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  #1   Report Post  
Tim
 
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Default Thermal store cycliners - which one/any good?

Hi

*** Preamble ************************************************** *****

The ongoing wibblings of moving my family in with Dad... [Dad's house is a
3 bedroom bungalow with roof converstion fitted with "evolved" CH, but new
boiler - vented type]

As some of the radiator pipework is poorly run (miles of 10mm supplying 2
large double panel rads :-( ) and there's much weirdness in the plumbing
due to previous add-ons and random work, I'm going to replace a fair bit
of the CH copper.

So, I thought I might as well consider a thermal store cylinder at the
same time. Good excuse to have the old cylinder out and rationalise all
the odd pipework round the back.

This solves the problem of insufficient hot water pressure upstairs
and gets rid of a massive tank in a little room that could be used as
decent storage space.

Disclaimer - I've done some basic plumbing on occasion but I'm not upto
date with modern practises.

*** Actual research and questions ************************************

Seems like a generally good idea to go for a thermal store system. His
incoming mains water pipe was changed recently back to the road to the
blue plastic stuff.

Q: would that imply it's 25mm? Looks fairly chunky.

And, Dad already changed the copper that meets this and feeds into the
house on the first leg to 22mm. And the mains water pressure is mentally
high - though I have yet to take a dynamic pressure reading. So I think
the house meets the criteria for such a system.

Q: But - which one? I've been all over the web and found:

McDonald Engineers' ThermFlow - simple cylinder, use 2 external pumps (boiler
primary and CH)

Gledhill BoilerMate2000/SysteMate2000 (can't work out what the difference
is yet - possible one is direct and the other indirect??) Very poncy
design with microprocessor control, 3 pumps (why there's a pump on the
mains water circuit I don't know) and lots of sensors to go wrong. Looks
pretty though. Expensive at 1200 squids up, but does include the controler
and all the pumps in a nice neat housing.

Heatweb - Also looks complicated like the Gledhill, but not as neat.

Albion - simple again, like the McDonalds'.

Q: Would I want direct or indirect? Direct seems simpler - pump the boiler
primary through the bulk of the tank and the rads.

*** Final and the ultimate question ***********************************

So - from people that fitted thermal store cylinders: are they any good
and which one did you use? Any general theories/opinions also most welcome
:-)

Ta very muchly.
Timbo

--
Tim Southerwood

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Grunff
 
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Tim wrote:

Q: would that imply it's 25mm? Looks fairly chunky.


Probably, could be 32mm.


Q: But - which one? I've been all over the web and found:


I have a range 210l thermal store (but used with a plate exchanger, so
I'm told that makes it a heatbank ;-). It's very good. I'm very happy,
and would buy another one.


Q: Would I want direct or indirect? Direct seems simpler - pump the boiler
primary through the bulk of the tank and the rads.


I have direct, and it works very well with our oil boiler.


So - from people that fitted thermal store cylinders: are they any good
and which one did you use? Any general theories/opinions also most welcome
:-)


Yes, I think they're great. The large stored capacity means long burn
times for the boiler, all the hot water you want, and immediate heating
up of the house when the CH kicks in.


--
Grunff
  #3   Report Post  
Christian McArdle
 
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Q: Would I want direct or indirect? Direct seems simpler - pump the boiler
primary through the bulk of the tank and the rads.


It has significant advantages and disadvantages. The main advantage is that
it allows the boiler to reheat the store in a very efficient manner, dumping
its full load into the cylinder, rather than relying on an indirect coil
that might not be able to transfer as much heat. This is particularly useful
if you are running radiators off the store. It also allows the boiler to use
a lower flow temperature (good for condensing) as there is no need to
provide a temperature differential that a heat exchanger would require. You
can run the boiler at 75C, rather than 82-85C.

The main disadvantage is that it doesn't allow sealed pressurised operation
of the boiler, a system which has a number of advantages, such as leak
detection and protection, pump over prevention, easier filling & flushing,
allowing radiators high up, etc.

So - from people that fitted thermal store cylinders: are they any good
and which one did you use? Any general theories/opinions also most welcome
:-)


I have a DPS Pandora heat bank (you refer to these as the "heatweb"). It is
an indirect type, as there are likely to be radiators as the highest point
in the system, so I wanted sealed pressurised operation. The rads are off
the boiler primary, not from the heat bank.

It is absolutely excellent and works entirely as described. It has been
fitted for over a year and I still haven't had to top it up (manual fill
version). I believe the Gledhill may be technically superior to the model I
have. In particular, it is my understanding that the Gledhill varies pump
speed to maintain heat bank stratification. However, I haven't in practice
found destratification to be a problem as the system never really runs out
of hot water.

The biggest test was filling a 750 litre birthing pool to 40C. It managed
this in just over 40 minutes, although the outlet temperature did drop to
about the required 40C by the time it had completed.

In conclusion, I would definitely fit this type of system again. Although my
parent's Megaflo also provides excellent performance, I prefer the easy
maintenance of the heat bank.

BTW, I'd avoid the traditional thermal store type devices. I would only
choose a model with a plate heat exchanger for DHW operation.

Christian.


  #4   Report Post  
Tim
 
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Hi Christian,

Thanks for your reply.

On Tue, 02 Nov 2004 15:10:08 +0000, Christian McArdle wrote:

Q: Would I want direct or indirect? Direct seems simpler - pump the boiler
primary through the bulk of the tank and the rads.


It has significant advantages and disadvantages. The main advantage is that
it allows the boiler to reheat the store in a very efficient manner, dumping
its full load into the cylinder, rather than relying on an indirect coil
that might not be able to transfer as much heat.


That seems a clear choice then, for me (see below).

This is particularly useful
if you are running radiators off the store. It also allows the boiler to use
a lower flow temperature (good for condensing) as there is no need to
provide a temperature differential that a heat exchanger would require. You
can run the boiler at 75C, rather than 82-85C.


Longer life for the boiler...

The main disadvantage is that it doesn't allow sealed pressurised operation
of the boiler, a system which has a number of advantages, such as leak
detection and protection, pump over prevention, easier filling & flushing,
allowing radiators high up, etc.


Shouldn't be a problem. Only got rads on 2 floors, with the cylider on the
lower floor - I assume that will be OK?

So - from people that fitted thermal store cylinders: are they any good
and which one did you use? Any general theories/opinions also most welcome
:-)


I have a DPS Pandora heat bank (you refer to these as the "heatweb"). It is
an indirect type, as there are likely to be radiators as the highest point
in the system, so I wanted sealed pressurised operation. The rads are off
the boiler primary, not from the heat bank.


Ah yes - Heatweb stuck in my mind, but they do sell different things - yes
it was the Pandora.

I can't make up my mind whether to take the rads off the primary via a 3
way valve or use the heat store to feed them. I suppose that using the
heat store will guarantee long boiler burns. But is there a danger that
the radiators will deplete the heat from the store? Some pictures indicate
that the radiator feed is taken off the lower half of the cylinder, so I
presume not??

Was there any particular reason you fed the rads directly from the primary?

It is absolutely excellent and works entirely as described.

snip

Hmm - this idea sounds better than ever :-)

The biggest test was filling a 750 litre birthing pool to 40C. It managed
this in just over 40 minutes, although the outlet temperature did drop to
about the required 40C by the time it had completed.


Wow. I don't think that I've had a CH HW system that could run for 40 minutes
without going stone cold after 20.

BTW, I'd avoid the traditional thermal store type devices. I would only
choose a model with a plate heat exchanger for DHW operation.


Ah - I did see "heat plate" mentioned.

Thank you very much.

Timbo
  #5   Report Post  
Tim
 
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On Tue, 02 Nov 2004 15:10:08 +0000, Christian McArdle wrote:

I have a DPS Pandora heat bank (you refer to these as the "heatweb"). It
is an indirect type, as there are likely to be radiators as the highest
point in the system, so I wanted sealed pressurised operation. The rads
are off the boiler primary, not from the heat bank.


Hi again

Follow on question:

Did you use any particularly special controller? I presume one could use a
basic timeswitch/room thermostat combo (or zoned set thereof) doing the CH
rad pump (and zone valves), with a thermostat on the thermal store doing
the boiler control? And couple the primary circuit pump to the boiler
control**

** The Gledhill does make special mention of running the pump on for some
minutes after the boiler cuts out to be nice to the boiler.

Ta,

Timbo

--
Tim Southerwood



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Tim
 
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Thanks very much indeed, Grunff.

On Tue, 02 Nov 2004 15:01:53 +0000, Grunff wrote:

Tim wrote:

Q: would that imply it's 25mm? Looks fairly chunky.


Probably, could be 32mm.


Flow shouldn't be a problem then :-)

Q: But - which one? I've been all over the web and found:


I have a range 210l thermal store (but used with a plate exchanger, so
I'm told that makes it a heatbank ;-). It's very good. I'm very happy,
and would buy another one.


Sounds good. Which type is it - also Pandora? I hadn't yet come across the
idea of using an external heat plate exchanger until now...


Q: Would I want direct or indirect? Direct seems simpler - pump the boiler
primary through the bulk of the tank and the rads.


I have direct, and it works very well with our oil boiler.


OK.


So - from people that fitted thermal store cylinders: are they any good
and which one did you use? Any general theories/opinions also most welcome
:-)


Yes, I think they're great. The large stored capacity means long burn
times for the boiler, all the hot water you want, and immediate heating
up of the house when the CH kicks in.


I was sort of convinced before (but worried that it might be a "fad"
product), but now that people say thay actually work I'm strongly
convinced that this is the way to go.

Half expecting someone to suggest I fit a combi instead! ;-/

Many thanks

Tim...
  #7   Report Post  
Christian McArdle
 
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Shouldn't be a problem. Only got rads on 2 floors, with the cylider on the
lower floor - I assume that will be OK?


Yes, but you must specify a model that can be topped up from a roof tank and
be vented in the conventional way. The specific DPS Pandora I have wouldn't
work, as it requires to be the highest point in the system. This wasn't a
problem for me, as I'm not running radiators through it, so it is the only
point in the system...

Christian.



  #8   Report Post  
Christian McArdle
 
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Was there any particular reason you fed the rads directly from the
primary?

Yes, the radiators are (or will be when I convert the loft) the highest
point in the system. This means that they require a sealed pressurised
system. It is actually possible to have a sealed pressurised system fed from
the heat bank, but this requires 2 additional pumps and an additional plate
heat exchanger. The boiler and cylinder are already in the loft and I didn't
want additional tanks above, even if they could have been accommodated
somehow.

Christian.




  #9   Report Post  
Tim
 
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Oops - one more poser... Sorry.

I mentioned a while back (not that anyone would be expected to remember)
that I was possibly going to use wet underfloor heating in a conservatory
(modern B/Regs aside...)

Now, I'd want a lower water temperature for that (at least not 70+).

Is there a good way I can work this into the design at this stage without
going to the lengths of using some sort of mixer system?

I can't obviously see one - but I've just discovered since reading various
replies that I still don't know half of the options available with thermal
store systems. Everytime I read up on the web, there's another product
with a slightly differnt way of doing things.

Ta muchly.

Timbo
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Tim
 
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On Tue, 02 Nov 2004 16:10:39 +0000, Christian McArdle wrote:

Was there any particular reason you fed the rads directly from the

primary?

Yes, the radiators are (or will be when I convert the loft) the highest
point in the system. This means that they require a sealed pressurised
system. It is actually possible to have a " fed from the heat bank, but
this requires 2 additional pumps and an additional plate heat exchanger.
The boiler and cylinder are already in the loft and I didn't want
additional tanks above, even if they could have been accommodated
somehow.


OK... Sorry for being thick: The header tank's already in the roof and
it's staying there (3 ft above the highest rad).

I'd assumed that the thermal store water + boiler primary were generally
pressuried by the header tank (though I did notice that your Pandora is
locally filled through a little plug in the top of the cylinder, which I
hadn't expected?)

In other words, I though that the termal store system wasn't dissimilar to
the way that a conventional HW cylinder is pressurised by the CW tank in
the loft. So I hadn't actually foreseen a problem, as long as the rads
were below the header tank level.

Is this an area which thermal stores vary a lot in, and does "sealed
pressurised system" mean "fed from a header tank in the loft"?

Sorry again for sounding like a bit of a plank. :/

Timbo


  #11   Report Post  
Grunff
 
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Tim wrote:

Sounds good. Which type is it - also Pandora? I hadn't yet come across the
idea of using an external heat plate exchanger until now...


I don't actually know - it came from Range, as did the flow switch which
drives it.


I was sort of convinced before (but worried that it might be a "fad"
product), but now that people say thay actually work I'm strongly
convinced that this is the way to go.

Half expecting someone to suggest I fit a combi instead! ;-/


Two combis - you always need two.



--
Grunff
  #12   Report Post  
Christian McArdle
 
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Did you use any particularly special controller? I presume one could use a
basic timeswitch/room thermostat combo (or zoned set thereof) doing the CH
rad pump (and zone valves), with a thermostat on the thermal store doing
the boiler control? And couple the primary circuit pump to the boiler
control**


No, my system is bog standard S-Plan-Plus off the boiler. Standard 2 channel
programmer, with both CH and HW to always on. 4 zones, 3 heating (to be
expanded to 5) and 1 for the heat bank. All heating zones have programmable
thermostats.

Had I run the radiators through the heatbank, I would have used a slightly
unusual control system, due to the radiator positioning requirements I have.
Basically, I would have a second plate exchanger pumped loop. The other side
of this exchanger would have been a sealed pressurised circuit, subdivided
using S-Plan-Plus zone valve, pump and controls to the radiator zones. This
gives the advantage of limited leakage, leakage detection, high mounted
radiators and pressure fill, which might as well be used downstairs and well
as in the loft conversion.

The gravity primary circuit would then only be used within the heat bank,
the DHW and CH plate exchanger loops and the boiler (although indirect would
also work, assuming a coil that matches the boiler's output).

Christian.



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Christian McArdle
 
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Half expecting someone to suggest I fit a combi instead! ;-/

Two combis - you always need two.


Or 2 multipoint heaters instead.

Christian.


  #14   Report Post  
Christian McArdle
 
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Had I run the radiators through the heatbank, I would have used a slightly
unusual control system, due to the radiator positioning requirements I

have.

Note also that it is worth connecting up 2 vertically separated cylinder
thermostats to create a very high hysterysis network. This way, you get long
efficient burns and keep the primary cold most of the time, avoiding losses
there.

Christian.



  #15   Report Post  
Christian McArdle
 
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In other words, I though that the termal store system wasn't dissimilar to
the way that a conventional HW cylinder is pressurised by the CW tank in
the loft. So I hadn't actually foreseen a problem, as long as the rads
were below the header tank level.


Yes, and you would need to use a similar system in your setup.

However, in certain circumstances (such as mine), you can take advantage of
the fact that the water goes nowhere to remove the expense, space and
inconvenience of having the header tank. In your case, I don't think you can
and you need a conventional vented tank arrangement.

Is this an area which thermal stores vary a lot in, and does "sealed
pressurised system" mean "fed from a header tank in the loft"?


No, it means a sealed circuit with no vent, filled from a hose from the
mains, with a pressure gauge, pressure relief valve and expansion pressure
vessel. There is no need for there to be a boiler in circuit to have one.
You can run a sealed pressurised circuit from the heat bank, with an
additional heat exchanger, but it adds to complexity.

Christian.





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Christian McArdle
 
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Is there a good way I can work this into the design at this stage without
going to the lengths of using some sort of mixer system?


Nah. Put it a mixer system. You need fine specific temperature control for
that application. You might get away with putting the mixer (and pump) near
the heat bank (presumably in some sort of airing cupboard), rather than
trying to find space near the floor in question, although with all these
circuits, pumps, valves etc., it's going to look like the engines of the
space shuttle before long. Make sure you document what all the bits do!

Christian.


  #17   Report Post  
Tim
 
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On Tue, 02 Nov 2004 16:29:29 +0000, Christian McArdle wrote:

In other words, I though that the termal store system wasn't dissimilar to
the way that a conventional HW cylinder is pressurised by the CW tank in
the loft. So I hadn't actually foreseen a problem, as long as the rads
were below the header tank level.


Yes, and you would need to use a similar system in your setup.

However, in certain circumstances (such as mine), you can take advantage of
the fact that the water goes nowhere to remove the expense, space and
inconvenience of having the header tank. In your case, I don't think you can
and you need a conventional vented tank arrangement.


Brilliant - that means I understand it now. Thanks again.

Is this an area which thermal stores vary a lot in, and does "sealed
pressurised system" mean "fed from a header tank in the loft"?


No, it means a sealed circuit with no vent, filled from a hose from the
mains, with a pressure gauge, pressure relief valve and expansion pressure
vessel. There is no need for there to be a boiler in circuit to have one.
You can run a sealed pressurised circuit from the heat bank, with an
additional heat exchanger, but it adds to complexity.


I'm all for simplicity

Timbo
  #18   Report Post  
IMM
 
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"Tim" wrote in message
news
A thermal store has an inegral DHW coil.
A heat bank a DHW plate heat exchanger fed by a pump.

Q: But - which one? I've been all over the web and found:

McDonald Engineers' ThermFlow - simple
cylinder, use 2 external pumps (boiler
primary and CH)

Gledhill BoilerMate2000/SysteMate2000
(can't work out what the difference
is yet - possible one is direct and the other indirect??)
Very poncy
design with microprocessor control,
3 pumps (why there's a pump on the
mains water circuit I don't know) and lots
of sensors to go wrong. Looks
pretty though. Expensive at 1200 squids up,
but does include the controler
and all the pumps in a nice neat housing.


The Boilermate is an "integrated" store, that is the CH and DHW are run off
the store.
The Sytemate has the CH run direst from the boioer with the store being DHW
only.

All the controls/pumps etc in inside the neat casing in both. The control
systems are superb in both. The are not direct. I have a Systemate. They
are best available and state-of-the-art. They are self adaptive in that
they learn the boilers behaviour. They modulate the DHW pump speed to suit
the outlet temperature. A pump is on the mains water circuit, well it is on
the primary circuit, to pump heat into the plate heat exchanger. They are
also very reliable too.

Also look at http://www.rangecylinders.co.uk/prod...max/index.html
The Flowmax, which is a a well priced heat bank.

Best have a direct "integrated" heat bank.

Heatweb - Also looks complicated like the Gledhill, but not as neat.

Albion - simple again, like the McDonalds'.


But expensive.

Q: Would I want direct or indirect? Direct seems simpler - pump the boiler
primary through the bulk of the tank and the rads.


Yep.



  #19   Report Post  
IMM
 
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"Christian McArdle" wrote in message
et...
Shouldn't be a problem. Only got rads on 2 floors, with the cylider on

the
lower floor - I assume that will be OK?


Yes, but you must specify a model that can be topped up from a roof tank

and
be vented in the conventional way. The specific DPS Pandora I have

wouldn't
work, as it requires to be the highest point in the system. This wasn't a
problem for me, as I'm not running radiators through it, so it is the only
point in the system...


The Pandora is a DHW only heat bank.


  #20   Report Post  
IMM
 
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"Christian McArdle" wrote in message
. net...
Was there any particular reason you fed the rads directly from the

primary?

Yes, the radiators are (or will be when I convert the loft) the highest
point in the system. This means that they require a sealed pressurised
system. It is actually possible to have a sealed pressurised system fed

from
the heat bank, but this requires 2 additional pumps and an additional

plate
heat exchanger. The boiler and cylinder are already in the loft and I

didn't
want additional tanks above, even if they could have been accommodated
somehow.


Pressurised thermal stores, where the cylinder is pressurised like an
unvented cylinder, are available.




  #21   Report Post  
IMM
 
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"Grunff" wrote in message
...
Tim wrote:

Sounds good. Which type is it - also Pandora? I hadn't yet come across

the
idea of using an external heat plate exchanger until now...


I don't actually know - it came from Range, as did the flow switch which
drives it.


I was sort of convinced before (but worried that it might be a "fad"
product), but now that people say thay actually work I'm strongly
convinced that this is the way to go.

Half expecting someone to suggest I fit a combi instead! ;-/


Two combis - you always need two.


That is probably a more cost effective route.


  #22   Report Post  
IMM
 
Posts: n/a
Default


"Christian McArdle" wrote in message
. net...
Did you use any particularly special controller? I presume one could use

a
basic timeswitch/room thermostat combo (or zoned set thereof) doing the

CH
rad pump (and zone valves), with a thermostat on the thermal store doing
the boiler control? And couple the primary circuit pump to the boiler
control**


No, my system is bog standard S-Plan-Plus off the boiler. Standard 2

channel
programmer, with both CH and HW to always on. 4 zones, 3 heating (to be
expanded to 5) and 1 for the heat bank. All heating zones have

programmable
thermostats.

Had I run the radiators through the heatbank, I would have used a slightly
unusual control system, due to the radiator positioning requirements I

have.
Basically, I would have a second plate exchanger pumped loop.


DPS do other heat banks that are either direct or indirect eliminating the
need for extra plate heat exchangers, etc.


  #23   Report Post  
IMM
 
Posts: n/a
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"Christian McArdle" wrote in message
. net...
Half expecting someone to suggest I fit a combi instead! ;-/


Two combis - you always need two.


Or 2 multipoint heaters instead.


Another alternative. Have them with no electrics and hot water as long as
you have gas and water. Well done good thinking.


  #24   Report Post  
IMM
 
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"Christian McArdle" wrote in message
. net...
Is there a good way I can work this into the design at this stage

without
going to the lengths of using some sort of mixer system?


Nah. Put it a mixer system.


But take it off the thermal store/heat bank. Have only the boiler heat the
heat bank.


  #25   Report Post  
Andy Hall
 
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On Tue, 2 Nov 2004 18:33:41 -0000, "IMM" wrote:


"Christian McArdle" wrote in message
.net...
Was there any particular reason you fed the rads directly from the

primary?

Yes, the radiators are (or will be when I convert the loft) the highest
point in the system. This means that they require a sealed pressurised
system. It is actually possible to have a sealed pressurised system fed

from
the heat bank, but this requires 2 additional pumps and an additional

plate
heat exchanger. The boiler and cylinder are already in the loft and I

didn't
want additional tanks above, even if they could have been accommodated
somehow.


Pressurised thermal stores, where the cylinder is pressurised like an
unvented cylinder, are available.

But must be installed by an approved professional.



--

..andy

To email, substitute .nospam with .gl


  #26   Report Post  
IMM
 
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"Andy Hall" wrote in message
...
On Tue, 2 Nov 2004 18:33:41 -0000, "IMM" wrote:


"Christian McArdle" wrote in message
.net...
Was there any particular reason you fed the rads directly from the
primary?

Yes, the radiators are (or will be when I convert the loft) the highest
point in the system. This means that they require a sealed pressurised
system. It is actually possible to have a sealed pressurised system fed

from
the heat bank, but this requires 2 additional pumps and an additional

plate
heat exchanger. The boiler and cylinder are already in the loft and I

didn't
want additional tanks above, even if they could have been accommodated
somehow.


Pressurised thermal stores, where the cylinder is pressurised like an
unvented cylinder, are available.

But must be installed by an approved professional.


yep.


  #27   Report Post  
Tim S
 
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On Tue, 02 Nov 2004 18:26:56 +0000, IMM wrote:

The Boilermate is an "integrated" store, that is the CH and DHW are run
off the store.
The Sytemate has the CH run direst from the boioer with the store being
DHW only.


Thanks IMM - I see now.


All the controls/pumps etc in inside the neat casing in both. The control
systems are superb in both. The are not direct. I have a Systemate.
They are best available and state-of-the-art. They are self adaptive in
that they learn the boilers behaviour. They modulate the DHW pump speed
to suit the outlet temperature. A pump is on the mains water circuit,
well it is on the primary circuit, to pump heat into the plate heat
exchanger. They are also very reliable too.


They look like they are the best designed. I like the way that most of the
main pipes and pumps are presented at the front in an orderly way. Bit
worried about the clever microcontroller. But I suppose, in an emergency,
if it went pop, a little judicious bypassing with some wire would be
possible...

But, they do seem to have thought of everything - like pump overrun and
things. I had the fitter's guide off their website and it was
comprehensive to say the least.

Also look at http://www.rangecylinders.co.uk/prod...max/index.html
The Flowmax, which is a a well priced heat bank.


Ah - that must be what Grunff has - bit difficult searching for "range
cylinders" on google :/

Best have a direct "integrated" heat bank.

Heatweb - Also looks complicated like the Gledhill, but not as neat.

Albion - simple again, like the McDonalds'.


But expensive.


So far, I've seen two price lists. The Gledhill is pretty pricey, but
still worth it, for all the benefits I get (not least having a useable
5x6 ft bit of space back). However, I've seen one of the others (McDonald?
at around the £500-700 bracket depending on size. But after I'm finished
buying pumps, controllers, random bits and bobs I'm tempted by the more
expensive but nicely integrated solution.

Thanks indeed

Timbo
  #28   Report Post  
Tim S
 
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On Tue, 02 Nov 2004 19:25:51 +0000, IMM wrote:


"Andy Hall" wrote in message
...
But must be installed by an approved professional.


yep.


I've never been a fan of unvented systems (not that I've ever had one). I
just like the intrinsic safety inherent in a vented system. And
remembering to do the annual safety check... No, not for me...

Timbo
  #29   Report Post  
IMM
 
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"Tim S" wrote in message
news
On Tue, 02 Nov 2004 18:26:56 +0000, IMM wrote:

The Boilermate is an "integrated" store, that is the CH and DHW are run
off the store.
The Sytemate has the CH run direst from the boioer with the store being
DHW only.


Thanks IMM - I see now.


All the controls/pumps etc in inside the neat casing in both. The

control
systems are superb in both. The are not direct. I have a Systemate.
They are best available and state-of-the-art. They are self adaptive in
that they learn the boilers behaviour. They modulate the DHW pump speed
to suit the outlet temperature. A pump is on the mains water circuit,
well it is on the primary circuit, to pump heat into the plate heat
exchanger. They are also very reliable too.


They look like they are the best designed. I like the way that most of the
main pipes and pumps are presented at the front in an orderly way. Bit
worried about the clever microcontroller. But I suppose, in an emergency,
if it went pop, a little judicious bypassing with some wire would be
possible...

But, they do seem to have thought of everything - like pump overrun and
things. I had the fitter's guide off their website and it was
comprehensive to say the least.


Gledhill invented the modern version of the thermal store with a British Gas
collaboration in the 1980s. They are ahead of everyone else in most
respects.


Also look at http://www.rangecylinders.co.uk/prod...max/index.html
The Flowmax, which is a a well priced heat bank.


Ah - that must be what Grunff has - bit difficult searching for "range
cylinders" on google :/

Best have a direct "integrated" heat bank.

Heatweb - Also looks complicated like the Gledhill, but not as neat.

Albion - simple again, like the McDonalds'.


But expensive.


So far, I've seen two price lists. The Gledhill is pretty pricey, but
still worth it, for all the benefits I get (not least having a useable
5x6 ft bit of space back). However, I've seen one of the others (McDonald?
at around the £500-700 bracket depending on size. But after I'm finished
buying pumps, controllers, random bits and bobs I'm tempted by the more
expensive but nicely integrated solution.


Gledhill are the only company that will have a nice square box with very
heavy insulation and all the controls inside the box. Their Accolade
unvented cylinder is presented the same way. All the other makes look like
school boiler rooms. The Potterton Powermax is all in one box, boiler and
cylinder.

With a Gledhill everything is inside the box and this meas only a simple
boiler may be used outside, such as a Worcester Bosch Greenstar heating
boiler. Very simple and basic condensing boiler. A great advantage of heat
banks/thermal stores.




  #30   Report Post  
IMM
 
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"Tim S" wrote in message
news
On Tue, 02 Nov 2004 19:25:51 +0000, IMM wrote:


"Andy Hall" wrote in message
...
But must be installed by an approved professional.


yep.


I've never been a fan of unvented systems (not that I've ever had one). I
just like the intrinsic safety inherent in a vented system. And
remembering to do the annual safety check... No, not for me...


The mains pressure is reduced. A heat bank using a plate heat exchanger may
be very much higher.





  #31   Report Post  
IMM
 
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"Tim S" wrote in message
news
On Tue, 02 Nov 2004 18:26:56 +0000, IMM wrote:


They look like they are the best designed. I like the way that most of the
main pipes and pumps are presented at the front in an orderly way. Bit
worried about the clever microcontroller. But I suppose, in an emergency,
if it went pop, a little judicious bypassing with some wire would be
possible...


They can be easily converted to a conventional heat bank by installing a
blending valve on the DHW oulet and a flow switch on the cold mains in. A
stem thermostat can be installed in the sensors cylinder pocket.

But, they do seem to have thought of everything - like pump overrun and
things. I had the fitter's guide off their website and it was
comprehensive to say the least.


The modulated DHW pump prevents excessive mixing inside the store. Also
they are twin internal cylinders. They are basically an Accolade unvented
cylinder reversed. The Systemate is virtually identical

Also look at http://www.rangecylinders.co.uk/prod...max/index.html
The Flowmax, which is a a well priced heat bank.


Ah - that must be what Grunff has - bit difficult searching for "range
cylinders" on google :/

Best have a direct "integrated" heat bank.

Heatweb - Also looks complicated like the Gledhill, but not as neat.

Albion - simple again, like the McDonalds'.


But expensive.


So far, I've seen two price lists. The Gledhill is pretty pricey, but
still worth it, for all the benefits I get (not least having a useable
5x6 ft bit of space back). However, I've seen one of the others (McDonald?
at around the £500-700 bracket depending on size. But after I'm finished
buying pumps, controllers, random bits and bobs I'm tempted by the more
expensive but nicely integrated solution.


The Gledhill has the instant Switch electric backup system. This is
optional. It may be cheaper to have a second cheap gas boiler to do the
same job. You have to price it up. With a second gas boiler you heat the
whole house as well as the DHW.



  #32   Report Post  
timegoesby
 
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"Christian McArdle" wrote in message et...
Q: Would I want direct or indirect? Direct seems simpler - pump the boiler
primary through the bulk of the tank and the rads.


It has significant advantages and disadvantages. The main advantage is that
it allows the boiler to reheat the store in a very efficient manner, dumping
its full load into the cylinder, rather than relying on an indirect coil
that might not be able to transfer as much heat. This is particularly useful
if you are running radiators off the store. It also allows the boiler to use
a lower flow temperature (good for condensing) as there is no need to
provide a temperature differential that a heat exchanger would require. You
can run the boiler at 75C, rather than 82-85C.

The main disadvantage is that it doesn't allow sealed pressurised operation
of the boiler, a system which has a number of advantages, such as leak
detection and protection, pump over prevention, easier filling & flushing,
allowing radiators high up, etc.

So - from people that fitted thermal store cylinders: are they any good
and which one did you use? Any general theories/opinions also most welcome
:-)


I have a DPS Pandora heat bank (you refer to these as the "heatweb"). It is
an indirect type, as there are likely to be radiators as the highest point
in the system, so I wanted sealed pressurised operation. The rads are off
the boiler primary, not from the heat bank.

It is absolutely excellent and works entirely as described. It has been
fitted for over a year and I still haven't had to top it up (manual fill
version). I believe the Gledhill may be technically superior to the model I
have. In particular, it is my understanding that the Gledhill varies pump
speed to maintain heat bank stratification. However, I haven't in practice
found destratification to be a problem as the system never really runs out
of hot water.

The biggest test was filling a 750 litre birthing pool to 40C. It managed
this in just over 40 minutes, although the outlet temperature did drop to
about the required 40C by the time it had completed.

In conclusion, I would definitely fit this type of system again. Although my
parent's Megaflo also provides excellent performance, I prefer the easy
maintenance of the heat bank.

BTW, I'd avoid the traditional thermal store type devices. I would only
choose a model with a plate heat exchanger for DHW operation.

Christian.


On searching the web on thermal stores, I came across this.
"For new house builders to get planning permission for your home from
the local authority, your hot water has to be drinkable (Potable). Hot
water can no longer be tank feed from lofts for new homes as it's
inefficient and not healthy."

This was taken fropm this site.
http://www.ho****erlimited.co.uk/thermal_stores.htm

Is this true? If this is true cold water tank systems are outlawed on
new houses and extensions.
  #33   Report Post  
Tim
 
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On Wed, 03 Nov 2004 04:33:13 -0800, timegoesby wrote:


On searching the web on thermal stores, I came across this.
"For new house builders to get planning permission for your home from
the local authority, your hot water has to be drinkable (Potable). Hot
water can no longer be tank feed from lofts for new homes as it's
inefficient and not healthy."

This was taken fropm this site.
http://www.ho****erlimited.co.uk/thermal_stores.htm

Is this true? If this is true cold water tank systems are outlawed on
new houses and extensions.


Yeah - I came across that...

I've never heard of this before and would be inclined to think that
they're talking b*ll*cks to get you to buy their systems.

Always be wary of quotes about the law etc. made by a vendor...

Timbo
  #34   Report Post  
W
 
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On Tue, 2 Nov 2004 15:10:08 -0000, "Christian McArdle"
wrote:

BTW, I'd avoid the traditional thermal store type devices. I would only
choose a model with a plate heat exchanger for DHW operation.


Why? I was thinking of getting one of these (Albion mainsflow)
because of their simplicity.

W

  #35   Report Post  
W
 
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On Tue, 2 Nov 2004 18:26:56 -0000, "IMM" wrote:

Albion - simple again, like the McDonalds'.


But expensive.


??? According to the price lists that I have seen Albion is the
cheapest.

W




  #36   Report Post  
IMM
 
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"W" wrote in message
...
On Tue, 2 Nov 2004 18:26:56 -0000, "IMM" wrote:

Albion - simple again, like the McDonalds'.


But expensive.


??? According to the price lists that I have seen Albion is the
cheapest.


Prices must have changed.


  #37   Report Post  
Christian McArdle
 
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BTW, I'd avoid the traditional thermal store type devices. I would only
choose a model with a plate heat exchanger for DHW operation.


Why? I was thinking of getting one of these (Albion mainsflow)
because of their simplicity.


Advantages:
1. Simplicity.
2. No electrical power.

Disadvantages:
1. Reduced pressure (may not matter, depending on your supply).
2. Water temperature variable with flow (can be fixed with external TMV).
3. Lower maximum flow rate before temp drops too low.
4. Internal heat exchanger makes descaling difficult and replacement
impossible.
5. Worse destratification compared to external loop, leads to more gradual
temp drop over long draw off, rather than remaining hot until sharper cut
off.

Christian.


  #38   Report Post  
IMM
 
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"W" wrote in message
...
On Tue, 2 Nov 2004 18:26:56 -0000, "IMM" wrote:

Albion - simple again, like the McDonalds'.


But expensive.


??? According to the price lists that I have seen Albion is the
cheapest.


What price list?


  #39   Report Post  
IMM
 
Posts: n/a
Default


"W" wrote in message
...
On Tue, 2 Nov 2004 15:10:08 -0000, "Christian McArdle"
wrote:

BTW, I'd avoid the traditional thermal store type devices. I would only
choose a model with a plate heat exchanger for DHW operation.


Why? I was thinking of getting one of these (Albion mainsflow)
because of their simplicity.


Internal coils are not as efficient as a plate heat exchanger with plates
delivering higher flow rates. Coils are a pig to descale, while a plate can
be just screwed off and de-scaled as a DIY job. Replacing then plate is an
equally simple job. The only thing extra using a plate is a normal CH pump,
available locally everywhere, and a flow switch. Not much extra complexity.
You can also add extra plates for a higher flowrates, try doing that with an
internal coil.





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IMM
 
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"Tim" wrote in message
news
Hi

*** Preamble ************************************************** *****

The ongoing wibblings of moving my family in with Dad... [Dad's house is a
3 bedroom bungalow with roof converstion fitted with "evolved" CH, but new
boiler - vented type]


Also try:

http://www.elsonho****er.co.uk/

For square thermal stores.



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