Hi,

I am about to have a new heating system installed in my house. The
choice of boilers seem to come down to either a Worcester-Bosch
Highflow 400 or a Vokera Linea Max. As both of these boilers are
about the same price and have very similar specifications is there
much to choose between them? I would be interested in any independent
reliability surveys or comparative maintenance costs.

I know neither of these boilers are condensing but I can't find a
similar condensing boiler and also the vent will be very close to a
boundry so a plume might be unpopular with the neighbours.

TIA, W.

"W" wrote in message
...
Hi,

I am about to have a new heating system installed in my house. The
choice of boilers seem to come down to either a Worcester-Bosch
Highflow 400 or a Vokera Linea Max. As both of these boilers are
about the same price and have very similar specifications is there
much to choose between them? I would be interested in any independent
reliability surveys or comparative maintenance costs.

I know neither of these boilers are condensing but I can't find a
similar condensing boiler and also the vent will be very close to a
boundry so a plume might be unpopular with the neighbours.

From feedback the Highflow is pretty reliable and it has been around for a
quite a few years now. Assuming a condesning boiler is out because of the
plume, try an Alpha CB50. Approx the same performance as the High but wall
mounted.

The Worcester Bosch 40kW Greenstar condensing combi gives about 16
litres/min flow whereas the Highflow is about 18, as is the CB50.

The Highflow, Vokera and CB50 are all two stage flow rates. High flows when
the store is full of hot water and low flow, about the same as an avearge
combi, when exhausted. The recovery rate on all is v good; a matter a few
minutes.

Look at the Potterton Powermax http://www.powermax.co.uk. A boiler and
unvented cylinder all in one floor munted case. As with the Gledhill
Gulfstream 2000 is similar except it uses a heat bank like the Highflow and
Vokera. http://www.gledhill.net

On Sat, 25 Sep 2004 08:50:44 +0100, W
wrote:

Hi,

I am about to have a new heating system installed in my house. The
choice of boilers seem to come down to either a Worcester-Bosch
Highflow 400 or a Vokera Linea Max. As both of these boilers are
about the same price and have very similar specifications is there
much to choose between them? I would be interested in any independent
reliability surveys or comparative maintenance costs.

I know neither of these boilers are condensing but I can't find a
similar condensing boiler and also the vent will be very close to a
boundry so a plume might be unpopular with the neighbours.

TIA, W.

Who is suggesting the choice? Quoting installers?

Both are reputable makes, but neither is an exciting product from the
performance point of view. Although marketed as "suitable for the
larger house", really the power levels of 24-28kW are very average
these days. That is not to say that you necessarily need anything
larger but rather that there is plenty of choice in this range and
above.

Both are right at the very bottom of the legal limit on what is
allowed for new boiler installations - 78% on the SEDBUK seasonaly
efficiency scale. Condensing boilers achieve around 90-91%
efficiency, and from my own experience, the cost savings line up with
the efficiency difference.
Bear in mind that gas prices are in the process of increasing and the
trend will undoubtedly continue. If you plan to remain in the house
for a while, you will recover your costs.

Pluming on newer designs of condensing boiler are nowhere near the
level of earlier designs and on many models it is possible to use flue
systems constructed from 50mm high temperature PVC waste pipe. These
can be run some distance - even internally - and hence exhaust to a
more convenient place.

You haven't said much about your requirements.

Since it is a large house, do you have two bathrooms/showers and do
you need to use them concurrently?

Are you using a storage system currently?

Do you desperately need to save the cylinder and tank space?

There are some things to be careful about here.

Mains pressure hot water can be good, but it's essential to check that
the mains can deliver a good flow rate. Try measuring with a bucket
and stop watch at the kitchen tap. As a rule of thumb, if you get 20
litres/minute or more then a mains system can perform well, if it's in
the 9-12 range then it will be very poor and you may need to look at
(can be expensively) having the service pipe from the road increased
in size.

Having the water heated instantly in a simple combi means that the hot
water flow is limited to the instant energy is limited to that
provided by the burner. With the 24 and 28kW figures that you have
mentioned, this would be 9 and 11 litres per minute when the water is
cold in the winter, delivered at bath/shower temperature of 40
degrees. This is poor for one bath/shower and hopeless for two.

To get around it, both products you mention have a small heatbank
store of around 50-60 litres. This energy is applied rapidly to
the cold water passing through the boiler and allows the manufacturers
to quote impressive flow rates of 18 litres per minute. At 60 degrees
output and mixed with cold water, this will provide good flows for two
showers.

However, there is a catch. That is that once the little heatbank
runs out, the performance drops to the instantaneous rate and you are
very limited. With the volumes listed, you will be able to fill a
bath, not very deeply before the store runs out - approx 100 litres
total. A reasonable bath needs closer to 150 litres.
Two showers will run for a very few minutes on it if run together.

The manufacturers have not been dishonest if you read the small print
of the data sheets - they do say that the flow drops - but they also
use an average to optimistic mains temperature of 10 degrees. In the
winter, around 5 is more typical and that is probably when you want a
greater HW production rate. So the reality is not as good as the
brochures imply.

The only ways around this are to have a much larger boiler - you can
get 46kW instantaneous ones which will deliver around 18 litres/minute
at 40 degrees - or you need to increase the storage.

If you like the idea of mains pressure water, and can spare the
cylinder space, then a heatbank can be a good idea. These replace
the cylinder and you can get rid of the loft tank. The concept is
roughly like that in the Heatflow, but you can have a store of say
three times the size and obviously that makes a huge difference if
your demands are for two bathrooms. This idea also allows you to
have a wall mount or otherwise smaller boiler and gain space where it
is installed. For that matter the boiler could easily go somewhere
else entirely.

A pressurised hot water cylinder is another approach, and that would
have a similar improving effect.

Otherwise, if the mains water rate is poor, a storage system with loft
tank will perform better than a mains one and you can increase
pressure for a shower with a pump.

There are plenty of boilers around to cover all of these cases, so
don't get sucked into something that is not a good match for your
requirements.





..andy

To email, substitute .nospam with .gl

In message , Andy Hall
writes
On Sat, 25 Sep 2004 08:50:44 +0100, W
wrote:

Hi,

I am about to have a new heating system installed in my house. The
choice of boilers seem to come down to either a Worcester-Bosch
Highflow 400 or a Vokera Linea Max. As both of these boilers are
about the same price and have very similar specifications is there
much to choose between them? I would be interested in any independent
reliability surveys or comparative maintenance costs.
snip

There are plenty of boilers around to cover all of these cases, so
don't get sucked into something that is not a good match for your
requirements.

You forgot the very good suggestion of just having 2 or 3 combis.......

You know it makes sense :-)
--
Chris French, Leeds

"Andy Hall" wrote in message
...
On Sat, 25 Sep 2004 08:50:44 +0100, W
wrote:

Hi,

I am about to have a new heating system installed in my house. The
choice of boilers seem to come down to either a Worcester-Bosch
Highflow 400 or a Vokera Linea Max. As both of these boilers are
about the same price and have very similar specifications is there
much to choose between them? I would be interested in any independent
reliability surveys or comparative maintenance costs.

I know neither of these boilers are condensing but I can't find a
similar condensing boiler and also the vent will be very close to a
boundry so a plume might be unpopular with the neighbours.

TIA, W.

Who is suggesting the choice? Quoting installers?

Both are reputable makes, but neither
is an exciting product from the
performance point of view.

18019 litres/min is not bad at all amnd will fill a bath pronto.

Although marketed as "suitable for the
larger house", really the power levels
of 24-28kW are very average
these days.

Thye both use heated stored water, a heat bank, to boost performance.

That is not to say that you necessarily need anything
larger but rather that there is plenty of choice in this range and
above.

Both are right at the very bottom of the legal limit on what is
allowed for new boiler installations - 78% on the SEDBUK seasonaly
efficiency scale.

He said he has doubts about the condensing plume.

Condensing boilers achieve around 90-91%
efficiency, and from my own experience, the cost savings line up with
the efficiency difference.
Bear in mind that gas prices are in the process of increasing and the
trend will undoubtedly continue. If you plan to remain in the house
for a while, you will recover your costs.

Pluming on newer designs of condensing boiler are nowhere near the
level of earlier designs and on many models it is possible to use flue
systems constructed from 50mm high temperature PVC waste pipe. These
can be run some distance - even internally - and hence exhaust to a
more convenient place.

He is after a combi, no condensing combi I know eliminates the plume.

Having the water heated instantly
in a simple combi means that the hot
water flow is limited to the instant
energy is limited to that
provided by the burner.

He stated two stored water excellent flow combi's, not simple low flow low
models.

To get around it, both products you mention have a small heatbank
store of around 50-60 litres. This energy is applied rapidly to
the cold water passing through the boiler and allows the manufacturers
to quote impressive flow rates of 18 litres per minute. At 60 degrees
output and mixed with cold water, this will provide good flows for two
showers.

However, there is a catch. That is that once the little heatbank
runs out, the performance drops to the instantaneous rate and you are
very limited.

He is running a house not a school. It will very rare will drop into the
low flow stage of the combi's. But he will "never" run out hot water. The
recovery rate of these models is only a few minutes.

With the volumes listed, you will be able to fill a
bath, not very deeply before the store runs out - approx 100 litres
total.

100 litres is the average bath size. Any more water and it fill at the lower
flowrate of combi. this can be running while people are actually in the
bath, as many people,do anyhow. They can in when there is only a few inches
of water and leave the taps on.

A reasonable bath needs closer to 150 litres.
Two showers will run for a very few minutes
on it if run together.

Average shower of 7 - 8 litres/minute at approx 40C. So 2 showers will take
15 litres of mixed water. Of the 15 litres 2/3 to 3/4 will be hot and the
rest cold of the 60C draw-off temperature, so only 10 litres/min will be
drawn off the 60 litre 80C temperature stored water heat bank. Then you have
to take into account that on draw-off the heat bank always fires up
providing approx 11 litres/min. In effect the stored water supplies one
shower, the instant side doing more than the other. As the instant side is
infinite and never runs out, the stored water alone will provide one of the
showers. The 60 litres at 80C will keep one shower running for about 13
minutes. So, two average shower will run simultaneously for approx 13 - 15
minutes, not a few minutes.

Please do not give opinions of equipment you have even seen never mind seen
them in action. Those I have met who have these sort of combi's love them
and would never go back to tank/cylinder/power shower pump dross. The poster
is attempting gain information to make a reasoned decision. The last thing
he needs is misinformation from an amateur.

"chris French" wrote in message
...
In message , Andy Hall
writes
On Sat, 25 Sep 2004 08:50:44 +0100, W
wrote:

Hi,

I am about to have a new heating system installed in my house. The
choice of boilers seem to come down to either a Worcester-Bosch
Highflow 400 or a Vokera Linea Max. As both of these boilers are
about the same price and have very similar specifications is there
much to choose between them? I would be interested in any independent
reliability surveys or comparative maintenance costs.
snip

There are plenty of boilers around to cover all of these cases, so
don't get sucked into something that is not a good match for your
requirements.

You forgot the very good suggestion of just having 2 or 3 combis.......

You know it makes sense :-)

Quite right.

Highly cost effective and gives a high flowrate and should always be
considered. Two Worcester Juniors can be had for approx £1100, not far from
he cost of one Highflow or one Vokera. Combined they will give approx 21
litres/min flowrate. They give natural zoning with no complex wiring or
zone valves. One does upstairs CH One does the downstairs CH. each has its
own programmer stat.

A doddle to fit, a doddle to wire up, cheap, CH zoning, high flowrates and
backup if one goes down. A win, win, all the way. Must be considered in
these situations.

On Sat, 25 Sep 2004 14:08:25 +0100, chris French
wrote:

In message , Andy Hall
writes
On Sat, 25 Sep 2004 08:50:44 +0100, W
wrote:

Hi,

I am about to have a new heating system installed in my house. The
choice of boilers seem to come down to either a Worcester-Bosch
Highflow 400 or a Vokera Linea Max. As both of these boilers are
about the same price and have very similar specifications is there
much to choose between them? I would be interested in any independent
reliability surveys or comparative maintenance costs.
snip

There are plenty of boilers around to cover all of these cases, so
don't get sucked into something that is not a good match for your
requirements.

You forgot the very good suggestion of just having 2 or 3 combis.......

You know it makes sense :-)


You're right. A win-win or win-win-win situation. ;-)
..andy

To email, substitute .nospam with .gl

On Sat, 25 Sep 2004 08:50:44 +0100, W
wrote:

Hi,

I know neither of these boilers are condensing but I can't find a
similar condensing boiler and also the vent will be very close to a
boundry so a plume might be unpopular with the neighbours.

Hi,

Why not talk to you neighbours and explain about condensing boilers
and plumes, they might not mind after all. A condensing boiler
condenses out most of chemicals in the flue gases, unlike a
conventional boiler. If it does turn out that they don't like it, the
flue can be resited easily with a lot of boilers.

cheers,
Pete.

"Pete C" wrote in message
...
On Sat, 25 Sep 2004 08:50:44 +0100, W
wrote:

Hi,

I know neither of these boilers are condensing but I can't find a
similar condensing boiler and also the vent will be very close to a
boundry so a plume might be unpopular with the neighbours.

Hi,

Why not talk to you neighbours and explain about condensing boilers
and plumes, they might not mind after all. A condensing boiler
condenses out most of chemicals in the flue gases, unlike a
conventional boiler. If it does turn out that they don't like it, the
flue can be resited easily with a lot of boilers.

They may say OK, and then onjcet whe they see the plume.

On Sat, 25 Sep 2004 14:40:07 +0100, "IMM" wrote:


"Andy Hall" wrote in message
.. .
On Sat, 25 Sep 2004 08:50:44 +0100, W
wrote:

Hi,

I am about to have a new heating system installed in my house. The
choice of boilers seem to come down to either a Worcester-Bosch
Highflow 400 or a Vokera Linea Max. As both of these boilers are
about the same price and have very similar specifications is there
much to choose between them? I would be interested in any independent
reliability surveys or comparative maintenance costs.

I know neither of these boilers are condensing but I can't find a
similar condensing boiler and also the vent will be very close to a
boundry so a plume might be unpopular with the neighbours.

TIA, W.

Who is suggesting the choice? Quoting installers?

Both are reputable makes, but neither
is an exciting product from the
performance point of view.

18019 litres/min is not bad at all amnd will fill a bath pronto.

It would be outstanding, but not all that likely from a 24kW boiler
and domestic water supply. Are you going to contact Thames Water
to arrange for a 60cm supply pipe?



Although marketed as "suitable for the
larger house", really the power levels
of 24-28kW are very average
these days.

Thye both use heated stored water, a heat bank, to boost performance.

That is not to say that you necessarily need anything
larger but rather that there is plenty of choice in this range and
above.

Both are right at the very bottom of the legal limit on what is
allowed for new boiler installations - 78% on the SEDBUK seasonaly
efficiency scale.

He said he has doubts about the condensing plume.

I covered that.


Condensing boilers achieve around 90-91%
efficiency, and from my own experience, the cost savings line up with
the efficiency difference.
Bear in mind that gas prices are in the process of increasing and the
trend will undoubtedly continue. If you plan to remain in the house
for a while, you will recover your costs.

Pluming on newer designs of condensing boiler are nowhere near the
level of earlier designs and on many models it is possible to use flue
systems constructed from 50mm high temperature PVC waste pipe. These
can be run some distance - even internally - and hence exhaust to a
more convenient place.

He is after a combi, no condensing combi I know eliminates the plume.

There is, however a range of effects.

Even a conventional boiler will produce a plume on cold dry days.



Having the water heated instantly
in a simple combi means that the hot
water flow is limited to the instant
energy is limited to that
provided by the burner.

He stated two stored water excellent flow combi's, not simple low flow low
models.

I'm aware of that, which is why I said "in a" and not in "the ones
that were mentioned". I then went on to discuss the effect of
adding a small store.


To get around it, both products you mention have a small heatbank
store of around 50-60 litres. This energy is applied rapidly to
the cold water passing through the boiler and allows the manufacturers
to quote impressive flow rates of 18 litres per minute. At 60 degrees
output and mixed with cold water, this will provide good flows for two
showers.

However, there is a catch. That is that once the little heatbank
runs out, the performance drops to the instantaneous rate and you are
very limited.

He is running a house not a school. It will very rare will drop into the
low flow stage of the combi's. But he will "never" run out hot water. The
recovery rate of these models is only a few minutes.

The storage capacity is very limited as was demonstrated last week.

No specifics on what "large house" meant, or indeed the numbr of
bathrooms and pattern of use. I therefore described what could
happen under patterns of use that are entirely possible in a large,
but not that large house. it is possible that two bathrooms are in
use simultaneously and peak demands are high. I certainly have that
situation, and it is not at all unusual.

Obviously if the OP's needs are less, then the situation will be
better and a small store combi may be OK.

I have simply stated what could happen under quite possible
circumstances, not hoped that it won't.

With the volumes listed, you will be able to fill a
bath, not very deeply before the store runs out - approx 100 litres
total.

100 litres is the average bath size.


It's a small bath. We already covered that, and I am not getting into
another pantomime argument about it.

Any more water and it fill at the lower
flowrate of combi. this can be running while people are actually in the
bath, as many people,do anyhow. They can in when there is only a few inches
of water and leave the taps on.

That makes no sense in English at all.


A reasonable bath needs closer to 150 litres.
Two showers will run for a very few minutes
on it if run together.

Average shower of 7 - 8 litres/minute at approx 40C.

That is not an average shower at all. It is in the range of a poor
electric shower. We covered that already.

So 2 showers will take
15 litres of mixed water.

It needs at least twice that.


Of the 15 litres 2/3 to 3/4 will be hot and the
rest cold of the 60C draw-off temperature,

That is optimistic if you do the actual calculations as we did only
last week.

so only 10 litres/min will be
drawn off the 60 litre 80C temperature stored water heat bank.

So even in the best case that you describe, it lasts 6 minutes. In
reality, it lasts for closer to half of that.


Then you have
to take into account that on draw-off the heat bank always fires up
providing approx 11 litres/min.

In the 28kW model. In the 24kW model, it's 9.

In effect the stored water supplies one
shower, the instant side doing more than the other.

In reality, it is still way short, because the premise of 7-8lpm is
erroneous in the first place.

As the instant side is
infinite and never runs out, the stored water alone will provide one of the
showers. The 60 litres at 80C will keep one shower running for about 13
minutes.

At what usage rate?

The 80 degree water is used via a heat exchanger, but to simplify
matters, let's assume 100% efficiency and "mix" that with 5 degree
mains cold water.

Using

Vc[Tf-Tc] = Vh[Th-Tf]

where

Vc = cold volume
Vh = hot volume
Tf = mixed water temperature
Th = hot temperature
Tc = cold temperature

produces

Vc[40-5] = 60[80-40]

Solving for Vc gives

Vc = 68.6 litres

Adding Vh back in to give the volume at 40 degrees gives 128.6 litres.

To achieve a 13 minute run before freezing ones bits would require a
flow rate of no more than 9.8 lpm maximum.

At the more realistic 15lpm, the run time will be 8.5mins max.

If there are females in the house who wash their hair in the shower,
there are going to be tears.



So, two average shower will run simultaneously for approx 13 - 15
minutes, not a few minutes.

Both can run at a poor rate of 8lpm or one at that and one for 8
minutes properly. This is a few minutes.

It also pays no account of what would happen if a bath is taken in one
bathroom. Then the situation is dire.



Please do not give opinions of equipment you have even seen never mind seen
them in action.

In English?

Before buying anything, one should look at the technical specification
and certainly past the marketing. It is only possible for a product
to perform as well as physics allows.

I haven't said that these products are totally useless or
inapplicable, simply that as a result of the design limitations, there
is a limit to the performance.

That may be acceptable to some people, but it does need to be pointed
out that there can easily be scenarios where the results will be
disappointing. In some households people are willing to alter their
patterns of use to fit in with the limitations of the equi[pment.
Others can't, and then a limited solution like this is not going to
work for them. It's completely irrelevant whether I have one of
these or not. The performance is totally predictable with simple
arithmetic.

You should look at the actual specifications and not the marketing
hype.


Those I have met who have these sort of combi's love them
and would never go back to tank/cylinder/power shower pump dross.

I am sure that there are. Either their usage patterns fall within
what this type of device can do or they have altered their usage
pattern to fit the system.

Some people won't find that acceptable, and it is more likely that
that will be in a larger property with multiple bathrooms and lots of
people.



The poster
is attempting gain information to make a reasoned decision. The last thing
he needs is misinformation from an amateur.

So why are you giving it?


..andy

To email, substitute .nospam with .gl

"Andy Hall" wrote in message
...
On Sat, 25 Sep 2004 14:40:07 +0100, "IMM" wrote:


"Andy Hall" wrote in message
.. .
On Sat, 25 Sep 2004 08:50:44 +0100, W
wrote:

Hi,

I am about to have a new heating system installed in my house. The
choice of boilers seem to come down to either a Worcester-Bosch
Highflow 400 or a Vokera Linea Max. As both of these boilers are
about the same price and have very similar specifications is there
much to choose between them? I would be interested in any independent
reliability surveys or comparative maintenance costs.

I know neither of these boilers are condensing but I can't find a
similar condensing boiler and also the vent will be very close to a
boundry so a plume might be unpopular with the neighbours.

TIA, W.

Who is suggesting the choice? Quoting installers?

Both are reputable makes, but neither
is an exciting product from the
performance point of view.

18019 litres/min is not bad at all amnd will fill a bath pronto.

It would be outstanding,

I don't think he wants, or needs, firehose volumes and pressures.

Although marketed as "suitable for the
larger house", really the power levels
of 24-28kW are very average
these days.

Thye both use heated stored water, a heat bank, to boost performance.

That is not to say that you necessarily need anything
larger but rather that there is plenty of choice in this range and
above.

Both are right at the very bottom of the legal limit on what is
allowed for new boiler installations - 78% on the SEDBUK seasonaly
efficiency scale.

He said he has doubts about the condensing plume.

I covered that.


Condensing boilers achieve around 90-91%
efficiency, and from my own experience, the cost savings line up with
the efficiency difference.
Bear in mind that gas prices are in the process of increasing and the
trend will undoubtedly continue. If you plan to remain in the house
for a while, you will recover your costs.

Pluming on newer designs of condensing boiler are nowhere near the
level of earlier designs and on many models it is possible to use flue
systems constructed from 50mm high temperature PVC waste pipe. These
can be run some distance - even internally - and hence exhaust to a
more convenient place.

He is after a combi, no condensing combi I know eliminates the plume.

There is, however a range of effects.

Even a conventional boiler will produce a plume on cold dry days.

Only slight.

Having the water heated instantly
in a simple combi means that the hot
water flow is limited to the instant
energy is limited to that
provided by the burner.

He stated two stored water excellent flow combi's, not simple low flow
low
models.

I'm aware of that, which is why I said "in a" and not in "the ones
that were mentioned". I then went on to discuss the effect of
adding a small store.

To get around it, both products you mention have a small heatbank
store of around 50-60 litres. This energy is applied rapidly to
the cold water passing through the boiler and allows the manufacturers
to quote impressive flow rates of 18 litres per minute. At 60 degrees
output and mixed with cold water, this will provide good flows for two
showers.

However, there is a catch. That is that once the little heatbank
runs out, the performance drops to the instantaneous rate and you are
very limited.

He is running a house not a school. It will very rare will drop into the
low flow stage of the combi's. But he will "never" run out hot water.
The
recovery rate of these models is only a few minutes.

The storage capacity is very limited as was demonstrated last week.

You never.

No specifics on what "large house" meant, or indeed the numbr of
bathrooms and pattern of use. I therefore described what could
happen under patterns of use that are entirely possible in a large,
but not that large house. it is possible that two bathrooms are in
use simultaneously and peak demands are high. I certainly have that
situation, and it is not at all unusual.

Obviously if the OP's needs are less, then the situation will be
better and a small store combi may be OK.

I have simply stated what could happen under quite possible
circumstances, not hoped that it won't.

With the volumes listed, you will be able to fill a
bath, not very deeply before the store runs out - approx 100 litres
total.

100 litres is the average bath size.

It's a small bath.

100 litres is the average bath size!!!!!

Any more water and it fill at the lower
flowrate of combi. this can be running while people are actually in the
bath, as many people,do anyhow. They can in when there is only a few
inches
of water and leave the taps on.

That makes no sense in English at all.


A reasonable bath needs closer to 150 litres.
Two showers will run for a very few minutes
on it if run together.

Average shower of 7 - 8 litres/minute at approx 40C.

That is not an average shower at all.

It is an average shower!!!!!!!!!

So 2 showers will take
15 litres of mixed water.

It needs at least twice that.

So 2 showers will take 15 litres of mixed water!!!!!!!!!!

snip garbage

The poster
is attempting gain information to make a
reasoned decision. The last thing
he needs is misinformation from an amateur.

So why are you giving it?

Because I know what I am on about and you clearly do not.

On Sat, 25 Sep 2004 15:53:13 +0100, "IMM" wrote:




18019 litres/min is not bad at all amnd will fill a bath pronto.

It would be outstanding,

I don't think he wants, or needs, firehose volumes and pressures.

I'm sure. So your suggestion of over 18000 lpm is perhaps a touch on
the high side?



He is after a combi, no condensing combi I know eliminates the plume.

There is, however a range of effects.

Even a conventional boiler will produce a plume on cold dry days.

Only slight.

It can be only slight with a modern design of condensing boiler
especially on a longer flue, and in any case I suggested ways to
address any pluming issue.



The storage capacity is very limited as was demonstrated last week.

You never.

Would you like me to post a link to the thread where the numbers were
calculated?





100 litres is the average bath size.

It's a small bath.

100 litres is the average bath size!!!!!

It may be for you, but as I say, I am not getting into a pantomime
argument with Widow Twankey.




Average shower of 7 - 8 litres/minute at approx 40C.

That is not an average shower at all.

It is an average shower!!!!!!!!!

Again, it may be for you, etc. etc.




So 2 showers will take
15 litres of mixed water.

It needs at least twice that.

So 2 showers will take 15 litres of mixed water!!!!!!!!!!

No, that's one.



The poster
is attempting gain information to make a
reasoned decision. The last thing
he needs is misinformation from an amateur.

So why are you giving it?

Because I know what I am on about and you clearly do not.

Uh huh.


..andy

To email, substitute .nospam with .gl

"W" wrote in message
...
Hi,

I am about to have a new heating system installed in my house. The
choice of boilers seem to come down to either a Worcester-Bosch
Highflow 400 or a Vokera Linea Max. As both of these boilers are
about the same price and have very similar specifications is there
much to choose between them? I would be interested in any independent
reliability surveys or comparative maintenance costs.

I know neither of these boilers are condensing but I can't find a
similar condensing boiler and also the vent will be very close to a
boundry so a plume might be unpopular with the neighbours.

TIA, W.

I did a Google and here is a report from a user, Note the bath filling
performance.


"Paul J S Green" wrote in message
...
Thanks for the quick response Tony.

"TonyK" wrote in message

The bumph on the Highflow states that
there are 60 litres of stored hot
water (@ 80 degrees). Other posts indicate
that this, bled down with cold
water will last very well @ 18 litres/min.
What happens when the onboard
store runs out? I assume it will drop from
18 l/min down to normal combi
type performance?

That sounds about right although it does
appear to start replenishing the
tank as soon as a tap is switched on.

We've got a *big* single bath, nearly
a double. Fills that without any
problems.

So, does that mean it fills the bath quickly
with no hint of it running out
of hot water?

Certainly doesn't run out of hot water but takes quit a while to fill purely
because of its size.

In article ,
IMM wrote:
Average shower of 7 - 8 litres/minute at approx 40C.

That is not an average shower at all.

It is an average shower!!!!!!!!!

Only where you've specified the heating arrangments. Most people who wash
would like a better performance.

--
*Too many clicks spoil the browse *

Dave Plowman London SW
To e-mail, change noise into sound.

In article , Pete C
writes
On Sat, 25 Sep 2004 08:50:44 +0100, W
wrote:

Hi,

I know neither of these boilers are condensing but I can't find a
similar condensing boiler and also the vent will be very close to a
boundry so a plume might be unpopular with the neighbours.

Hi,

Why not talk to you neighbours and explain about condensing boilers
and plumes, they might not mind after all. A condensing boiler
condenses out most of chemicals in the flue gases, unlike a
conventional boiler. If it does turn out that they don't like it, the
flue can be resited easily with a lot of boilers.


Well tough if they do see the plume. Accept it, its energy efficiency in
action.....

--
Tony Sayer

On Sat, 25 Sep 2004 12:50:15 +0100, Andy Hall
wrote:

On Sat, 25 Sep 2004 08:50:44 +0100, W
wrote:

I am about to have a new heating system installed in my house. The
choice of boilers seem to come down to either a Worcester-Bosch
Highflow 400 or a Vokera Linea Max. As both of these boilers are
about the same price and have very similar specifications is there
much to choose between them? I would be interested in any independent
reliability surveys or comparative maintenance costs.

I know neither of these boilers are condensing but I can't find a
similar condensing boiler and also the vent will be very close to a
boundry so a plume might be unpopular with the neighbours.

TIA, W.

Who is suggesting the choice? Quoting installers?

Yes, and based on my limited research. Most fitters just want to put
a basic combi in due to cost but I am not sure it will suit our needs.

Both are reputable makes, but neither is an exciting product from the
performance point of view. Although marketed as "suitable for the
larger house", really the power levels of 24-28kW are very average
these days. That is not to say that you necessarily need anything
larger but rather that there is plenty of choice in this range and
above.

-- snip --

You haven't said much about your requirements.

Since it is a large house, do you have two bathrooms/showers and do
you need to use them concurrently?


Requirements a
* Hot water in two bathrooms (and kitchen)
* Possible simultaneous use of two showers or one shower and sink.
* Occasional baths that don't take 1/2 hour to fill.
* Powerful showers (not gravity).

I would prefer a condensing boiler just because of the better
efficiency. However I am not yet convinced that the extra cost of the
boiler will be recovered as quickly as many suggest. I've no idea how
long I will stay in my current house. It may be a few years or
longer.

Are you using a storage system currently?

We have an ancient system with tank and back boiler which has never
worked very well. It's only fit for the dump.

Do you desperately need to save the cylinder and tank space?

We are having modifications made to our house at the moment to gain an
extra bathroom (to make 2). One of the changes is that the existing
airing cupboard has to go. We may be able to find another location
for this, but I want to explore all the options at the moment. I'm
not set on a combi but I like the fact they appear to be cheaper than
a system with tank. I want to find out if the benefits of a different
system is worth the extra money.

Mains pressure hot water can be good, but it's essential to check that
the mains can deliver a good flow rate. Try measuring with a bucket
and stop watch at the kitchen tap. As a rule of thumb, if you get 20
litres/minute or more then a mains system can perform well, if it's in
the 9-12 range then it will be very poor and you may need to look at
(can be expensively) having the service pipe from the road increased
in size.

Mains pressure and flow seem to be fine. We get nearly 20 litres/min
but there are two stop cocks at the moment which I believe are
restricting the flow rate so we should be able to get more flow quite
easily.

-- snip --

If you like the idea of mains pressure water, and can spare the
cylinder space, then a heatbank can be a good idea. These replace
the cylinder and you can get rid of the loft tank. The concept is
roughly like that in the Heatflow, but you can have a store of say
three times the size and obviously that makes a huge difference if
your demands are for two bathrooms. This idea also allows you to
have a wall mount or otherwise smaller boiler and gain space where it
is installed. For that matter the boiler could easily go somewhere
else entirely.

I like the idea of a heatbank or cylinder but I don't have unlimited
funds and these options seem a lot more expensive. With whatever
system I get I want good value for money.

If I could get something similar to the highflow or linea max, but
with a slightly bigger store for not much more money I would probably
be happy :-)

Someone else on this thread suggested a gledhill gulfstream which
sounds good but I don't know where to get one or how much they cost.
I am not confident of fitting it myself so I need to find something
that a plumber/heating engineer will not charge a fortune for.

Cheers, W

On Sun, 26 Sep 2004 19:36:33 +0100, W
wrote:



I like the idea of a heatbank or cylinder but I don't have unlimited
funds and these options seem a lot more expensive. With whatever
system I get I want good value for money.

If I could get something similar to the highflow or linea max, but
with a slightly bigger store for not much more money I would probably
be happy :-)


Sounds as though a heatbank or pressurised cylinder in the in the loft
might be a good option.

Essentially you do away with the cylinder in the airing cupboard and
the roof tank and fit the heatbank/cylinder where the tank was.

http://www.albion-online.co.uk/stainless%20x.html

http://www.albion-online.co.uk/mainsflow%20x.html


You could also fit the boiler in the loft for that matter.
Perhaps that would help with flue location


..andy

To email, substitute .nospam with .gl

"Andy Hall" wrote in message
...
On Sun, 26 Sep 2004 19:36:33 +0100, W
wrote:



I like the idea of a heatbank or cylinder but I don't have unlimited
funds and these options seem a lot more expensive. With whatever
system I get I want good value for money.

If I could get something similar to the highflow or linea max, but
with a slightly bigger store for not much more money I would probably
be happy :-)


Sounds as though a heatbank or pressurised cylinder in the in the loft
might be a good option.

Essentially you do away with the cylinder in the airing cupboard and
the roof tank and fit the heatbank/cylinder where the tank was.

http://www.albion-online.co.uk/stainless%20x.html

http://www.albion-online.co.uk/mainsflow%20x.html


You could also fit the boiler in the loft for that matter.
Perhaps that would help with flue location

Or he could fit a high flow combi and save a ton of money.

On Sun, 26 Sep 2004 20:20:41 +0100, Andy Hall
wrote:

On Sun, 26 Sep 2004 19:36:33 +0100, W
wrote:

I like the idea of a heatbank or cylinder but I don't have unlimited
funds and these options seem a lot more expensive. With whatever
system I get I want good value for money.

If I could get something similar to the highflow or linea max, but
with a slightly bigger store for not much more money I would probably
be happy :-)

Sounds as though a heatbank or pressurised cylinder in the in the loft
might be a good option.

Essentially you do away with the cylinder in the airing cupboard and
the roof tank and fit the heatbank/cylinder where the tank was.

http://www.albion-online.co.uk/stainless%20x.html

http://www.albion-online.co.uk/mainsflow%20x.html

Can someone explain the pros/cons of the direct vs the indirect
mainsflow stores? What kind of boiler would suit which store? Can
they be placed in a cold area such as a garage?

You could also fit the boiler in the loft for that matter.
Perhaps that would help with flue location

I haven't found a fitter willing to lift a boiler into the roof space
yet!

W.

Well tough if they do see the plume. Accept it, its energy efficiency in
action.....

My Icos plumed a lot. It was actually quite annoying. The WB Greenstar
hardly plumes at all. However, this may have a lot to do with the Icos
having a short horizontal flue just below the bedroom window, whilst the WB
flue is longer and vertical through the roof, out of sight!

Christian.

I haven't found a fitter willing to lift a boiler into the roof space
yet!

Look harder!

Mine is in the loft and it is the best place for it!

To get anyone to quote, you'll need a boarded loft, electric light, a fixed
(but retractable if desired) loft ladder and hatch guarding. It is also
better with insulated rafters, rather than floor, to avoid any freezing
issues.

Also expect a larger bill unless you're going to be running the
cables/pipework yourself.

Christian.

On Mon, 27 Sep 2004 15:50:44 +0100, W
wrote:

On Sun, 26 Sep 2004 20:20:41 +0100, Andy Hall
wrote:

On Sun, 26 Sep 2004 19:36:33 +0100, W
wrote:

I like the idea of a heatbank or cylinder but I don't have unlimited
funds and these options seem a lot more expensive. With whatever
system I get I want good value for money.

If I could get something similar to the highflow or linea max, but
with a slightly bigger store for not much more money I would probably
be happy :-)

Sounds as though a heatbank or pressurised cylinder in the in the loft
might be a good option.

Essentially you do away with the cylinder in the airing cupboard and
the roof tank and fit the heatbank/cylinder where the tank was.

http://www.albion-online.co.uk/stainless%20x.html

http://www.albion-online.co.uk/mainsflow%20x.html

Can someone explain the pros/cons of the direct vs the indirect
mainsflow stores? What kind of boiler would suit which store? Can
they be placed in a cold area such as a garage?

An indirect unit allows you much more choice of boiler and the rest of
the system because the stored water is separate from the boiler
primary and fed from a smaller internal tank. You can use a sealed
primary system, for example, and choose virtually any boiler.


A direct unit is useful if you were going to use a conventional
boiler, which operates more optimally with long burns using the water
directly from the cylinder. The boiler side has to be run open
vented and that may have an impact on boiler choice as some require
pressurised operation. You could run the CH from the store as well
with a conventional boiler.

If you are going to use a condensing boiler, then an indirect store is
a better choice, with a hookup as shown in Albion's Indirect diagram.
This is because the boiler can modulate down to low power and best
efficiency when driving the radiators and full power for the cylinder
for the short period that it takes to heat the cylinder.

You could easily put this unit in a cold area - they are insulated.
In a garage, I'd probably build a small cupboard around it and
insulate that as well to further reduce heat loss.



You could also fit the boiler in the loft for that matter.
Perhaps that would help with flue location

I haven't found a fitter willing to lift a boiler into the roof space
yet!

Oh dear. Many are officially a two person lift, but I am sure that
most fitters manhandle them in kitchens on their own.

Perhaps you could rig up a winch over the loft hatch.....




W.

..andy

To email, substitute .nospam with .gl

"Andy Hall" wrote
| I haven't found a fitter willing to lift a boiler into the
| roof space yet!
| Oh dear. Many are officially a two person lift, but I
| am sure that most fitters manhandle them in kitchens on their
| own.
| Perhaps you could rig up a winch over the loft hatch.....

Or use a piston lift.


######
###### - boiler
######
######
--------
| |
| | - plywood boxes end-to-end to
|| || make piston
|| ||
| |
| = - cylinder of expanding foam
------


Owain

In article , Christian
McArdle writes
Well tough if they do see the plume. Accept it, its energy efficiency in
action.....

My Icos plumed a lot. It was actually quite annoying. The WB Greenstar
hardly plumes at all. However, this may have a lot to do with the Icos
having a short horizontal flue just below the bedroom window, whilst the WB
flue is longer and vertical through the roof, out of sight!

Christian.



Yep, and at this time of year more people are indoors and it gets dark
earlier.....
--
Tony Sayer

On Mon, 27 Sep 2004 20:51:15 +0100, "Owain"
wrote:

"Andy Hall" wrote
| I haven't found a fitter willing to lift a boiler into the
| roof space yet!
| Oh dear. Many are officially a two person lift, but I
| am sure that most fitters manhandle them in kitchens on their
| own.
| Perhaps you could rig up a winch over the loft hatch.....

Or use a piston lift.


######
###### - boiler
######
######
--------
| |
| | - plywood boxes end-to-end to
|| || make piston
|| ||
| |
| = - cylinder of expanding foam
------


Owain



Can you imagine what would happen if the box split or something else
went wrong?. It would make Peter Parry's canoe story sound like a
kids party.




..andy

To email, substitute .nospam with .gl

On Mon, 27 Sep 2004 16:57:24 +0100, Andy Hall
wrote:

An indirect unit allows you much more choice of boiler and the rest of
the system because the stored water is separate from the boiler
primary and fed from a smaller internal tank. You can use a sealed
primary system, for example, and choose virtually any boiler.

A direct unit is useful if you were going to use a conventional
boiler, which operates more optimally with long burns using the water
directly from the cylinder. The boiler side has to be run open
vented and that may have an impact on boiler choice as some require
pressurised operation. You could run the CH from the store as well
with a conventional boiler.

If you are going to use a condensing boiler, then an indirect store is
a better choice, with a hookup as shown in Albion's Indirect diagram.
This is because the boiler can modulate down to low power and best
efficiency when driving the radiators and full power for the cylinder
for the short period that it takes to heat the cylinder.

You could easily put this unit in a cold area - they are insulated.
In a garage, I'd probably build a small cupboard around it and
insulate that as well to further reduce heat loss.

Thank you for your answer. That's just the level of detail I was
looking for.

You could also fit the boiler in the loft for that matter.
Perhaps that would help with flue location

I haven't found a fitter willing to lift a boiler into the roof space
yet!

Oh dear. Many are officially a two person lift, but I am sure that
most fitters manhandle them in kitchens on their own.

Perhaps you could rig up a winch over the loft hatch.....

Before I was thinking of an all-in-one unit. I guess if I go for a
separate boiler and store they will be easier to lift. I guess a
modern condensing system boiler would be a good bet to go with the
indirect store.

BTW: Do most boilers have their controls integrated on the boiler or
are they available as a remote unit? I wouldn't want to have to go in
the loft every time I need to change a setting.

W.

"IMM" wrote in message
...

"W" wrote in message
...
Hi,

I am about to have a new heating system installed in my house. The
choice of boilers seem to come down to either a Worcester-Bosch
Highflow 400 or a Vokera Linea Max. As both of these boilers are
about the same price and have very similar specifications is there
much to choose between them? I would be interested in any independent
reliability surveys or comparative maintenance costs.

I know neither of these boilers are condensing but I can't find a
similar condensing boiler and also the vent will be very close to a
boundry so a plume might be unpopular with the neighbours.

TIA, W.

I did a Google and here is a report from a user, Note the bath filling
performance.


Er, yes. All subjective opinions with not a single quantifiable statement.
For example:

"We've got a big single bath, nearly a double" - No indication of actual
capacity.

"Fills that without any problems" - no reference to water temperature,
volume or time to fill.

"Certainly doesn't run out of hot water but takes quit a while to fill
purely because of its size." - again no reference to volume, temperature or
time taken.

So all you've provided is a set of statements from one person who is happy
with their installation, but that provide no means for anyone to make a
valid comparison against alternatives. Those statements are the sort of
meaningless endorsements found in marketing brochures, not quantifiable
metrics.

Cheers
Clive

On Tue, 28 Sep 2004 13:16:26 +0100, W
wrote:



Before I was thinking of an all-in-one unit. I guess if I go for a
separate boiler and store they will be easier to lift. I guess a
modern condensing system boiler would be a good bet to go with the
indirect store.

That would be a good choice.

Most wall-hung boilers weigh in the 35-45kg range so it really would
be a two person lift into a loft space or some kind of hoist.

You can download installation guides from most manufacturer web sites
which give all the details.

www.discountedheating.co.uk is useful because there are clickable
links for most products and you can go from there.



BTW: Do most boilers have their controls integrated on the boiler or
are they available as a remote unit? I wouldn't want to have to go in
the loft every time I need to change a setting.

Some have integrated timers although often that is optional anyway.

You would have the room thermostat or room thermostat and programmer
integrated in an appropriate room without TRV on the radiator.

Boilers may have control panels for system parameters and to report
faults. Usually these are used when setting up and not a lot after
that.

Those that have integrated controls should have a way to use an
external programmer. Check the installation manual for that.
Some more sophisticated boilers have provision for showing boiler
operation on a remote controller. You would then have a thermostat
on the cylinder to control its temperature.

If it helps, don't forget that there are wireless room programmers and
you can avoid wiring.

You would need to provision a gas supply - probably 22mm pipe - from
the meter or teeing from a 22mm pipe from the meter.

Also for a condensing boiler, there needs to be a way to get rid of
the condensate. This needs to be in plastic and commonly 22mm
overflow pipe is used for it. In a loft, a convenient way may be to
run it via a trap into the soil stack as long as the stack is plastic.
Otherwise it needs to be delivered to a suitable drain as the
condensate is mildly acidic.

..andy

To email, substitute .nospam with .gl

In article , W
wrote:
BTW: Do most boilers have their controls integrated on the
boiler or are they available as a remote unit? I wouldn't
want to have to go in the loft every time I need to change
a setting.

I've never heard of that but FWIW one of the things about the
Keston Celsius that is useful in our church installation is that
you can wire the run and fail signals to remote neons.

--
Tony Bryer SDA UK 'Software to build on' http://www.sda.co.uk
Free SEDBUK boiler database browser
http://www.sda.co.uk/qsedbuk.htm

"Andy Hall" wrote
....
| | = - cylinder of expanding foam
| Can you imagine what would happen if the box split or something
| else went wrong?. It would make Peter Parry's canoe story sound
| like a kids party.

Hmmm, expanding foam, kids' party, trick-or-treat coming up.

D'you think some set foam cut into a rectangle and coated with exlax would
pass as a crunchie bar in twilight?

Owain

In article ,
Tony Bryer writes:
In article , W
wrote:
BTW: Do most boilers have their controls integrated on the
boiler or are they available as a remote unit? I wouldn't
want to have to go in the loft every time I need to change
a setting.

It was an option for some of the boilers when I was looking
around.

I've never heard of that but FWIW one of the things about the
Keston Celsius that is useful in our church installation is that
you can wire the run and fail signals to remote neons.

I have it in mind to modify my Keston for remote operation
of the control panel. I have been breadboarding some ideas.
I've been using the "lockout" and "burner on" outputs since
it was installed.

--
Andrew Gabriel

On Tue, 28 Sep 2004 14:06:23 +0100, "Owain"
wrote:

"Andy Hall" wrote
...
| | = - cylinder of expanding foam
| Can you imagine what would happen if the box split or something
| else went wrong?. It would make Peter Parry's canoe story sound
| like a kids party.

Hmmm, expanding foam, kids' party, trick-or-treat coming up.

D'you think some set foam cut into a rectangle and coated with exlax would
pass as a crunchie bar in twilight?

Owain



Why make it complicated. Just give the herberts exlax chocolate and
done with it. The whole trick or treat thing is imported nonsense
anyway.

WHat happened to "penny for the guy"?

Carol singers belt out one line of "we wish you a merry christmas" and
ring the doorbell wanting money.

It's no good.


..andy

To email, substitute .nospam with .gl

"Andy Hall" wrote
| Why make it complicated. Just give the herberts exlax chocolate
| and done with it. The whole trick or treat thing is imported
| nonsense anyway.

They probably don't want chocolate anyway. Cigarettes for the juniors and
ecstacy for the secondary school neds.

| WHat happened to "penny for the guy"?

Inflation, Thatcherism, free enterprise.

| Carol singers belt out one line of "we wish you a merry christmas"
| and ring the doorbell wanting money.
| It's no good.

Never mind, I expect there'll be a nice sing-song to the record player down
the day centre. But I don't think I'll get a parcel from the Round Table
this year[1].

Owain

[1] I got two a few years ago; two of the intended recipients had, er,
demised in the interval between organisation and delivery.