"Jeff" wrote in message
...
I have spent the best part of today trawling throught the archives and am
more confused than ever :-(

(I feel as though i know IMM personally)

That is nice.

the situation will be 4 bed semi with
bath/shower room and ensuite shower
room + ground floor granny bedroom
and ensuite bathroom

2 adults, 2 teenagers + 1 OAP

OAP bathes once a week
other occupants shower daily with very
occasional bath

we are used to a triton 9.5 kw shower
and pretty poor bath filling due to
the cold water tank emptying if using
hot and cold together (conventional
antique system)

the archetect specced an unvented
cylinder but the plumber says the cold
water main is not up to the job (15mm lead)

I have concerns about fitting 2 electric
showers (2x40amp out of 100 don't
leave alot) I had a bad experience with a
combi 20 years ago, forever to fill a bath,
but am looking at the Bosch Worcester 40he
plus combi or maybe a high
recovery tank maybe with a shower coil
Central heating will be replaced as is very
old single pipe system

Totally confused and looking for advise please

done some flow timings :-

time taken to fill 5 litre container

20 secs = kitchen sink mains

30 secs = kitchen sink mains with
bathroom sink tap on full

17 secs = bath cold from header tank

23 secs = bath hot from cylinder

so, I am getting at least 15 litres / min
out of the kitchen mains tap and
10 litres / min with 2 taps fully open

I am used to a hot water flow of about
12 litres a min

does this mean that a combi with
16 litres/min flow will work ok ? and does
it also mean that a mains pressure cylinder
would also be ok ?

I would rather do without the expence
and aggro of replacing the service pipe

Regards Jeff

Replacing the service pipe is the ideal solution as it gives you more scope.
Also it is lead, so it NEEDS replacing. Forget what an architect says, they
know sweet nothing about water systems.

If the mains pipe is replaced and you get around 25-30 litres/min then
either:

1. Install a high flowrate combi.
Alpha CB50, W-B Greenstar 40kW, W-B Highflow, are ideal for you as you only
take showers most of the time. The likelihood of you running a shower and
drawing a bath is slim.

2. Install a Powermax. A "one box" floor standing solution run from the
mains. High flowrates.

3. A heat bank and separate condensing system boiler. High flowartes, and
will runs two showers no problem at all. and one shower and one bath at the
same time.

If the mains pipe stays at 15mm then:

1. An accumulator. This is a vessel with a large beachball inside which
acts a cushion. It charges up with water from the mains at the static
pressure. Static is when no water is drawn. Dynamic, or working, pressure,
is measured when the taps are on. You may have a high static pressure, but
the small pipe reduces dynamic pressure considerably. An accumulator stores
cold water and releases it at the static pressure with volume. Once the
pressure drops after use, it then charges itself back up from the mains
again.

It can be mated to an unvented cylinder. Cost is expensive. If you can get
the mains pipe sorted out, it would be much cheaper than the accumulator.
They are fine in poor flow water areas, like villages and end of lines.

2. A combi cylinder (combined cold tank and cylinder) heated by a combi.
The cylinder provides all the water in the house except the showers, which
the water section of the combi provides.




_________________________________________
Usenet Zone Free Binaries Usenet Server
More than 120,000 groups
Unlimited download
http://www.usenetzone.com to open account