For DIY, and at the risk of sounding like IMM, a heat bank might be more
appropriate than an unvented cylinder if you intend to do it yourself. In
this design, the water within the cylinder is stored unpressurised with
inhibitor, making them inherently safer and not requiring all the safety
features needed by unvented cylinders.
To install is very simple. In fact, they are much simpler than a
conventional gravity cylinder to install. The indirect heating coil is
connected up, just like the conventional gravity cylinder. It requires
pumped flow, not gravity circulation. The cylinder stat is connected up as
before. It needs an electricity supply from the central heating circuit (but
not switched by a programmer). You provide a mains pressure water feed, and
out comes mains pressure water the other end. All the complex feed and
venting arrangements and loft tanks can be removed, making it ideal for
showers in loft conversions, which are impossible to feed using gravity fed
If you convert the hot water to mains pressure, you should do the same for
your cold taps. Otherwise, your mixers (i.e. showers) will be unbalanced and
difficult to control. Also, people might be disturbed if the basin or bath
taps get a trickle from the cold tap and a torrent from the hot tap.
Before you consider this, you must be sure that your mains water supply is
good so that you get good flow and pressure at your kitchen tap.
On Mon, 29 Sep 2003 13:29:17 +0100, "Christian McArdle"
It would still be subject to part L1 requirements, I suspect.
Considering that the water is stored at 75-80 degrees as opposed to
60, for a given amount of insulation the heat loss would be higher as
To email, substitute .nospam with .gl
But then, it stores more heat. The losses due to temperature difference will
be approximately proportional to the temperature rise.
Losses due to the larger cylinder at lower temperature will be approximately
sqrt x in nature assuming a sphere, which is better. However, most cylinders
maintain a constant diameter (450mm) and vary in height. This then puts the
capacity vs loss curve back towards a linear footing.
In all, I suspect a heat bank of similar thermal capacity is probably
fractionally worse than an equivalent cylinder. However, modern insulation
means this is easily good enough.
In any case, I'm sure it would be subject to Part L1. At least, I would hope
HomeOwnersHub.com is a website for homeowners and building and maintenance pros. It is not affiliated with any of the manufacturers or service providers discussed here.
All logos and trade names are the property of their respective owners.