I'll probably use a scratch-free kitchen scrubber, and possibly some cleaning fluid if I can find anything reasonably powerful yet also okay for copper.

Thats all for now

Cheers
Kev

[Kev888]

Cut out the coil this evening; its beginning to take shape. I also fitted a mechanical flange for the immersion heater:


And here's the flange outside and in. I tried to make the hole with a holesaw but the metal was too thin - bent under the pressure and the centre drill wandered. A q-max cutter would have been better but I don't have one, so I drilled a circle of smaller holes and filed the resulting hole round (happily the metal was so thin that this was actually quite easy). Lets just say there'll be no problem flattening the cylinder tight to the flange.

EDIT: I'm not sure in retrospect if the flats on the internal part should go vertically or horizontally; the tank is flexible enough that, rather than fitting to the curve (as I have it), it may be meant to flatten the curve against the outer part and washer - but in any case, it seemed to work this way for me.

Its beginning to look quite potential now - and is cleaner than the pics make it seem. I was probably lucky with my ebay bidding but I've still seen quite a few go for less than 50 notes before I won mine - it seems great that you can get a non-ferrous lagged tank this size for so little, especially if like me you're a little dubious about heating in plastic. That said, I suspect something catastrophic happened to the original immersion heater which couldn't be removed - looks like it had boiled dry - so I may have been much less impressed if I'd been buying it to use in the normal way.

Cheers
kev

[haz66]

Nice conversion there Kev,looking really good

[floydmeddler]

Very nice! The green meanie breathes...

[Kev888]

Nice conversion there Kev,looking really good

Cheers mate. Its a long way from your superb setup of course, but I'm quite pleased with things so far - just hope it continues that way!

Kev

[Kev888]

Very nice! The green meanie breathes...

Haha! yes it is a tad vivid. If it goes well I may think about enclosing or wrapping it in some way, but its probably premature for aesthetic tinkering as yet.

Cheers
Kev

[WishboneBrewery]

So that is how big the heat exchange coils are in a tank!
Looks an Interesting project.

[befuggled]

A beautiful creation Kev! - I was always too worried about the thickness of the copper, but you seem to have got that sorted
Nice pictures, keep up the good work!
I have just found out that Armaflex insulation does not come cheap....

[leedsbrew]

Cracking that mate.

[Kev888]

Thanks for all the encouragement, chaps. I'll keep posting pics as I go

Cheers,
kev

[leedsbrew]

Cracking that mate.

[Kev888]

it looks like the fibre washer needs to go on the inside otherwise there is a leak path behind the flange and up through the threads, or you can turn the whole arrangement round 180 deg so the flange and fibre washer are on the outside (but I presume the immersion will be pointing in the wrong direction then.)

Thanks for taking the trouble to look at it that closely, much appreciated!

Its a bit deceptive though, and I had to think twice about it as well: The outside part of the flange is sealed by the washer to the outside of the cylinder, and then the immersion will be sealed to the other end of the outside part of the flange with its washer. The inner part of the flange is just to physically hold the outer snug against the cylinder wall really, it doesn't matter that water will get in the threads as they're still inside the sealed volume.

Not perhaps ideal for cleaning, but the only alternative I had was to use the immersion heater directly with a backnut, and that would also seal at the outside (as immersion heaters are designed to do). One of the downsides of the cylinder being pre-lagged I guess, you can't solder a normal (and considerably cheaper!) flange on without burning the insulation.

Thanks again though - any help in avoiding even possible cock-ups is worth its weight in gold!

Cheers,
kev

[grmills]

You don't need to get too uptight about cleaning, it's a boiler and everything within gets boiled and killed off. (You should have seen the state of my old one after a few years...)

[Naich]

Shame you couldn't use it as a boiler - it already had a heavy duty IC built in

[Kev888]

Shame you couldn't use it as a boiler - it already had a heavy duty IC built in

Yes, its almost a shame to remove it and I may well have tried it if I were making a boiler, but I've already got a second hand stainless tank that I'm going to use for that. I've not thrown the coil away, though

Its interesting actually, that this sort of monster coil (in something like 1" diameter pipe), is considered the optimum for exchanging heat in central heating systems, whilst we tend to go the opposite way and use considerably longer narrower tubes for our ICs. I guess central heating systems need to avoid restriction in the flow rate or something like that, and being re-circulated there's no concern about the amount of water passing through.

Cheers
kev