On Tue, 8 Jan 2008 01:36:00 -0800 (PST) someone who may be
wrote this:-

However, there is also an ensuite in the
attic that is supplied by an Ariston Classico unvented electric
immersion heater (model STD 125). The tank has 2 immersion heaters,
one at the bottom and one at the top and according to the manual, the
bottom one is for night time and the top one for a day time top up. I
understand this is typically for use with Economy 7 tariff. Each
immersion heater is wired to a separate mains switch.

That is the case. The bottom one would come on automatically at
off-peak periods to warm the whole cylinder. The (expensive) top one
would be switched on as necessary to top up the cylinder
temperature.

The previous owner told us that in order to get hot water we should
turn on both immersion heaters for a few hours.

The top one should be adequate to heat enough water for a shower and
general washing. If it isn't then perhaps you spend too long in the
shower and are using as much water as a bath would:-)

Is it advisable to put a timer switch that will
turn on both heaters for a couple of hours each morning? Or separate
timer switches for the two heaters?

Personally, as a first stage, I would put a timer on the top
immersion heater. Models are available which replace an existing
switch. I would ignore the bottom heater. This can be set depending
on usage, for example on all day or on twice a day as appropriate.

After that I would consider the options. Why does the en-suite have
a separate storage system as opposed to being connected to the main
storage? Unless there are long pipe runs due to a badly designed
room layout few houses are big enough to warrant more than one
source of hot water.

Depending on the answer to this there would be many options for a
more permanent solution, depending on inclination and circumstances.

One idea that might fit some situations is to fit a retrofit heater
battery in place of the lower immersion heater. This could take hot
water from the boiler or a solar panel. Such heaters are not ideal
due to their low surface area, but they avoid the disruption of a
new cylinder.

Any advice on a simple setup would be much appreciated. btw, we're
not on economy 7.

Then heating up the whole cylinder with the bottom immersion heater
will be expensive. I would avoid using it.




--
David Hansen, Edinburgh
I will *always* explain revoked encryption keys, unless RIP prevents me
http://www.opsi.gov.uk/acts/acts2000/00023--e.htm#54