Anyone have any views on Hydraflo unvented cylinders?
http://www.chaffoteaux.co.uk/pdf/hydraflo_um.pdf
http://www.chaffoteaux.co.uk/hydraflo_indirect01.htm

I'm thinking of having an one put in. My existing airing cupboard is
not very big and it can't really be enlarged without obstructing a
doorway into a bedroom. Hydraflo have the smallest diameter of any
unvented cylinder on the market (505mm) which would just about fit
with room for the pipework.

Strangely I can't find any thread in which they have ever been
discussed on the Google archive. My main concern is that they only
have a five-year guarantee, whereas Megaflo for example have 25 years.

If they're really rubbish my only option would be to get a Megaflo but
put it in the loft, which would mean some joist strengthening I would
think.

If they're really rubbish my only option would be to get a Megaflo but
put it in the loft, which would mean some joist strengthening I would
think.

What size are the joists?

If I was fitting it myself (as I was), I would definitely be looking for a
loft installation. Even relatively shallow joists will be strong where they
cross a load bearing wall. I just put mine near such a crossing and laid a
thick layer of ply to spread the weight a little. However, there are some
strange loft ceiling designs out there that would indeed be completely
unsuitable.

You may find that your loft already has a cold water tank that you could
remove. The new cylinder would weigh less than a 50 gallon cold tank and
could be a straight swap, as you won't need the tank afterwards.

If you are doing the work yourself, I would strongly recommend that you
consider a plate exchanger heatbank instead of an unvented cylinder. These
are much easier to install, don't require pressure relief and overflow
pipework and don't require ongoing safety inspections as there isn't a huge
unvented pressurised vessel in the design.

Christian.