Hello,

I am installing/getting installed a new boiler and new bathroom with
shower, and am after some advice to find my way through the miriad of
possibilities. I have found lots of good advice in the archive but
have some specific queries.

The existing system is a gravity system with a 25 year old boiler
situated in the bathroom. It works well enough (with occasional
hiccups) but I want to move it and it seems a good moment to replace
it.

The house is a large 3/4 bedroom Victorian terraced house with one
bathroom (shower in bath) and there are 3 residents - 2 adults, 1
child. I would like to build in capacity for an additional bathroom
with shower.

I am concerned about energy consumption and cutting my fuel bills so a
Condensing boiler seems the way to go.

The next question is Combination or Conventional boiler. I had a combi
in my last house and liked the convenience. Against that I am
concerned that the pressure I would get wouldn't be that great (a
local plumber says that mains pressure is variable in the area and has
dropped recently) and whether a combi would be up to the task. I have
a Gravity system at the moment that works so I suppose if it aint
broke don't fix it ? So Conventional boiler it is.

Reccomendations for Condensing Conventional Boilers? From searching
the archive, in my budget, the Vaillant Eco range and the Keston
Celsius 25 get good press. Any comments ? How do I work out what Kw
rating I need for my house ?

I like a decent shower. It is good at the moment a mixer tap with a
victorian rose head , giving low pressure but a flow rate of approx 20
l/min. This is achieved by a 22mm feed from hot water tank on floor
above. The cold water tank is in the attic, two floors, approx 3m
above the shower head.

I have been looking at thermostatic mixers and they seem to need more
water pressure than that. What I don't want is to change everything
and find that I have a much worse shower.

So I believe the options are low pressure thermostatic mixer, venturi
shower, installing a pump or indeed a Unvented system. One by one:

Low pressure thermostatic mixer - Do they exist ? Would they just give
a dribble ?

Venturi shower - Seem to be mixed feelings on these

Pump - Do I site this next to the hot water tank or by the shower ?
Single ? Twin ? Negative ? Positive ? What does this all mean ? Is an
integrated power shower a better idea? Could it pump water for
possible second bathroom too.

Unvented system - What pressure would this actually give ? Same as
mains in which case similar problems to Combi ? Pipe from street is
15mm, upgrading is possible, is it effective ? very expensive ?

Also any reccomendations on shower fittings ? Looking at Hansgrohe,
Mira, Grohe, Aqualisa.

Apologies for length of query, just trying to give all the info. All
help much appreciated.

Bjorn Ventris
(Remove the NOSPAM).

"Bjorn" wrote in message
om...
Hello,

I am installing/getting installed a new boiler and new bathroom with
shower, and am after some advice to find my way through the miriad of
possibilities. I have found lots of good advice in the archive but
have some specific queries.

The existing system is a gravity system with a 25 year old boiler
situated in the bathroom. It works well enough (with occasional
hiccups) but I want to move it and it seems a good moment to replace
it.

The house is a large 3/4 bedroom Victorian terraced house with one
bathroom (shower in bath) and there are 3 residents - 2 adults, 1
child. I would like to build in capacity for an additional bathroom
with shower.

I am concerned about energy consumption and cutting my fuel bills so a
Condensing boiler seems the way to go.

The next question is Combination or Conventional boiler. I had a combi
in my last house and liked the convenience. Against that I am
concerned that the pressure I would get wouldn't be that great (a
local plumber says that mains pressure is variable in the area and has
dropped recently) and whether a combi would be up to the task. I have
a Gravity system at the moment that works so I suppose if it aint
broke don't fix it ? So Conventional boiler it is.

Reccomendations for Condensing Conventional Boilers? From searching
the archive, in my budget, the Vaillant Eco range and the Keston
Celsius 25 get good press. Any comments ? How do I work out what Kw
rating I need for my house ?

I like a decent shower. It is good at the moment a mixer tap with a
victorian rose head , giving low pressure but a flow rate of approx 20
l/min. This is achieved by a 22mm feed from hot water tank on floor
above. The cold water tank is in the attic, two floors, approx 3m
above the shower head.

I have been looking at thermostatic mixers and they seem to need more
water pressure than that. What I don't want is to change everything
and find that I have a much worse shower.

So I believe the options are low pressure thermostatic mixer, venturi
shower, installing a pump or indeed a Unvented system. One by one:

Low pressure thermostatic mixer - Do they exist ? Would they just give
a dribble ?

They exist. Not a dribble, but not startling either.

Venturi shower - Seem to be mixed feelings on these

Get a good and make sure it works on the correct mains pressure.

Pump - Do I site this next to the hot
water tank or by the shower ?

Wherever convenient.

Single ? Twin ? Negative ? Positive ? What does this all mean ? Is an
integrated power shower a better idea? Could it pump water for
possible second bathroom too.

A twin. One hot one cold. The hot from the top of the cylinder using a
Surrey flange and cold off the tank in the loft.

Unvented system - What pressure would this actually give ? Same as
mains in which case similar problems to Combi ? Pipe from street is
15mm, upgrading is possible, is it effective ? very expensive ?

Unvented cylinders are pressure reduced to approx 3.5 bar for steel and 2
bar copper. A combi is not reduced. A heat bank is a far better solution
than an unvented cylinder.

Also any reccomendations on shower fittings ?
Looking at Hansgrohe,
Mira, Grohe, Aqualisa.

Any good one.

You say you are keeping the existing gravity fed system with a tank in the
loft. If the tank is fine then keep it. Replace the cylinder with a quick
recovery model. Try the Telford Typhoon 115 litre model as it will do two
bathrooms when the boiler is set to max and using a priority system. The
problem now is the high pressure shower. So get a condensing combi and use
the water section for showers only. The Ideal Icos is good, and sabout the
same price as the eqiv system boiler.
http://www.discountedheating.co.uk/shop/acatalog/
This eliminates a power shower pump. A good pump is £200-250, so the combi
ways is the best and no vibrations and noise. Have the CH side of the
boiler act as a normal CH/DHW (cylinder) system.

If the tank has to go then consider a combi cylinder with a quick recovery
coil of 115 litres hot and 115 litres cold. See Telford, who will make one
to suit as will Range.
http://www.telford-group.com/trident.htm
http://www.range-cylinders.co.uk

Many other cylinder makers may help you.

A combi cylinder can go in the airing cupboard and eliminate the cold tank
in the loft, or go in the loft and liberate an airing cupboard.



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"IMM" wrote in message ...

Unvented cylinders are pressure reduced to approx 3.5 bar for steel and 2
bar copper. A combi is not reduced. A heat bank is a far better solution
than an unvented cylinder.

Thanks for the advice, but what's a heat bank ? Quick recovery hot
water tank sounds like the way to go. You reccomend Telford ?

Richard wrote in message . ..
(Bjorn) wrote:

Hello,

snip
Reccomendations for Condensing Conventional Boilers? From searching
the archive, in my budget, the Vaillant Eco range and the Keston
Celsius 25 get good press. Any comments ? How do I work out what Kw
rating I need for my house ?

I have a keston celcius, it works fine. cheap to run and fast at
heating my quick recovery hot water tank. A definate must to get a
new tank with the new boiler. Never run out of hot water yet even with
a full house with 4 adults all having long showers after each other.

How big is your hot water tank ? Who makes it ? How much ?

Bjorn

"Bjorn" wrote in message
om...
"IMM" wrote in message
...

Unvented cylinders are pressure reduced to approx 3.5 bar for steel and
2
bar copper. A combi is not reduced. A heat bank is a far better
solution
than an unvented cylinder.

Thanks for the advice, but what's a heat bank ?

See:
http://www.heatweb.com
They will explain.

Quick recovery hot
water tank sounds like the way
to go. You reccomend Telford ?

Good and cheap, from Travis Perkins. See Albion which will guide you on
sizing.
http://www.albion-online.co.uk
Quick recovery cylinder using a priority system (3-way diverter valve) can
mean the cyoinder is downsized to 80 litres from say 114 litres.







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(Bjorn) wrote:

Richard wrote in message . ..
(Bjorn) wrote:

Hello,

snip
Reccomendations for Condensing Conventional Boilers? From searching
the archive, in my budget, the Vaillant Eco range and the Keston
Celsius 25 get good press. Any comments ? How do I work out what Kw
rating I need for my house ?

I have a keston celcius, it works fine. cheap to run and fast at
heating my quick recovery hot water tank. A definate must to get a
new tank with the new boiler. Never run out of hot water yet even with
a full house with 4 adults all having long showers after each other.

How big is your hot water tank ? Who makes it ? How much ?

Bjorn

As far as I can remember it was about £150. It is 200l (bigger than
usual as I have a very big bath which takes 250 liters to fill up.) I
con fess that it is just a new ordinary lagged copper cylinder, and
performs to part L and is a quickish recovery cylinder. Which is
better than the older cylinders but still not as good as some more
expensive suggestions that come up here. It works for me. I have never
run out of water and the shower eats it up at 20l a min output. You
could get a calculator out and work out the math and determine that a
very quick recovery cylinder would do for you and take up less room,
but they are more expensive. My cylinder is the same width as the old
one, just a few inches taller, so why waste the money IMHO unless
space is a premium.

Richard

"Richard" wrote in message
...
(Bjorn) wrote:

Richard wrote in message
. ..
(Bjorn) wrote:

Hello,

snip
Reccomendations for Condensing Conventional Boilers? From searching
the archive, in my budget, the Vaillant Eco range and the Keston
Celsius 25 get good press. Any comments ? How do I work out what Kw
rating I need for my house ?

I have a keston celcius, it works fine. cheap to run and fast at
heating my quick recovery hot water tank. A definate must to get a
new tank with the new boiler. Never run out of hot water yet even with
a full house with 4 adults all having long showers after each other.

How big is your hot water tank ? Who makes it ? How much ?

Bjorn

As far as I can remember it was about £150. It is 200l (bigger than
usual as I have a very big bath which takes 250 liters to fill up.) I
con fess that it is just a new ordinary lagged copper cylinder, and
performs to part L and is a quickish recovery cylinder. Which is
better than the older cylinders but still not as good as some more
expensive suggestions that come up here.

It is not quick recovery. It is a standard cylinder. Part L is the new
better standard. With a quick recovery you could have got away with a 150
litre cylinder and maybe a 125. Quick recovery are cheaper to run as the
boiler is operating more efficiently.

You could get a calculator out and
work out the math and determine that a
very quick recovery cylinder would do for
you and take up less room,
but they are more expensive.

The Telford Typhoons are not expensive at all.

My cylinder is the same width as the old
one, just a few inches taller, so why waste
the money IMHO unless
space is a premium.

You have to understand what a quick recovery gives you. I cannot see the
need to fit Part Ls.



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On Tue, 5 Aug 2003 22:10:48 +0100, "IMM" wrote:


"Andy Hall" wrote in message
.. .


Unvented cylinders are pressure
reduced to approx 3.5 bar for steel and
2 bar copper. A combi is not reduced.
A heat bank is a far better solution
than an unvented cylinder.

Thanks for the advice, but what's a heat bank ?

See:
http://www.heatweb.com
They will explain.

DPS make a lot of claims about the performance of their systems but
don't quote all the operating conditions. For any system which
instantly heats mains cold water, be it this or a combi, you need to
look very carefully at the small print. Combis are usually quoted
with a flow rate that they can produce based on a certain temperature
rise - normally 30 or 35 degrees. This means that if the water
temperature from the mains drops to 5-7 degrees as it can in winter,
the output temperature will only be at around 40 - i.e. about shower
temperature. So if you consider a 15 litre/minute combi, it may be
enough to run one decent shower (just), but it won't run two.

You can pre-heat mains water if running an UFH system. Run the mains pipe
through the concrete slab. This will pre-heat water to approx 25C, so a
combi in winter will deliver 60C at say 15 litres/min. In summer the cold
water mains pipe at approx 10C temp will cool the floor. Simple and easy to
do and gains all around.

This is a nice theory, but I am not convinced that it would be as good
as you describe. You are talking about a 20 degree rise at 15
litres per minute. That needs just over half the energy that a combi
would require at similar volume (about 21kW, as I calculate it).
Getting that through a heat exchanger made of MDPE pipe when the heat
source (i.e. the floor) is not that much warmer is not very plausible.
It would need a very long length of pipe and that would add problems
with flow resistance.



I have not seen similar figures quoted for heat banks. That is not
to say that the technology is bad, but remember that the amount of
heat that you store is directly proportional to the volume of the
cylinder and the temperature. In a heatbank you normally run it at
76-80 degrees as compared with a conventional HW cylinder which is
normally run at 60 degrees - so you store about 25% more energy in the
same space. However, when that energy is used up, the performance
degenerates to that of a combi of equivalent power.

So you never run out of hot water.

Provided that the cylinder is large enough, which takes us back to the
point that it is only as good as the energy stored plus the energy
that can be delivered into the heatbank from the boiler while the
former is delivering energy to the heat exchanger.



Therefore in considering this, do your
sums in terms of whether there
really is much of a space saving

There is.

It's easy enough to calculate that when comparing a heatbank at 76
degrees with a conventional cylinder at 60 degrees.

For the same amount of stored energy, the height of the cylinder could
be reduced by 60/76. For a 1500mm high cylinder that would be to
1185mm approx. - a saving of 315mm - about a foot. Enough space to
put a couple of pairs of shoes. Hmmmm. Not a decision making
criterion that seems that big an issue unless you are in a small flat.



- the claims made are optimistic
IMHO. Unless you are really tight
on space for a cylinder, you can
achieve an equivalent or better
result by using a pressurised cylinder
and storing the hot water to be used.

Behave yourself. A heat banks outperform an unvented cylinder an day.
Unvented cylinders required pressure to be reduced to, Unvented cylinders
are pressure reduced to approx 3.5 bar for steel and 2 bar copper. A combi
or heat bank need not be reduced.

A heat bank is a far better solution
than an unvented cylinder as it does not run at high pressures, have large
bore overflow pipes, tundishes, pressure control equipment, etc.


This isn't really relevant because the flow rate through a combi is
the key issue, not the pressure that it will withstand. Pressure
and flow control is required on most mains fed systems anyway,
regardless of technology, in order to balance the flows of hot and
cold to a reasonable extent.


I therefore installed a cylinder capable
of running pressurised but am
currently running it from a roof tank. It
is entirely satisfactory for two people
and two teenagers with two baths, two
showers or one of
each being run simultaneously.

And very large.

200 litres is not particularly large and could not be substantially
reduced by the use of heatbank technology as already illustrated.


The cylinder is a fast recovery type
of 200 litres with a boiler able to deliver 28kW.

Unvented cylinders are minimally quick recovery. They can't match an open
vented cylinder.

That depends on the cylinder design and specifically the heating coil.


You should have fitted a heat bank and then it would be easy to convert it
when a decent mains pipe comes along.


In fact I could since the cylinder has plenty of connection points.
I am also quite impressed with the Swedish made GEA Ecobraze heat
exchangers - the one I have for the workshop circuit performs very
well.

However, the match of a direct heatbank to a more sophisticated
condensing boiler is not a good one, and this does not leave any
significant advantages for the heat bank, unless one is really tight
on space.






..andy

To email, substitute .nospam with .gl

"Andy Hall" wrote in message
...
On Tue, 5 Aug 2003 22:10:48 +0100, "IMM" wrote:


"Andy Hall" wrote in message
.. .


Unvented cylinders are pressure
reduced to approx 3.5 bar for steel and
2 bar copper. A combi is not reduced.
A heat bank is a far better solution
than an unvented cylinder.

Thanks for the advice, but what's a heat bank ?

See:
http://www.heatweb.com
They will explain.

DPS make a lot of claims about the performance of their systems but
don't quote all the operating conditions. For any system which
instantly heats mains cold water, be it this or a combi, you need to
look very carefully at the small print. Combis are usually quoted
with a flow rate that they can produce based on a certain temperature
rise - normally 30 or 35 degrees. This means that if the water
temperature from the mains drops to 5-7 degrees as it can in winter,
the output temperature will only be at around 40 - i.e. about shower
temperature. So if you consider a 15 litre/minute combi, it may be
enough to run one decent shower (just), but it won't run two.

You can pre-heat mains water if running an UFH system. Run the mains
pipe
through the concrete slab. This will pre-heat water to approx 25C, so a
combi in winter will deliver 60C at say 15 litres/min. In summer the
cold
water mains pipe at approx 10C temp will cool the floor. Simple and easy
to
do and gains all around.

This is a nice theory, but I am not convinced that it would be as good
as you describe. You are talking about a 20 degree rise at 15
litres per minute. That needs just over half the energy that a combi
would require at similar volume (about 21kW, as I calculate it).
Getting that through a heat exchanger made of MDPE pipe when the heat
source (i.e. the floor) is not that much warmer is not very plausible.
It would need a very long length of pipe and that would add problems
with flow resistance.

MDPE? You can use two way santoprene pipe. This is 2 or 3 way counter feed
pipe. Mains water in one way hot water in the other. Running PEX side by
side is good enough. Many in the USA have done this and reported good
results.

The USA has different water regs to use. They use a hot water cylinder and
take off fresh water and run it through a non-ferrous UFH system. Many
companies run cold mains water through the same pipe loop by turning a
manual 3-way valve to cool the floor in summer.

I have not seen similar figures quoted for heat banks. That is not
to say that the technology is bad, but remember that the amount of
heat that you store is directly proportional to the volume of the
cylinder and the temperature. In a heatbank you normally run it at
76-80 degrees as compared with a conventional HW cylinder which is
normally run at 60 degrees - so you store about 25% more energy in the
same space. However, when that energy is used up, the performance
degenerates to that of a combi of equivalent power.

So you never run out of hot water.

Provided that the cylinder is large enough, which takes us back to the
point that it is only as good as the energy stored plus the energy
that can be delivered into the heatbank from the boiler while the
former is delivering energy to the heat exchanger.

No. The system acts like a combi as a fall back.

Therefore in considering this, do your
sums in terms of whether there
really is much of a space saving

There is.

It's easy enough to calculate that when comparing a heatbank at 76
degrees with a conventional cylinder at 60 degrees.

For the same amount of stored energy, the height of the cylinder could
be reduced by 60/76. For a 1500mm high cylinder that would be to
1185mm approx. - a saving of 315mm - about a foot. Enough space to
put a couple of pairs of shoes. Hmmmm. Not a decision making
criterion that seems that big an issue unless you are in a small flat.

And millions are.

- the claims made are optimistic
IMHO. Unless you are really tight
on space for a cylinder, you can
achieve an equivalent or better
result by using a pressurised cylinder
and storing the hot water to be used.

Behave yourself. A heat banks outperform an unvented cylinder an day.
Unvented cylinders required pressure to be reduced to, Unvented cylinders
are pressure reduced to approx 3.5 bar for steel and 2 bar copper. A
combi
or heat bank need not be reduced.

A heat bank is a far better solution
than an unvented cylinder as it does not run at high pressures, have
large
bore overflow pipes, tundishes, pressure control equipment, etc.


This isn't really relevant because the flow rate through a combi is
the key issue, not the pressure that it will withstand. Pressure
and flow control is required on most mains fed systems anyway,
regardless of technology, in order to balance the flows of hot and
cold to a reasonable extent.

Combi??

I therefore installed a cylinder capable
of running pressurised but am
currently running it from a roof tank. It
is entirely satisfactory for two people
and two teenagers with two baths, two
showers or one of
each being run simultaneously.

And very large.

200 litres is not particularly large and could not be substantially
reduced by the use of heatbank technology as already illustrated.

It could. Store water at 80C and have a large output boiler to assist when
drawing hot water.

The cylinder is a fast recovery type
of 200 litres with a boiler able to deliver 28kW.

Unvented cylinders are minimally quick recovery. They can't match an open
vented cylinder.

That depends on the cylinder design and
specifically the heating coil.

Yes, and unvented cylinders do not have very large coils.

You should have fitted a heat bank and then it would be easy to convert
it
when a decent mains pipe comes along.

In fact I could since the cylinder has plenty of connection points.
I am also quite impressed with the Swedish made GEA Ecobraze heat
exchangers - the one I have for the workshop circuit performs very
well.

Those sold by DPS are about the best. I forget right now who makes them,
but they are about the most efficient and not expensive.

However, the match of a direct heatbank to a more sophisticated
condensing boiler is not a good one, and this does not leave any
significant advantages for the heat bank, unless one is really tight
on space.

A smart condenser will work well with a heat bank. A heat bank with the top
half at 76-80C for DHW and the bottom at 45C for UFH works very well with
condensers. A diverter valve sends the boilers output to either section.



---
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On Wed, 6 Aug 2003 00:54:56 +0100, "IMM" wrote:



This is a nice theory, but I am not convinced that it would be as good
as you describe. You are talking about a 20 degree rise at 15
litres per minute. That needs just over half the energy that a combi
would require at similar volume (about 21kW, as I calculate it).
Getting that through a heat exchanger made of MDPE pipe when the heat
source (i.e. the floor) is not that much warmer is not very plausible.
It would need a very long length of pipe and that would add problems
with flow resistance.

MDPE? You can use two way santoprene pipe. This is 2 or 3 way counter feed
pipe. Mains water in one way hot water in the other. Running PEX side by
side is good enough. Many in the USA have done this and reported good
results.

The USA has different water regs to use. They use a hot water cylinder and
take off fresh water and run it through a non-ferrous UFH system. Many
companies run cold mains water through the same pipe loop by turning a
manual 3-way valve to cool the floor in summer.

Fine, but probably not applicable here. SInce most houses in the
U.S. have timber floors, I wonder where this is used.




Provided that the cylinder is large enough, which takes us back to the
point that it is only as good as the energy stored plus the energy
that can be delivered into the heatbank from the boiler while the
former is delivering energy to the heat exchanger.

No. The system acts like a combi as a fall back.

Sure, but the performance level will have dropped off.


For the same amount of stored energy, the height of the cylinder could
be reduced by 60/76. For a 1500mm high cylinder that would be to
1185mm approx. - a saving of 315mm - about a foot. Enough space to
put a couple of pairs of shoes. Hmmmm. Not a decision making
criterion that seems that big an issue unless you are in a small flat.

And millions are.

... and millions are not. Either way, I don't see this as a major
selling point. Minor one maybe.



This isn't really relevant because the flow rate through a combi is
the key issue, not the pressure that it will withstand. Pressure
and flow control is required on most mains fed systems anyway,
regardless of technology, in order to balance the flows of hot and
cold to a reasonable extent.

Combi??

To balance at the points of delivery.




200 litres is not particularly large and could not be substantially
reduced by the use of heatbank technology as already illustrated.

It could. Store water at 80C and have a large output boiler to assist when
drawing hot water.

The net equation is still the same. It doesn't matter whether the
boiler is providing the energy via a conventional cylinder or a
heatbank. Once the stored energy is used up, both arrangements fall
back to combi behaviour. The only real difference is that in the
heatbank case you have stored 25% more energy in a given volume or a
small reduction in space.

Sorry, but I don't think it's that big a deal.



The cylinder is a fast recovery type
of 200 litres with a boiler able to deliver 28kW.

Unvented cylinders are minimally quick recovery. They can't match an open
vented cylinder.

That depends on the cylinder design and
specifically the heating coil.

Yes, and unvented cylinders do not have very large coils.

That depends on what you order and from whom.



You should have fitted a heat bank and then it would be easy to convert
it
when a decent mains pipe comes along.

In fact I could since the cylinder has plenty of connection points.
I am also quite impressed with the Swedish made GEA Ecobraze heat
exchangers - the one I have for the workshop circuit performs very
well.

Those sold by DPS are about the best. I forget right now who makes them,
but they are about the most efficient and not expensive.

Looking at the pictures, it looks as though these are the ones that
they carry.


However, the match of a direct heatbank to a more sophisticated
condensing boiler is not a good one, and this does not leave any
significant advantages for the heat bank, unless one is really tight
on space.

A smart condenser will work well with a heat bank. A heat bank with the top
half at 76-80C for DHW and the bottom at 45C for UFH works very well with
condensers. A diverter valve sends the boilers output to either section.


We've already had this discussion and I illustrated why this would not
be the case. I'm not going to go over the same ground again.







---

..andy

To email, substitute .nospam with .gl

"Andy Hall" wrote in message
...
On Wed, 6 Aug 2003 00:54:56 +0100, "IMM" wrote:



This is a nice theory, but I am not convinced that it would be as good
as you describe. You are talking about a 20 degree rise at 15
litres per minute. That needs just over half the energy that a combi
would require at similar volume (about 21kW, as I calculate it).
Getting that through a heat exchanger made of MDPE pipe when the heat
source (i.e. the floor) is not that much warmer is not very plausible.
It would need a very long length of pipe and that would add problems
with flow resistance.

MDPE? You can use two way santoprene pipe. This is 2 or 3 way counter
feed
pipe. Mains water in one way hot water in the other. Running PEX side
by
side is good enough. Many in the USA have done this and reported good
results.

The USA has different water regs to use. They use a hot water cylinder
and
take off fresh water and run it through a non-ferrous UFH system. Many
companies run cold mains water through the same pipe loop by turning a
manual 3-way valve to cool the floor in summer.

Fine, but probably not applicable here. SInce most houses in the
U.S. have timber floors, I wonder where this is used.

It was used in a concrete floor.

Provided that the cylinder is large enough, which takes us back to the
point that it is only as good as the energy stored plus the energy
that can be delivered into the heatbank from the boiler while the
former is delivering energy to the heat exchanger.

No. The system acts like a combi as a fall back.

Sure, but the performance level will have dropped off.

The point is you "never" run out of hot water. Your hot water is 2 stage of
high flow and then low flow.

For the same amount of stored energy, the height of the cylinder could
be reduced by 60/76. For a 1500mm high cylinder that would be to
1185mm approx. - a saving of 315mm - about a foot. Enough space to
put a couple of pairs of shoes. Hmmmm. Not a decision making
criterion that seems that big an issue unless you are in a small flat.

And millions are.

.. and millions are not. Either way, I don't see this as a major
selling point. Minor one maybe.

Few British house have space to spare, hence combi boilers account for
60-70% of the one million boilers sold each year.

This isn't really relevant because the flow rate through a combi is
the key issue, not the pressure that it will withstand. Pressure
and flow control is required on most mains fed systems anyway,
regardless of technology, in order to balance the flows of hot and
cold to a reasonable extent.

Combi??

To balance at the points of delivery.

It was about unvented cylinders, heat banks.

200 litres is not particularly large and could not be substantially
reduced by the use of heatbank technology as already illustrated.

It could. Store water at 80C and have a large output boiler to assist
when
drawing hot water.

The net equation is still the same. It doesn't matter whether the
boiler is providing the energy via a conventional cylinder or a
heatbank. Once the stored energy is used up, both arrangements fall
back to combi behaviour.

No. With a beat bank the boioers output goes straiught to the DHW draw off.
This si noit the case with a vented or unvented cylinder.

The only real difference is that in the
heatbank case you have stored 25%
more energy in a given volume or a
small reduction in space.

You don't understand.

The cylinder is a fast recovery type
of 200 litres with a boiler able to deliver 28kW.

Unvented cylinders are minimally quick recovery. They can't match an
open
vented cylinder.

That depends on the cylinder design and
specifically the heating coil.

Yes, and unvented cylinders do not have very large coils.

That depends on what you order and from whom.

Again.. unvented cylinders do not have very large coils.

You should have fitted a heat bank and then it would be easy to
convert
it
when a decent mains pipe comes along.

In fact I could since the cylinder has plenty of connection points.
I am also quite impressed with the Swedish made GEA Ecobraze heat
exchangers - the one I have for the workshop circuit performs very
well.

Those sold by DPS are about the best. I forget right now who makes them,
but they are about the most efficient and not expensive.

Looking at the pictures, it looks as though these are the ones that
they carry.

However, the match of a direct heatbank to a more sophisticated
condensing boiler is not a good one, and this does not leave any
significant advantages for the heat bank, unless one is really tight
on space.

A smart condenser will work well with a heat bank. A heat bank with the
top
half at 76-80C for DHW and the bottom at 45C for UFH works very well with
condensers. A diverter valve sends the boilers output to either section.

We've already had this discussion and I illustrated why this would not
be the case. I'm not going to go over the same ground again.

You don't understand.


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On Wed, 6 Aug 2003 11:09:33 +0100, "IMM" wrote:



The USA has different water regs to use. They use a hot water cylinder
and
take off fresh water and run it through a non-ferrous UFH system. Many
companies run cold mains water through the same pipe loop by turning a
manual 3-way valve to cool the floor in summer.

Fine, but probably not applicable here. SInce most houses in the
U.S. have timber floors, I wonder where this is used.

It was used in a concrete floor.

Hmmm.


Provided that the cylinder is large enough, which takes us back to the
point that it is only as good as the energy stored plus the energy
that can be delivered into the heatbank from the boiler while the
former is delivering energy to the heat exchanger.

No. The system acts like a combi as a fall back.

Sure, but the performance level will have dropped off.

The point is you "never" run out of hot water. Your hot water is 2 stage of
high flow and then low flow.

That's fine if you find that type of performance acceptable. My
point was to highlight that this low flow situation would happen.

I would prefer to see the cylinder adequately sized regardless of
whether it is used in a conventional way or as a heatbank.



For the same amount of stored energy, the height of the cylinder could
be reduced by 60/76. For a 1500mm high cylinder that would be to
1185mm approx. - a saving of 315mm - about a foot. Enough space to
put a couple of pairs of shoes. Hmmmm. Not a decision making
criterion that seems that big an issue unless you are in a small flat.

And millions are.

.. and millions are not. Either way, I don't see this as a major
selling point. Minor one maybe.

Few British house have space to spare, hence combi boilers account for
60-70% of the one million boilers sold each year.

I don't think that you can deduce that as a causal connection, merely
as a contributing factor. Others are that to an extent, a combi
installation may take some time cost out of installation in new
builds. In terms of replacements, if the water supply and appliance
size are inadequate, we have an unhappy customer since they have
bought a 21st century version of the geyser.




This isn't really relevant because the flow rate through a combi is
the key issue, not the pressure that it will withstand. Pressure
and flow control is required on most mains fed systems anyway,
regardless of technology, in order to balance the flows of hot and
cold to a reasonable extent.

Combi??

To balance at the points of delivery.

It was about unvented cylinders, heat banks.

I said any system using mains fed hot water as opposed to a roof tank.


200 litres is not particularly large and could not be substantially
reduced by the use of heatbank technology as already illustrated.

It could. Store water at 80C and have a large output boiler to assist
when
drawing hot water.

The net equation is still the same. It doesn't matter whether the
boiler is providing the energy via a conventional cylinder or a
heatbank. Once the stored energy is used up, both arrangements fall
back to combi behaviour.

No. With a beat bank the boioers output goes straiught to the DHW draw off.
This si noit the case with a vented or unvented cylinder.

No it doesn't. With a vented or unvented cylinder, the boiler energy
is fed through a coil in the cylinder to heat the DHW in the cylinder.
A heatbank can be indirect or direct. In the indirect case, the
boiler heats a coil in the cylinder in the same way, but the water is
then pumped through a stainless steel heat exchanger to heat the DHW.
In the direct case the cylinder water passes through the boiler but
is still used via the stainless steel heat exchanger to heat the DHW.

..


The only real difference is that in the
heatbank case you have stored 25%
more energy in a given volume or a
small reduction in space.

You don't understand.

I understand perfectly, thanks.




Yes, and unvented cylinders do not have very large coils.

That depends on what you order and from whom.

Again.. unvented cylinders do not have very large coils.

Rubbish. If you order one with a substantial coil, you get one with a
substantial coil. That's exactly what I did. I had the
manufacturer install a pocket for a temperature probe and extra
fittings as well.

You should have fitted a heat bank and then it would be easy to


However, the match of a direct heatbank to a more sophisticated
condensing boiler is not a good one, and this does not leave any
significant advantages for the heat bank, unless one is really tight
on space.

A smart condenser will work well with a heat bank. A heat bank with the
top
half at 76-80C for DHW and the bottom at 45C for UFH works very well with
condensers. A diverter valve sends the boilers output to either section.

We've already had this discussion and I illustrated why this would not
be the case. I'm not going to go over the same ground again.

You don't understand.

Sorry to burst your bubble, but I understand completely.






---

..andy

To email, substitute .nospam with .gl

"Andy Hall" wrote in message
...

Provided that the cylinder is large enough,
which takes us back to the
point that it is only as good as the
energy stored plus the energy
that can be delivered into the heatbank
from the boiler while the
former is delivering energy to the
heat exchanger.

No. The system acts like a combi as a fall back.

Sure, but the performance level will have dropped off.

The point is you "never" run out of hot water.
Your hot water is 2 stage of high flow and
then low flow.

That's fine if you find that type of
performance acceptable.

Just about everyone with common sense would find it acceptable. You have
enough high flow water, then if you do run out of high flow your fallback to
a low flow. Never run out.

I would prefer to see the cylinder
adequately sized regardless of
whether it is used in a conventional
way or as a heatbank.

What makes you think it would not provide enough hot water?

No. With a beat bank the boilers output goes straight to the DHW draw
off.
This is not the case with a vented or unvented cylinder.

No it doesn't. With a vented or unvented cylinder, the boiler energy
is fed through a coil in the cylinder to heat the DHW in the cylinder.
A heatbank can be indirect or direct. In the indirect case, the
boiler heats a coil in the cylinder in the same way, but the water is
then pumped through a stainless steel heat exchanger to heat the DHW.
In the direct case the cylinder water passes through the boiler but
is still used via the stainless steel heat exchanger to heat the DHW.

failed!

The only real difference is that in the
heatbank case you have stored 25%
more energy in a given volume or a
small reduction in space.

You don't understand.

I understand perfectly, thanks.

You don't. failed!

Yes, and unvented cylinders do not have very large coils.

That depends on what you order and from whom.

Again.. unvented cylinders do not have very large coils.

Rubbish. If you order one with a substantial coil, you get one with a
substantial coil. That's exactly what I did. I had the
manufacturer install a pocket for a temperature probe and extra
fittings as well.

Coils in unvented cylinder are never as large as vented because if a large
boiler heated up the cylinder from cold it would create too much pressure in
the cylinder and the pressure relief controls would cut in. The Telford
Tornado is "trickle" charged.



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On Thu, 7 Aug 2003 08:59:42 +0100, "IMM" wrote:


"Andy Hall" wrote in message
.. .
On Wed, 6 Aug 2003 23:25:04 +0100, "IMM" wrote:

Rubbish. If you order one with a substantial coil, you get one with
a
substantial coil. That's exactly what I did. I had the
manufacturer install a pocket for a temperature probe and extra
fittings as well.

Coils in unvented cylinder are never
as large as vented because if a
large boiler heated up the cylinder
from cold it would create too much pressure
in the cylinder and the pressure relief
controls would cut in. The Telford
Tornado is "trickle" charged.

With a trapped air pocket??

yes.

I was not talking about this cylinder, but what it is possible to
order.

The Tornado is typical.

Pointless remark. I simply listed what *can* be ordered, not what is
typical.

Andy, why do you persist in taking a stance in a field you little about?

I'm not taking any stances because I have no need to do so.

I have simply related what I know to be the case because I have done
it.


..andy

To email, substitute .nospam with .gl

"Andy Hall" wrote in message
...
On Thu, 7 Aug 2003 08:59:42 +0100, "IMM" wrote:


"Andy Hall" wrote in message
.. .
On Wed, 6 Aug 2003 23:25:04 +0100, "IMM" wrote:

Rubbish. If you order one with a substantial coil, you get one
with
a
substantial coil. That's exactly what I did. I had the
manufacturer install a pocket for a temperature probe and extra
fittings as well.

Coils in unvented cylinder are never
as large as vented because if a
large boiler heated up the cylinder
from cold it would create too much pressure
in the cylinder and the pressure relief
controls would cut in. The Telford
Tornado is "trickle" charged.

With a trapped air pocket??

yes.

I was not talking about this cylinder, but what it is possible to
order.

The Tornado is typical.

Pointless remark. I simply listed what *can* be ordered, not what is
typical.

Andy, why do you persist in taking a stance in a field you little about?

I'm not taking any stances because I have no need to do so.

I have simply related what I know to be the case because I have done
it.

You haven't done it. You don't have a heat bank!! Gosh!!


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On Thu, 7 Aug 2003 16:21:25 +0100, "IMM" wrote:



Pointless remark. I simply listed what *can* be ordered, not what is
typical.

Andy, why do you persist in taking a stance in a field you little about?

I'm not taking any stances because I have no need to do so.

I have simply related what I know to be the case because I have done
it.

You haven't done it. You don't have a heat bank!! Gosh!!

I was not talking about that, I was talking about HW cylinders, as you
well know.

It is quite possible to order a pressurised type of cylinder with a
fast recovery heat exchanger . I have done that. Would you like
me to email you the receipt?

Do you have a heatbank, BTW?

..andy

To email, substitute .nospam with .gl

"IMM" wrote:

"Richard" wrote in message
snip

"IMM" wrote:
It is not quick recovery. It is a standard cylinder. Part L is the new
better standard. With a quick recovery you could have got away with a 150
litre cylinder and maybe a 125. Quick recovery are cheaper to run as the
boiler is operating more efficiently.


Why don't you read before you ramble. I said it was NOT a quick
recovery cylinder, just better than the old ones. Anyway does it
really matter if I can 'get away' with a 150l or 125l if I have the
cupboard space going begging. Further if I fill a 250 litre bath with
taps full on, do I really have enough hot water in 125l
Richard

On Sat, 9 Aug 2003 23:53:56 +0100, "IMM" wrote:


"Richard" wrote in message
.. .
"IMM" wrote:

"Richard" wrote in message
snip

"IMM" wrote:
It is not quick recovery. It is a standard cylinder. Part L is the new
better standard. With a quick recovery you could have got away with a
150
litre cylinder and maybe a 125. Quick recovery are cheaper to run as the
boiler is operating more efficiently.


Why don't you read before you ramble. I said it was NOT a quick
recovery cylinder, just better than the old ones. Anyway does it
really matter if I can 'get away' with a 150l or 125l if I have the
cupboard space going begging. Further if I fill a 250 litre bath with
taps full on, do I really have enough hot water in 125l

A 150 yes, and you would save a lot of money in running costs.

THat's rubbish as well. The heat loss through even a standard Part L
cylinder is de minimis. The difference between a 150 litre and, say,
a 200litre is not even worth discussing.




---

..andy

To email, substitute .nospam with .gl

"Andy Hall" wrote in message
...
On Sat, 9 Aug 2003 23:53:56 +0100, "IMM" wrote:


"Richard" wrote in message
.. .
"IMM" wrote:

"Richard" wrote in message
snip

"IMM" wrote:
It is not quick recovery. It is a standard cylinder. Part L is the
new
better standard. With a quick recovery you could have got away with a
150
litre cylinder and maybe a 125. Quick recovery are cheaper to run as
the
boiler is operating more efficiently.


Why don't you read before you ramble. I said it was NOT a quick
recovery cylinder, just better than the old ones. Anyway does it
really matter if I can 'get away' with a 150l or 125l if I have the
cupboard space going begging. Further if I fill a 250 litre bath with
taps full on, do I really have enough hot water in 125l

A 150 yes, and you would save a lot of money in running costs.

THat's rubbish as well. The heat loss through even a standard Part L
cylinder is de minimis. The difference between a 150 litre and, say,
a 200litre is not even worth discussing.

Although less standing heat losses, no one is on about this point. A quick
recovery rakes all the boilers heat with boiler cycling.



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"Bjorn" wrote in message
om...
OK, thanks for all the good advice. I have decided to go for a new
condensing system boiler with a new fast recovery cylinder and a pump
sited by the hot water tank. Just a few more questions.

Condensing System Boilers - Any reccommendations ? As said before
leaning towards Vaillant Ecomax range or Keston Celsius 25 - Comments
? Re Vaillant, how do I calculate KW rating needed ? (House is large
Victorian 4 bed with one bathroom possible extra shower in future)
Existing boiler is sited on exterior wall in bathroom, one floor below
HW tank, considering moving to floor below. Will efficiency be
affected ?

Fast Recovery HW Tank - Reccommendations ? Existing tank is 117
litres. How big should I go ? Have room for bigger. (Sorry , don't
want to start any more arguments).

80 litres will do for a quick recovery to replace the 117 litre British
Standard. Telford Typhoon is £100 from Travis Perkins. A good deal.
http://www.telford-group.com/typhoon.htm

Pump - reccommendations ? How noisy ? tactics for reducing noise ?
Twin/single, negative head, what does it all mean ?

If you insist on a pump (poor move) then you should go for the up market
brands. Cheap pumps can't hack it. For e.g., a Stuart Turner will be
£200-250 plus fittings, surrey flange etc. Consider getting a combi and
running your shower only through the combi water section to give high
pressure showers, and on the heating side of the combi treat as a normal
system boiler. This way, no noisy vibrating pump and cheaper into the
bargain too. BTW, I am no DIYer, take what I say very seriously.

Also anyone got Hansgrohe shower ? Do you like it ?

I have and they are very good.

From Discounted web site. As you see there is no difference between the
combi and the system boilers in price.

Ideal Icos M3080 System Boiler
Fan Flued System Condensing Boiler.

BTU's - 30 - 80,000

685mm High
390mm Wide
278mm Deep

Price Includes Flue & Delivery.

Price ex VAT: £630.00 £740.25 Including VAT at 17.5%

Ideal Isar
Price Includes Boiler - Flue Kit - Delivery

Fan Flued Condensing Combination Boiler.

The Isar is an automatically controlled, fanned flue
high-efficiency boiler.
The boiler modulates its heat to suit the demands of the heating
load, it
incorporates the variable thermostat for centeral heating
temperature
control, adjustable from 50 to 82C.
The use of the pre-mix burner allows control of gas input to the
appliance
to be directly linked to the fan speen. So, as the reduces speed
to match
heating load, the gas valve maintains the corrcet proportional
flow ensuring
a high boiler efficiency throughout its output range.

Output - 30,000 - 100,000 BTU's (8.9 - 29.3kW)

Compact Dimensions:-
685mm High
390mm Wide
278mm Deep

Flue Diameter - 100mm

Max Lift Weight - 43kg


Price ex VAT: £630.00 £740.25 Including VAT at 17.5%








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