Domestic Hot Water Cylinder as boiler/HLT

[spook100]

Hi
I was wondering whether a domestic combination hot water cylinder would work as a boiler/HLT? They are generally made of copper, they're already insulated and ready for an immersion heater and outlet pipe. All that would need to be done is to cut an opening between the hot water tank at the bottom and the cold water tank at the top; the cold water tank would act as a good reservoir in the event of a boilover. I would think one would be able to pick one up on ebay at a reasonable price. Any thoughts?

[Kev888]

Hi,

I've seen some posts on this before, where people had used the normal indirect (no reservoir) cylinder and turned it upside down with the bottom cut off - the immersion heater and outlet that were previously in the top were then at the bottom.

I'm wondering about something similar for a HLT. My reservations for the boiler are that the wort will attack it faster than water, and they're quite thin things and not especially robust particularly if you remove the top - think they're only guaranteed for a short while even with water (I looked at the stainless pressurised cylinders on fleabay, but not seen any going cheap - even used ones are still costly compared to big stock pots and so on). Used copper cylinders are quite plentiful on ebay and so do seem very good value compared to stainless for big metal tanks though - very tempting - just not sure if stainless would be better value over time.

Cheers
Kev

[spook100]

I take your point about the wort corroding the copper but the length of exposure is a lot less (a few hours at a time) than it would be to the water when used for domestic heating (24-7-365). I would think it would hold up.

[grmills]

I used one as a boiler for about ten years, never any problems with corrosion.

[Kev888]

I used one as a boiler for about ten years, never any problems with corrosion.

Sounds good - I guess some breweries use copper a lot too, so it can't be eaten away all that quickly.

I think on reflection the main thing that put me off about hot water cylinders previously is their physical weakness if cut open, compared to the massive weight of their contents; the modern ones in particular seem very thin. But i guess with care they would be okay, and maybe leaving part of the shoulder/rim on and/or some sort of external support would completely get over that if it were a problem anyway.

Cheers
kev

[Kev888]

This has spurred me on to have a go at using one for a HLT (my current burco is great, but a bit small). Anyway, I just won a used 117l copper cylinder on ebay, complete with the moderrn sprayed-on insulation, for less than the cost of a blue plastic bin Seem to be quite a few of them up for sale actually, but most are local pickup only so I guess its down to luck if no-one else in your area is bidding seriously for one at the time.

Its just a standard cylinder, nothing as posh as the one pictured in the OP, but it looks fairly clean inside. I was going to invert it, but the element in the top is only a bit off vertical so would stick out of the water during smaller batches (especially once just the sparge water is left in there). So i'll probably save on making a cradle for it and use it the way up intended, by adding a horizontal immersion at the bottom instead. Soldering a flange in wouldn't be easy because of the insulation, but I'm hoping a screw-fit flange would be strong enough to pull the wall flat around it. Found this but I'm not sure if its the right thing mechanical flange

Not going to leap into it though - i started bidding lowish amounts on the assumption that 'at some point' I'd get one with no competition, wasn't expecting it to happen so soon!

Cheers,
kev

[spook100]

Kev

I used a mechanical flange when building my existing boiler. My boiler is made from a stainless steel milk urn with quite a thick wall and I wasn't able to pull the wall flat with the flange. I have a 2 1/4 inch immersion heater so bought a 64mmx5mm o-ring (http://www.bearingstation.co.uk/product ... tNo=OR64X5) for £2.34 including postage. It did the job perfectly.

How about some pics of your boiler project?

Bruce

[Kev888]

Hi Bruce,

thanks for that - could be useful. Think i may have a go without extra washers first, as the copper walls are softer than stainless and seem quite thin too, but if it doesn't work then your o-ring idea could be ace.

My weekends are a bit full for a few weeks so there probably won't be instant action, but i'll definately take some pics as I go and post them (if its not a complete shambles anyway )

Cheers
kev

[Kev888]

How about some pics of your boiler project?

I started a thread on the conversion with pics here - though its got a long way to go at the mo.

Cheers
Kev