"John Aston" wrote in message
.. .
IMM wrote in message
...
I assume you haven't bought any equipment yet.
That's correct.
In your situation which I
assume you have 1 bath and two showers, and I would go:
1. Combi boiler (to do the two showers only)
2. A "combination" cylinder with quick recovery coil. (cold tank and
hot
cylinder all in one space saving unit). This operates at low pressure
http://www.rcmgroup.co.uk/specialized.htm RCM will make a large cold
tank
section for you. They will ake the hot and cold section sizes to
order.
The CH side of the combi acts as a normal system boiler heating the
cylinder
and CH. The cylinder does the bath and therest of the house to give
good
fillups. The water side of the combi only does high pressure showers.
Something like an Alpha CB50, W-B Greenstar high flow condensing combi
would
do. The W-B Greenstar 40kW model can deliver 16 litres/min and you need
to
add cold to the showers, so a decent shower had if two on at the same
time.
This approach is cost effective and no power shower pump used.
Sorry, I'm misunderstanding something here. I thought that the total flow
rate was limited by the available flow rate at the incoming service pipe.
Or
is hot water stored in the combi boiler and pumped to the shower on
demand?
Apologies for my ignorance.
Stored water in the combination cylinder for all the house giving a good
flow, which is not on the mains. The combi cylinder is the bottom right.
http://www.rcmgroup.co.uk/specialized.htm
The mains only supplying the two showers via the combi boiler giving high
pressure showers with a power shower pump. The Alpha CB50 is a stored water
combi, the Greenstar is not.
Will you really have the bath filling and a shower
on at the same time? A relative has had a single
shower power shower pump serving two showers for
10 years. Not once has two showers been on at the same time.
I would like to budget for a bath and shower that are
on simultaneously. I have a large family.
That is fine. Some people tend to oversize water systems. If one bath and
one shower simultaneously then the combination cylinder with a quick
recovery coil and a combi boiler doing only the showers is the way. I assume
the bath will be below or on the same level as the cylinder? If so, then no
problems.