Hello group,

I'm researching a replacement hot water cylinder as an upgrade / replacement
for the existing aging one.
The current one is roughly 1m high and 400mm wide.

Current config is gravity circulated from bolier on 28mm pipework, no HW
thermostat.

This works OK, but water takes ages to heat, and often isn't quite enough,
hence upgrade.

Plan is to replace with a fast recovery cylinder and convert system to fully
pumped at the same time. Pump is currently situated near boiler, and a "T"
downstream to send water to upstairs / downstairs circuits.

I'd like to change to upstairs / downstairs zones also, so shopping list
will include suitable motorised valves to allow this.

Bolier is a Baxi back-boiler about 5 years old, so no plans to replace this.
Programmer is of similar age and has facility to control valves etc. House
currently has 1 thermostat in downstairs hall, all rads have TRVs apart from
hall and bathroom.

I've looked at the "Superduty" cylinder offerings from Albion:
http://www.albion-online.co.uk/Superduty.html

Is there and other makes / models you can recommend? Any other things I need
to consider or buy to do this?

Many thanks,

Alan.

On Mon, 10 Apr 2006 14:34:27 GMT someone who may be "Alan"
wrote this:-

Plan is to replace with a fast recovery cylinder and convert system to fully
pumped at the same time. Pump is currently situated near boiler, and a "T"
downstream to send water to upstairs / downstairs circuits.

If your house is suitable for solar heating (southish facing roof
for example) then you may want to consider fitting a solar ready
cylinder. The price of sunshine is not going to change, unlike that
of gas and it should provide most of your hot water in the summer
and a substantial contribution for much of the year. One supplier is
http://www.imaginationsolar.com/hwcyl.htm

I'd like to change to upstairs / downstairs zones also, so shopping list
will include suitable motorised valves to allow this.

Bolier is a Baxi back-boiler about 5 years old, so no plans to replace this.
Programmer is of similar age and has facility to control valves etc. House
currently has 1 thermostat in downstairs hall, all rads have TRVs apart from
hall and bathroom.

Three zone valves and a little pipework re-arrangement then.
Presumably you want all the heating on all the time, with each zone
just controlled by its thermostat. An alternative would be a three
channel controller so you could have the upstairs and downstairs
heating on at different times.

Check how the boiler is fed and vented. This is often with via the
pipes to the hot water cylinder, which are teed off at the cylinder
and then continue to the loft.


--
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

In article ,
"Alan" writes:
Plan is to replace with a fast recovery cylinder and convert system to fully
pumped at the same time. Pump is currently situated near boiler, and a "T"
downstream to send water to upstairs / downstairs circuits.

Bolier is a Baxi back-boiler about 5 years old, so no plans to replace this.

I think you'll have problems here due to gross mis-match
of the power of the two items. Your back boiler is probably
something like 6-8kW output, and a fast recovery cylinder can
probably take at least 25kW. This means that when run from such
an under powered boiler, the return temperature will be very
low, and will force the boiler into condensing mode, which
could quickly wreck a conversional boiler.

I would suggest only using a fast recovery cylinder with a
condensing boiler, and stick to a regular Part L cylinder if
you have a convensional boiler, which requires a return water
temperature of at least 60C to avoid condensing.

--
Andrew Gabriel

"Andrew Gabriel" wrote in message
...
In article ,
"Alan" writes:
Plan is to replace with a fast recovery cylinder and convert system to
fully
pumped at the same time. Pump is currently situated near boiler, and a
"T"
downstream to send water to upstairs / downstairs circuits.

Bolier is a Baxi back-boiler about 5 years old, so no plans to replace
this.

I think you'll have problems here due to gross mis-match
of the power of the two items. Your back boiler is probably
something like 6-8kW output, and a fast recovery cylinder can
probably take at least 25kW. This means that when run from such
an under powered boiler, the return temperature will be very
low, and will force the boiler into condensing mode, which
could quickly wreck a conversional boiler.

I would suggest only using a fast recovery cylinder with a
condensing boiler, and stick to a regular Part L cylinder if
you have a convensional boiler, which requires a return water
temperature of at least 60C to avoid condensing.

--
Andrew Gabrie

Andrew - good point, I'll check the power output. So returning water which
is vastly lower in temperature to the output of the boiler can / will cause
condensing where it's not wanted, as it's not a condensing boiler? I hadn't
considered this.
Plan "B" would be a regular cylinder as you say, but still go fully pumped
and zoned then.

David's suggestion a solar ready cylinder is interesting - I'll research
this option also.

Alan.

"Alan" wrote in
:


I think you'll have problems here due to gross mis-match
of the power of the two items. Your back boiler is probably
something like 6-8kW output, and a fast recovery cylinder can
probably take at least 25kW.

My slightly older Baxi Bermuda comes in 2 flavours, 57/3 with a max o/p of
21 kW, and the 45/3 with a max o/p of 16.5 kW

I would suggest only using a fast recovery cylinder with a
condensing boiler,

I use it with a Superduty CF80, and it works fine.

I've never checked the return temperature, as it's only on for 2 spasms a
day, but it runs good and hot.

mike

"Andrew Gabriel" wrote in message
...
In article ,
"Alan" writes:
Plan is to replace with a fast recovery cylinder and convert system to
fully
pumped at the same time. Pump is currently situated near boiler, and a
"T"
downstream to send water to upstairs / downstairs circuits.

Bolier is a Baxi back-boiler about 5 years old, so no plans to replace
this.

I think you'll have problems here due to gross mis-match
of the power of the two items. Your back boiler is probably
something like 6-8kW output, and a fast recovery cylinder can
probably take at least 25kW. This means that when run from such
an under powered boiler, the return temperature will be very
low, and will force the boiler into condensing mode, which
could quickly wreck a conversional boiler.

I would suggest only using a fast recovery cylinder with a
condensing boiler, and stick to a regular Part L cylinder if
you have a convensional boiler, which requires a return water
temperature of at least 60C to avoid condensing.

A fast recovery cylinder greatly reduces inefficient boiler cycling. Worth
fitting and setting up the temp differential across the flow/return to the
max the makers say. Most will go to 15C on non-condensing boilers.

Andrew - good point, I'll check the power output.

OK, bolier output is 14.65 kw - so should be OK, similar to Mike's setup.

I've investigated the dual-coil solar cylinders, and am more likely to go
this route now for future solar heating. The tanks have 60mm insulation vs
~22mm on standard ones which will help retain heat no matter what the heat
source is.

Alan.

In article ,
"Alan Deane" writes:

Andrew - good point, I'll check the power output.

OK, bolier output is 14.65 kw - so should be OK, similar to Mike's setup.

OK, I've only limited experience of back boilers, and it
was only 7kW -- I didn't realise they were available at
significantly higher outputs.

--
Andrew Gabriel