I think a couple of people installed Heat Banks last year - what are your
views having run them for a while?

Can anyone explain the relative merits of heating the heatbank directly or
indirectly?
Why would I choose to make the primary circuit pressurised or vented?
Are there any other heatbank suppliers than DPS or Gledhill?

A while ago someone recommended the Worcester Greenstar(?) boiler, any more
good/bad reports?

DaveS

Dave wrote:
I think a couple of people installed Heat Banks last year - what are your
views having run them for a while?

Can anyone explain the relative merits of heating the heatbank directly or
indirectly?
Why would I choose to make the primary circuit pressurised or vented?
Are there any other heatbank suppliers than DPS or Gledhill?


I'm still not 100% clear on the diffence between a heatbank and a
thermal store. We have a Range thermal store, and it's very good. Boiler
(oil) fires for long, efficient runs, and radiators heat up very quickly
compared to conventional system.

Ours is heated directly (the water in the cylinder is circulated to the
boiler and back).


--
Grunff

"Grunff" wrote in message
...
Dave wrote:

I think a couple of people installed Heat Banks last year - what are
your
views having run them for a while?

Can anyone explain the relative merits of heating the heatbank directly
or
indirectly?
Why would I choose to make the primary circuit pressurised or vented?
Are there any other heatbank suppliers than DPS or Gledhill?

I'm still not 100% clear on the diffence
between a heatbank and a
thermal store.

Thermal store = immersed coil for DHW take off
Heat bank = an external high efficient plate heat exchanger. for DHW take
off.

Heat banks are more efficient and produce higher DHW flow rates.
Heat banks can be de-scaled very easily and resist scale more effectively.

We have a Range thermal store, and it's very good. Boiler
(oil) fires for long, efficient runs, and radiators heat up very quickly
compared to conventional system.

Ours is heated directly (the water in the cylinder is circulated to the
boiler and back).

IMM wrote:

Thermal store = immersed coil for DHW take off
Heat bank = an external high efficient plate heat exchanger. for DHW take
off.


Not much diff then, really. Ours has an immersed coil, but whether you
use it is optional. I didn't, preferring to use an external heat exchanger.

--
Grunff

"Dave" wrote in message
...

I think a couple of people installed Heat Banks last year - what are your
views having run them for a while?

Can anyone explain the relative merits
of heating the heatbank directly or
indirectly?

When direct "all" the boilers heat goes into the store. When indirect you
are relying on the efficiency of the coil.

Why would I choose to make the primary
circuit pressurised or vented?

In theory pressurised has little advantages over vented when using a heat
bank, as long as the system is fitted correctly and inhibitor is used and
replaced every 3-4 years. Pressurised does away with the F&E tank, in a heat
bank this can be integrated with the store.

Are there any other heatbank
suppliers than DPS or Gledhill?

Range cylinders:
http://www.range-cylinders.co.uk

The flowmax is a heat bank these days, although they say thermal store.

Many of the underfloor companies provide their own heat banks (usually made
to order from other companies)

A while ago someone recommended the Worcester Greenstar(?) boiler, any
more
good/bad reports?

So, far so good with these. Just make sure the system is cleaned before
installation and correct inhibitor used and replaced every 3 - 4 years.

Use an integrated heat bank, where the CH and DHW are off the store.

"Grunff" wrote in message
...
IMM wrote:

Thermal store = immersed coil for DHW take off
Heat bank = an external high efficient plate heat exchanger. for DHW
take
off.

Not much diff then, really.

Quiate a bigb difference.

Ours has an immersed coil, but whether you
use it is optional. I didn't, preferring to use
an external heat exchanger.

You should have used the coil as a pre-heat. Also this can be used for low
flowrates and the pump and plate come to supply the higher flowrates. This
prevents the pump cutting in when the tap is on for a second or two, which
is quite common.

Not much diff then, really. Ours has an immersed coil, but whether you
use it is optional. I didn't, preferring to use an external heat
exchanger.

Then you actually have a heat bank!

Christian.

"IMM" wrote in message
...

"Grunff" wrote in message
...
IMM wrote:

Thermal store = immersed coil for DHW take off
Heat bank = an external high efficient plate heat exchanger. for DHW
take
off.

Not much diff then, really.

Quiate a big difference.

Ours has an immersed coil, but whether you
use it is optional. I didn't, preferring to use
an external heat exchanger.

You should have used the coil as a pre-heat. Also this can be used for
low
flowrates and the pump and plate come to supply the higher flowrates. This
prevents the pump cutting in when the tap is on for a second or two, which
is quite common.

Another way is split the DHW and have the coil supply all outlets, except
the showers and baths where high flows are required, then the plate heayt
exchanger does that.

The coil has a pressure limit, so the coil supply would need a pressure
reducer before it and the cold supplies that are used for mixers also taken
after this reducer too.

The plates can go up to 10 barish, so no need for pressure reducers on this
leg for hot or cold and full power showers can be used, if the mains are man
enough.

Can anyone explain the relative merits of heating the heatbank directly or
indirectly?

Direct enables the full boiler output to be used. Also, you can have as many
direct heat sources and sinks (i.e. radiators) running off the heat bank,
like a huge Dunsley Neutraliser.

Indirect has the advantage that the controls are exactly the same as a
conventional system. It also allows sealed pressurised primary circuits.
This is good as it allows you a full choice of modern condensing boilers
(some of which can't run vented) and has all the benefits that go with
sealed operation (see the FAQ).

You can mix and match if desired. This would involve having a modern
condensing boiler on the indirect coil, whilst having your Aga, solar
heating and/or solid fuel boiler off the heat bank.

Radiators can be run off the heat bank (essential if you have even a
partially direct system) or off the boiler primary circuit, leaving the heat
bank solely for hot water heating.

A while ago someone recommended the Worcester Greenstar(?) boiler, any
more
good/bad reports?

I've had it almost a year now. Runs like a dream.

Christian.

Christian McArdle wrote:

Then you actually have a heat bank!


WooHooo!!

--
Grunff

"Christian McArdle" wrote in message
. net...
Can anyone explain the relative merits of heating the heatbank directly
or
indirectly?

Direct enables the full boiler output to be used. Also, you can have as
many
direct heat sources and sinks (i.e. radiators) running off the heat bank,
like a huge Dunsley Neutraliser.

Indirect has the advantage that the controls are exactly the same as a
conventional system. It also allows sealed pressurised primary circuits.
This is good as it allows you a full choice of modern condensing boilers
(some of which can't run vented) and has all the benefits that go with
sealed operation (see the FAQ).

All the top condensing boilers have vented versions: Worcester-Bosch,
Keston, Glow Worm, Ideal, etc. Combi boilers by nature are all pressurised,
but you would not use one of these with heat bank anyway.

On Wed, 1 Sep 2004 13:54:06 +0100, "IMM" wrote:


"Dave" wrote in message
...

I think a couple of people installed Heat Banks last year - what are your
views having run them for a while?

Can anyone explain the relative merits
of heating the heatbank directly or
indirectly?

When direct "all" the boilers heat goes into the store. When indirect you
are relying on the efficiency of the coil.

Why would I choose to make the primary
circuit pressurised or vented?

In theory pressurised has little advantages over vented when using a heat
bank, as long as the system is fitted correctly and inhibitor is used and
replaced every 3-4 years. Pressurised does away with the F&E tank, in a heat
bank this can be integrated with the store.


Also making the primary pressurised with a direct heatbank (i.e. the
bulk contents of the cylinder are pressurised) means that for Building
Regulations section G purposes it counts as a sealed storage system
and must therefore be installed by a certified installer.

Having the primary vented, whether with an integral F&E tank or not
means that this can be a DIY job, although is still subject to a
Building Notice because of part L1.

However, some boilers will not accept having an open vented primary,
so the choice then becomes making the heatbank a pressurised one
(professional installation) or having one with a coil on the input
side from the boiler (primary is pressurised) and the bulk water in
the heatbank being tertiary and open vented and separate from the
primary. This can be a DIY installation with Building Notice for
part L1.


..andy

To email, substitute .nospam with .gl

"Andy Hall" wrote in message
...
On Wed, 1 Sep 2004 13:54:06 +0100, "IMM" wrote:


"Dave" wrote in message
...

I think a couple of people installed Heat Banks last year - what are
your
views having run them for a while?

Can anyone explain the relative merits
of heating the heatbank directly or
indirectly?

When direct "all" the boilers heat goes into the store. When indirect
you
are relying on the efficiency of the coil.

Why would I choose to make the primary
circuit pressurised or vented?

In theory pressurised has little advantages over vented when using a heat
bank, as long as the system is fitted correctly and inhibitor is used and
replaced every 3-4 years. Pressurised does away with the F&E tank, in a
heat
bank this can be integrated with the store.


Also making the primary pressurised
with a direct heatbank (i.e. the
bulk contents of the cylinder are pressurised)
means that for Building
Regulations section G purposes it counts as a
sealed storage system and must therefore be
installed by a certified installer.

These are available, but rare and termed directly pressurised.

Having the primary vented, whether with an integral F&E tank or not
means that this can be a DIY job, although is still subject to a
Building Notice because of part L1.

However, some boilers will not accept
having an open vented primary,

Few and far between. There are plenty of state-of-the-art condensing boilers
that are vented.

so the choice then becomes making
the heatbank a pressurised one
(professional installation) or having one
with a coil on the input
side from the boiler (primary is pressurised)
and the bulk water in
the heatbank being tertiary and open vented
and separate from the primary. This can be
a DIY installation with Building Notice for
part L1.

"IMM" wrote in message
...

"Dave" wrote in message
...

I think a couple of people installed Heat Banks last year - what are
your
views having run them for a while?

Can anyone explain the relative merits
of heating the heatbank directly or
indirectly?

When direct "all" the boilers heat goes into the store. When indirect
you
are relying on the efficiency of the coil.

Oh another advantage of having the boiler direct is that boiler cycling can
be eliminated by using two cylinder stats. And there is no limit on the
size of the boiler. The larger the better. So, if a good deal is around on
a large boiler you can get it. Sometimes the difference between a large
output boiler and allow model is only a £100 or so. Well worth spending the
extra on a direct heat bank. Oversized boilers on an indirect coil will
cycle, as when on a normal rad circuit too.

On Wed, 1 Sep 2004 14:40:49 +0100, "IMM" wrote:


"Andy Hall" wrote in message
.. .
On Wed, 1 Sep 2004 13:54:06 +0100, "IMM" wrote:


"Dave" wrote in message
...

I think a couple of people installed Heat Banks last year - what are
your
views having run them for a while?

Can anyone explain the relative merits
of heating the heatbank directly or
indirectly?

When direct "all" the boilers heat goes into the store. When indirect
you
are relying on the efficiency of the coil.

Why would I choose to make the primary
circuit pressurised or vented?

In theory pressurised has little advantages over vented when using a heat
bank, as long as the system is fitted correctly and inhibitor is used and
replaced every 3-4 years. Pressurised does away with the F&E tank, in a
heat
bank this can be integrated with the store.


Also making the primary pressurised
with a direct heatbank (i.e. the
bulk contents of the cylinder are pressurised)
means that for Building
Regulations section G purposes it counts as a
sealed storage system and must therefore be
installed by a certified installer.

These are available, but rare and termed directly pressurised.

I wanted to make the point because there are direct heatbanks on the
market and it is not always immediately obvious that they are not
suitable for pressurised primary operation.




Having the primary vented, whether with an integral F&E tank or not
means that this can be a DIY job, although is still subject to a
Building Notice because of part L1.

However, some boilers will not accept
having an open vented primary,

Few and far between.

I've got one.


There are plenty of state-of-the-art condensing boilers
that are vented.

Of course, and there are quite a few around that won't accept open
venting. I simply raised the point so that it is not overlooked.



so the choice then becomes making
the heatbank a pressurised one
(professional installation) or having one
with a coil on the input
side from the boiler (primary is pressurised)
and the bulk water in
the heatbank being tertiary and open vented
and separate from the primary. This can be
a DIY installation with Building Notice for
part L1.


Another point here is that if a heatbank is direct and is using an
internal tank for the F&E, it muct be installed so that the tank is
above the highest radiator.
..andy

To email, substitute .nospam with .gl

"Andy Hall" wrote in message
news
On Wed, 1 Sep 2004 14:40:49 +0100, "IMM" wrote:


"Andy Hall" wrote in message
.. .
On Wed, 1 Sep 2004 13:54:06 +0100, "IMM" wrote:


"Dave" wrote in message
...

I think a couple of people installed Heat Banks last year - what are
your
views having run them for a while?

Can anyone explain the relative merits
of heating the heatbank directly or
indirectly?

When direct "all" the boilers heat goes into the store. When
indirect
you
are relying on the efficiency of the coil.

Why would I choose to make the primary
circuit pressurised or vented?

In theory pressurised has little advantages over vented when using a
heat
bank, as long as the system is fitted correctly and inhibitor is used
and
replaced every 3-4 years. Pressurised does away with the F&E tank, in
a
heat
bank this can be integrated with the store.


Also making the primary pressurised
with a direct heatbank (i.e. the
bulk contents of the cylinder are pressurised)
means that for Building
Regulations section G purposes it counts as a
sealed storage system and must therefore be
installed by a certified installer.

These are available, but rare and termed directly pressurised.

I wanted to make the point because there are direct heatbanks on the
market and it is not always immediately obvious that they are not
suitable for pressurised primary operation.

They are suitable.

Having the primary vented, whether with an integral F&E tank or not
means that this can be a DIY job, although is still subject to a
Building Notice because of part L1.

However, some boilers will not accept
having an open vented primary,

Few and far between.

I've got one.

You have not got a heat bank.

There are plenty of state-of-the-art condensing boilers
that are vented.

Of course, and there are quite a few around that won't accept open
venting. I simply raised the point so that it is not overlooked.

so the choice then becomes making
the heatbank a pressurised one
(professional installation) or having one
with a coil on the input
side from the boiler (primary is pressurised)
and the bulk water in
the heatbank being tertiary and open vented
and separate from the primary. This can be
a DIY installation with Building Notice for
part L1.

Another point here is that if a heatbank is direct and is using an
internal tank for the F&E, it muct be installed so that the tank is
above the highest radiator.

About the only constraint.

Another point here is that if a heatbank is direct and is using an
internal tank for the F&E, it muct be installed so that the tank is
above the highest radiator.

About the only constraint.

This can be quite a significant constraint, especially if a loft conversion
is envisaged at some point. However, it can be overcome by having a sealed
pressurised circuit for problem radiators (or even all of them) running off
a pumped plate heat exchanger off a direct heat bank loop.

Christian.

On Wed, 1 Sep 2004 15:47:49 +0100, "IMM" wrote:


"Andy Hall" wrote in message

Also making the primary pressurised
with a direct heatbank (i.e. the
bulk contents of the cylinder are pressurised)
means that for Building
Regulations section G purposes it counts as a
sealed storage system and must therefore be
installed by a certified installer.

These are available, but rare and termed directly pressurised.

I wanted to make the point because there are direct heatbanks on the
market and it is not always immediately obvious that they are not
suitable for pressurised primary operation.

They are suitable.

From the DPS site:

"GX units are only suitable for a vented boiler / heating systems with
a Feed & Expansion Tank."




Having the primary vented, whether with an integral F&E tank or not
means that this can be a DIY job, although is still subject to a
Building Notice because of part L1.

However, some boilers will not accept
having an open vented primary,

Few and far between.

I've got one.

You have not got a heat bank.

That's not the point. There are boilers around that are designed for
sealed system use. Vaillant ecoMAX is one example in addition to the
Micromat that I have,Viessmann is another.


There are plenty of state-of-the-art condensing boilers
that are vented.

Of course, and there are quite a few around that won't accept open
venting. I simply raised the point so that it is not overlooked.

so the choice then becomes making
the heatbank a pressurised one
(professional installation) or having one
with a coil on the input
side from the boiler (primary is pressurised)
and the bulk water in
the heatbank being tertiary and open vented
and separate from the primary. This can be
a DIY installation with Building Notice for
part L1.

Another point here is that if a heatbank is direct and is using an
internal tank for the F&E, it muct be installed so that the tank is
above the highest radiator.

About the only constraint.

True, but worth mentioning as people do sometimes install cylinders on
the ground floor.


..andy

To email, substitute .nospam with .gl

On Wed, 1 Sep 2004 15:53:54 +0100, "Christian McArdle"
wrote:

Another point here is that if a heatbank is direct and is using an
internal tank for the F&E, it muct be installed so that the tank is
above the highest radiator.

About the only constraint.

This can be quite a significant constraint, especially if a loft conversion
is envisaged at some point. However, it can be overcome by having a sealed
pressurised circuit for problem radiators (or even all of them) running off
a pumped plate heat exchanger off a direct heat bank loop.

Christian.


... or even from the primary circuit via a zone valve and heat
exchanger as I did for my workshop....

Needs another pump though.....


..andy

To email, substitute .nospam with .gl

From the DPS site:

"GX units are only suitable for a vented boiler / heating systems with
a Feed & Expansion Tank."

I've never seen a presurised heat bank advertised. You lose many of their
advantages by doing so. They would require much more expensive type
approval, too. Unpressurised heat banks can be used with pressurised central
heating systems with the use of additional heat exchangers and pumps (or
indirect coils). This is usually safer and more convenient.

Christian.

"Andy Hall" wrote in message
...
On Wed, 1 Sep 2004 15:47:49 +0100, "IMM" wrote:


"Andy Hall" wrote in message

Also making the primary pressurised
with a direct heatbank (i.e. the
bulk contents of the cylinder are pressurised)
means that for Building
Regulations section G purposes it counts as a
sealed storage system and must therefore be
installed by a certified installer.

These are available, but rare and termed directly pressurised.

I wanted to make the point because there are direct heatbanks on the
market and it is not always immediately obvious that they are not
suitable for pressurised primary operation.

They are suitable.

From the DPS site:

"GX units are only suitable for a vented boiler / heating systems with
a Feed & Expansion Tank."

You were on about the whole cylinder and primary circuit being pressurised.

Having the primary vented, whether with an integral F&E tank or not
means that this can be a DIY job, although is still subject to a
Building Notice because of part L1.

However, some boilers will not accept
having an open vented primary,

Few and far between.

I've got one.

You have not got a heat bank.

That's not the point.

You have NOT Got a heat bank.!

There are boilers around that are designed for
sealed system use. Vaillant ecoMAX is one example in addition to the
Micromat that I have,Viessmann is another.


You are confused.

There are plenty of state-of-the-art condensing boilers
that are vented.

Of course, and there are quite a few around that won't accept open
venting. I simply raised the point so that it is not overlooked.

so the choice then becomes making
the heatbank a pressurised one
(professional installation) or having one
with a coil on the input
side from the boiler (primary is pressurised)
and the bulk water in
the heatbank being tertiary and open vented
and separate from the primary. This can be
a DIY installation with Building Notice for
part L1.

Another point here is that if a heatbank is direct and is using an
internal tank for the F&E, it muct be installed so that the tank is
above the highest radiator.

About the only constraint.

True, but worth mentioning as people do sometimes install cylinders on
the ground floor.

On Wed, 1 Sep 2004 17:58:59 +0100, "IMM" wrote:


"Andy Hall" wrote in message
.. .
On Wed, 1 Sep 2004 15:47:49 +0100, "IMM" wrote:


"Andy Hall" wrote in message

Also making the primary pressurised
with a direct heatbank (i.e. the
bulk contents of the cylinder are pressurised)
means that for Building
Regulations section G purposes it counts as a
sealed storage system and must therefore be
installed by a certified installer.

These are available, but rare and termed directly pressurised.

I wanted to make the point because there are direct heatbanks on the
market and it is not always immediately obvious that they are not
suitable for pressurised primary operation.

They are suitable.

From the DPS site:

"GX units are only suitable for a vented boiler / heating systems with
a Feed & Expansion Tank."

You were on about the whole cylinder and primary circuit being pressurised.

Exactly, and this one is not suitable for that.

On the heat input side there are the following options

1) Heat bank with no coil, run directly using boiler primary water,
vented with integrated or loft F&E tank. Can be DIY.

2) Heat bank with no coil, run directly using boiler primary water,
unvented and pressurised to normal 3bar primary pressure. Needs
professional installation and heatbank cylinder able to take the
pressure.

3) Heat bank with plate heat exchanger on primary side and pump. Bulk
(tertiary) water in heatbank is vented (probably with integrated FE
tank) and separate pressurised (or vented) boiler primary. DIY install
with building notice.

4) As 3 but with coil on input side of heatbank with boiler primary
water (sealed or open vented) going through it (indirect). Not as
efficient as 3 but still a DIY job and doesn't need additional pump.


Having the primary vented, whether with an integral F&E tank or not
means that this can be a DIY job, although is still subject to a
Building Notice because of part L1.

However, some boilers will not accept
having an open vented primary,

Few and far between.

I've got one.

You have not got a heat bank.

That's not the point.

You have NOT Got a heat bank.!

That's irrelevant. You haven't got a hundred acres.



There are boilers around that are designed for
sealed system use. Vaillant ecoMAX is one example in addition to the
Micromat that I have,Viessmann is another.


You are confused.

I'm seldom confused and certainly not here.


..andy

To email, substitute .nospam with .gl

On Wed, 1 Sep 2004 17:13:05 +0100, "Christian McArdle"
wrote:

From the DPS site:

"GX units are only suitable for a vented boiler / heating systems with
a Feed & Expansion Tank."

I've never seen a presurised heat bank advertised. You lose many of their
advantages by doing so. They would require much more expensive type
approval, too. Unpressurised heat banks can be used with pressurised central
heating systems with the use of additional heat exchangers and pumps (or
indirect coils). This is usually safer and more convenient.

Christian.


Exactly, but would need a total of three pumps in the system.


..andy

To email, substitute .nospam with .gl

Thanks to all for the responses.
It looks like the answer is a Worcester Greenstar running vented into a
direct heatbank with a zone valve for the rads and a second zone valve for
the towel rails and airing cupboard rad. The boiler and cylinder (of
whichever type) will be in the garage so the F&E tank will need to be in the
loft and the DHW will need a return pipe to ensure hot water doesn't take
too long to reach the taps.

Any other comments?
Dave S

"Christian McArdle" wrote in message
. net...
From the DPS site:

"GX units are only suitable for a vented boiler / heating systems with
a Feed & Expansion Tank."

I've never seen a presurised heat
bank advertised.

They are available.

You lose many of their
advantages by doing so.

Not so. It depends on the application, such as having the boiler on the
ground floor and the boiler dumping "all" its heat.

"Andy Hall" wrote in message
...
On Wed, 1 Sep 2004 17:58:59 +0100, "IMM" wrote:


"Andy Hall" wrote in message
.. .
On Wed, 1 Sep 2004 15:47:49 +0100, "IMM" wrote:


"Andy Hall" wrote in message

Also making the primary pressurised
with a direct heatbank (i.e. the
bulk contents of the cylinder are pressurised)
means that for Building
Regulations section G purposes it counts as a
sealed storage system and must therefore be
installed by a certified installer.

These are available, but rare and termed directly pressurised.

I wanted to make the point because there are direct heatbanks on
the
market and it is not always immediately obvious that they are not
suitable for pressurised primary operation.

They are suitable.

From the DPS site:

"GX units are only suitable for a vented boiler / heating systems with
a Feed & Expansion Tank."

You were on about the whole cylinder and primary circuit being
pressurised.

Exactly, and this one is not suitable for that.

So?

Having the primary vented, whether with an integral F&E tank or
not
means that this can be a DIY job, although is still subject to a
Building Notice because of part L1.

However, some boilers will not accept
having an open vented primary,

Few and far between.

I've got one.

You have not got a heat bank.

That's not the point.

You have NOT Got a heat bank.!

That's irrelevant. You haven't got a hundred acres.

It does not change the fact that you haven't got a heat bank and you say you
have and say because you actually haven't it doesn't matter. You need
therapy

There are boilers around that are designed for
sealed system use. Vaillant ecoMAX is one example in addition to the
Micromat that I have,Viessmann is another.

You are confused.

I'm seldom confused and certainly not here.

Imagine your post on ripped paper and written in crayon and the scene is
set.

"Andy Hall" wrote in message
...
On Wed, 1 Sep 2004 17:13:05 +0100, "Christian McArdle"
wrote:

From the DPS site:

"GX units are only suitable for a vented boiler / heating systems with
a Feed & Expansion Tank."

I've never seen a presurised heat bank advertised. You lose many of their
advantages by doing so. They would require much more expensive type
approval, too. Unpressurised heat banks can be used with pressurised
central
heating systems with the use of additional heat exchangers and pumps (or
indirect coils). This is usually safer and more convenient.

Christian.

Exactly, but would need a total of three pumps in the system.

Are you saying pressurised heat banks don't exist?

"Dave" wrote in message
...
Thanks to all for the responses.
It looks like the answer is a Worcester Greenstar

Good choice.

running vented into a
direct heatbank

Sounds good.

with a zone
valve for the rads

Errm no. The rads taken off the heat bank using a pump and a check valve.

and a second zone valve for
the towel rails and airing cupboard rad.

Taken from where? The boiler primaries? Could be. Is there a need for the
zone valve when you want these on all year around? If off the boiler
primaries (flow and return) then the rails only operate when the bioler
does. If you want them on 24/7 then take then off the heat bank and use a
pump and check valve.

The boiler and cylinder (of
whichever type) will be in the garage
so the F&E tank will need to be in the
loft and the DHW will need a return pipe
to ensure hot water doesn't take
too long to reach the taps.

Can be done with a couple of check valves and DHW circulation pump.

Any other comments?

See above.

On Wed, 1 Sep 2004 22:49:17 +0100, "IMM" wrote:


"Dave" wrote in message
...
Thanks to all for the responses.
It looks like the answer is a Worcester Greenstar

Good choice.

running vented into a
direct heatbank

Sounds good.

with a zone
valve for the rads

One zone valve for the radiators and a second for the heatbank would
be the most appropriate, or a diverter valve.



Errm no. The rads taken off the heat bank using a pump and a check valve.

This is not the best way to connect the radiators. Apart from needing
an extra pump, it is not the most efficient way for the boiler to
work.

For the heatbank to be useful, it needs to operate at the highest
temperature possible in order to store the maximum amount of energy.
This is true throughout the year. The minimum useful flow
temperature to the heatbank is 75 degrees, with 82 being better.

For the condensing boiler to run most efficiently during the much
longer on times than the hot water requires, and accounting for the
lower heat output requirement during spring and autumn, the return
temperature needs to be as low as possible. The boiler will
automatically modulate down to achieve that and the flow temperature
can easily be below 50 and return below 40 degrees.
The efficiency of a condensing boiler increases markedly with reducing
return temperature and especially below the 54 degree dew point.

If you run the radiators from the heatbank, the flow temperature will
be that of the heatbank (i.e. 76-82 degrees). The boiler will come
on full periodically in order to replenish the heatbank and maintain
the required temperature. It has no real way of knowing the
difference between a DHW demand (a lot of heat for a short time) vs.
the CH (relatively little heat continuously).
Thus it will effectlively cycle on and off at around the ste point of
the heatbank, not at what the radiator load requires.

If a conventional boiler were being used, then this would be a
reasonable approach (because they are intended to run at a high single
temperature, but for a condensing one it isn't. It is far better to
connect the heat bank to the boiler and heat that rapidly at full
power and then switch the boiler to the radiators where it can detect
the heat load for the house directly and operate most efficiently



and a second zone valve for
the towel rails and airing cupboard rad.

Taken from where? The boiler primaries? Could be. Is there a need for the
zone valve when you want these on all year around? If off the boiler
primaries (flow and return) then the rails only operate when the bioler
does. If you want them on 24/7 then take then off the heat bank and use a
pump and check valve.

The boiler and cylinder (of
whichever type) will be in the garage
so the F&E tank will need to be in the
loft and the DHW will need a return pipe
to ensure hot water doesn't take
too long to reach the taps.

Can be done with a couple of check valves and DHW circulation pump.

Any other comments?

See above.


..andy

To email, substitute .nospam with .gl

On Wed, 1 Sep 2004 22:42:03 +0100, "IMM" wrote:


"Andy Hall" wrote in message
.. .
On Wed, 1 Sep 2004 17:13:05 +0100, "Christian McArdle"
wrote:

From the DPS site:

"GX units are only suitable for a vented boiler / heating systems with
a Feed & Expansion Tank."

I've never seen a presurised heat bank advertised. You lose many of their
advantages by doing so. They would require much more expensive type
approval, too. Unpressurised heat banks can be used with pressurised
central
heating systems with the use of additional heat exchangers and pumps (or
indirect coils). This is usually safer and more convenient.

Christian.

Exactly, but would need a total of three pumps in the system.

Are you saying pressurised heat banks don't exist?



No - simply that some are not suitable for pressurised operation, and
that if they are used pressurised that the regulations concerning
large volumes of pressurised water apply - must be installed
professionally.



..andy

To email, substitute .nospam with .gl

"Andy Hall" wrote in message
...
On Wed, 1 Sep 2004 22:49:17 +0100, "IMM" wrote:


"Dave" wrote in message
...
Thanks to all for the responses.
It looks like the answer is a Worcester Greenstar

Good choice.

running vented into a
direct heatbank

Sounds good.

with a zone
valve for the rads

One zone valve for the radiators
and a second for the heatbank would
be the most appropriate, or a diverter valve.

Located where?

Errm no. The rads taken off the heat bank using a pump and a check
valve.

This is not the best way to connect the radiators.

Oh my God. It is the best way.

Apart from needing
an extra pump, it is not the most
efficient way for the boiler to
work.

What the hell are you on about?

For the heatbank to be useful,
it needs to operate at the highest
temperature possible in order to
store the maximum amount of energy.
This is true throughout the year.
The minimum useful flow
temperature to the heatbank is 75 degrees,
with 82 being better.

You split the cylinder with a flow and return on the upper DHW section and a
flow and return on the lower heating section. The lower section can run at
a lower temp than the upper. Best use an outside weather compensator and
have the temp senor on the lower cylinder section. Both sections only need
a pump and check valve each from the boiler, with the DHW having priority.
The compensator will ensure the rad circuits will run at low temperatures
most of the time promoting condensing efficiency.

For the condensing boiler to run most
efficiently

snip

see above.

"Andy Hall" wrote in message
...
On Wed, 1 Sep 2004 22:42:03 +0100, "IMM" wrote:


"Andy Hall" wrote in message
.. .
On Wed, 1 Sep 2004 17:13:05 +0100, "Christian McArdle"
wrote:

From the DPS site:

"GX units are only suitable for a vented boiler / heating systems
with
a Feed & Expansion Tank."

I've never seen a presurised heat bank advertised. You lose many of
their
advantages by doing so. They would require much more expensive type
approval, too. Unpressurised heat banks can be used with pressurised
central
heating systems with the use of additional heat exchangers and pumps
(or
indirect coils). This is usually safer and more convenient.

Christian.

Exactly, but would need a total of three pumps in the system.

Are you saying pressurised heat banks don't exist?

No - simply that some are not suitable
for pressurised operation,

You should be certified. If they are pressurised heat banks then they are
suitable.

and that if they are used pressurised that the regulations concerning
large volumes of pressurised water apply - must be installed
professionally.

On Wed, 1 Sep 2004 22:40:49 +0100, "IMM" wrote:


"Andy Hall" wrote in message
.. .
On Wed, 1 Sep 2004 17:58:59 +0100, "IMM" wrote:


"Andy Hall" wrote in message


I wanted to make the point because there are direct heatbanks on
the
market and it is not always immediately obvious that they are not
suitable for pressurised primary operation.

They are suitable.

From the DPS site:

"GX units are only suitable for a vented boiler / heating systems with
a Feed & Expansion Tank."

You were on about the whole cylinder and primary circuit being
pressurised.

Exactly, and this one is not suitable for that.

So?

So the point is that there are some heatbanks that are not suitable
for pressurised operation. That was all.



Having the primary vented, whether with an integral F&E tank or
not
means that this can be a DIY job, although is still subject to a
Building Notice because of part L1.

However, some boilers will not accept
having an open vented primary,

Few and far between.

I've got one.

You have not got a heat bank.

That's not the point.

You have NOT Got a heat bank.!

That's irrelevant. You haven't got a hundred acres.

It does not change the fact that you haven't got a heat bank and you say you
have and say because you actually haven't it doesn't matter. You need
therapy

No, you need therapy. English lessons wouldn't hurt either.

I have never ever said that I have a heatbank. This does not,
however mean that I haven't studied how they work (in detail) and
haven't considered using one.

As I've told you on many occasions before, I don't have a good enough
mains flow, so there is no value in my having one versus a roof
storage tank and conventional cylinder. I am not short of space in
the loft or the airing cupboard so for me there is no value.

I don't need to actually *have* something to know how it works and the
most appropriate way to use it. This is not difficult stuff and
ownership does not alter physics.

It doesn't mean either that somebody with a good mains water supply or
who wants to redistribute space in their house won't derive benefit
from a heatbank - there are cases where they are useful as long as
they are appropriately connected.


There are boilers around that are designed for
sealed system use. Vaillant ecoMAX is one example in addition to the
Micromat that I have,Viessmann is another.

You are confused.

I'm seldom confused and certainly not here.

Imagine your post on ripped paper and written in crayon and the scene is
set.

Speak for yourself


..andy

To email, substitute .nospam with .gl

"Andy Hall" wrote in message
...
On Wed, 1 Sep 2004 22:40:49 +0100, "IMM" wrote:


"Andy Hall" wrote in message
.. .
On Wed, 1 Sep 2004 17:58:59 +0100, "IMM" wrote:


"Andy Hall" wrote in message


I wanted to make the point because there are direct heatbanks on
the
market and it is not always immediately obvious that they are
not
suitable for pressurised primary operation.

They are suitable.

From the DPS site:

"GX units are only suitable for a vented boiler / heating systems
with
a Feed & Expansion Tank."

You were on about the whole cylinder and primary circuit being
pressurised.

Exactly, and this one is not suitable for that.

So?

So the point is that there are some heatbanks that are not suitable
for pressurised operation. That was all.

If it is designed to be pressurised then it is suitable.

I have never ever said that I have a heatbank.

You did.

This does not,
however mean that I haven't studied how they work (in detail) and
haven't considered using one.

When you made your so called informed decision you didn't know enough.

Imagine your post on ripped paper and written in crayon and the scene is
set.

Andy Hall wrote:

It doesn't mean either that somebody with a good mains water supply or
who wants to redistribute space in their house won't derive benefit
from a heatbank - there are cases where they are useful as long as
they are appropriately connected.

Quite - we have pretty poor mains pressure (just under a bar - the
reservoir is about 12m above the house), and no real space problems. The
reason I put in the thermal store (or heatbank as it seems to be defined
here) was becuse the oil boiler was short cycling, despite all my
attempts to cure it. The thermal store solved this, and provided us with
a nice on demand energy store.

--
Grunff

"Grunff" wrote in message
...
Andy Hall wrote:

It doesn't mean either that somebody with a good mains water supply or
who wants to redistribute space in their house won't derive benefit
from a heatbank - there are cases where they are useful as long as
they are appropriately connected.

Quite - we have pretty poor mains pressure (just under a bar - the
reservoir is about 12m above the house), and no real space problems. The
reason I put in the thermal store (or heatbank as it seems to be defined
here)

There is a difference.

was becuse the oil boiler was short cycling, despite all my
attempts to cure it. The thermal store solved this, and provided us with
a nice on demand energy store.

It is possible to use them with a cold water storage tank and a bronze pump
to boost water pressure. Then no boiler short cycling if two cylinder stats
are fitted. It is also possible to use a smaller boiler using a heat bank.

On Thu, 2 Sep 2004 00:24:06 +0100, "IMM" wrote:


"Andy Hall" wrote in message
.. .
On Wed, 1 Sep 2004 22:49:17 +0100, "IMM" wrote:


"Dave" wrote in message
...
Thanks to all for the responses.
It looks like the answer is a Worcester Greenstar

Good choice.

running vented into a
direct heatbank

Sounds good.

with a zone
valve for the rads

One zone valve for the radiators
and a second for the heatbank would
be the most appropriate, or a diverter valve.

Located where?

On the boiler flow with one zone or diverted branch going to the
heatbank and the other to the radiators.




Errm no. The rads taken off the heat bank using a pump and a check
valve.

This is not the best way to connect the radiators.

Oh my God.

How can I help you?

It is the best way.

Not for a condensing boiler.



Apart from needing
an extra pump, it is not the most
efficient way for the boiler to
work.

What the hell are you on about?

To circulate the water from the heatbank through the radiators and
back requires a pump unless you use the one used for the DHW heat
exchanger and zone or diverter valves.




For the heatbank to be useful,
it needs to operate at the highest
temperature possible in order to
store the maximum amount of energy.
This is true throughout the year.
The minimum useful flow
temperature to the heatbank is 75 degrees,
with 82 being better.

You split the cylinder with a flow and return on the upper DHW section and a
flow and return on the lower heating section. The lower section can run at
a lower temp than the upper.

You mean two separate flows and returns from the boiler?
That would mean more complexity and the boiler is still unable to
properly detect the heat load of the radiators, because the heatbank
is still in the middle.

If you meant on the radiator connections, there is no value in having
a reduced temperature flow and return to the radiators if the boiler
is connected to the top and bottom of the heatbank. That simply
reduces the rate of heat delivery to the radiators for a given water
flow. It won't alter what the boiler sees, other than a reduced rate
of energy use. To feed the heatbank it still has to attempt to meet
the storage temperature.

Best use an outside weather compensator and
have the temp senor on the lower cylinder section. Both sections only need
a pump and check valve each from the boiler, with the DHW having priority.

The outside temperature sensor is simply another control term for the
boiler when used for space heating. It doesn't alter the behaviour of
the heat bank load which will effectively damp the detection that the
boiler would have had of the return temperature directly from the
radiators.


The compensator will ensure the rad circuits will run at low temperatures
most of the time promoting condensing efficiency.

It isn't the operating temperature of the radiators that matters,
it's what the boiler can see. Having a large energy store in the
way, screws up the control that is intended for a condensing boiler -
i.e. to see the heating load and modulate finely..

This is why the heat bank should be used as an energy store for the
hot water and not to run the radiators when a condensing boiler is the
main or only heat source.






For the condensing boiler to run most
efficiently

snip

see above.



..andy

To email, substitute .nospam with .gl

On Thu, 2 Sep 2004 00:27:01 +0100, "IMM" wrote:



Are you saying pressurised heat banks don't exist?

No - simply that some are not suitable
for pressurised operation,

You should be certified. If they are pressurised heat banks then they are
suitable.

What are you talking about? I clearly and consistently made the
point that some heat banks are unsuitable for pressurised operation.

Logically that means that some are.

The point was that one should check before buying if pressurised
operation is being considered.

Have you always been this obtuse or is it an acquired skill?


..andy

To email, substitute .nospam with .gl

On Thu, 2 Sep 2004 00:32:44 +0100, "IMM" wrote:


"Andy Hall" wrote in message


So the point is that there are some heatbanks that are not suitable
for pressurised operation. That was all.

If it is designed to be pressurised then it is suitable.

No ****, Sherlock.


I have never ever said that I have a heatbank.

You did.

Please provide the post where I have.



This does not,
however mean that I haven't studied how they work (in detail) and
haven't considered using one.

When you made your so called informed decision you didn't know enough.


I knew and know precisely what was required. In order to improve the
mains supply to make a mains pressure DHW system interesting would
have cost about £5k. I have better places to spend that kind of
money, especially when I can achieve what I want in different ways.

All of which is completely irrelevant anyway, because we are not
discussing my application.



..andy

To email, substitute .nospam with .gl

On Thu, 02 Sep 2004 00:43:45 +0100, Grunff wrote:

Andy Hall wrote:

It doesn't mean either that somebody with a good mains water supply or
who wants to redistribute space in their house won't derive benefit
from a heatbank - there are cases where they are useful as long as
they are appropriately connected.

Quite - we have pretty poor mains pressure (just under a bar - the
reservoir is about 12m above the house), and no real space problems. The
reason I put in the thermal store (or heatbank as it seems to be defined
here) was becuse the oil boiler was short cycling, despite all my
attempts to cure it. The thermal store solved this, and provided us with
a nice on demand energy store.

That's a good reason. Presumably the boiler has a large thermal mass
and quite high non-modulated output and the previous cylinder was
unable to take what it could deliver.

In this instance, a heatbank is ideal because it can swallow all the
output.



..andy

To email, substitute .nospam with .gl