My Boiler is on its last legs - had our annual service today and the British Gas Crook, sorry, Man said spare parts were no longer available etc etc

So I'm preparing for the worst. We currently have a vented(?) system - cold water tank in the loft and hot water cylinder in the Airing cupboard upstairs. Boiler itself is downstairs in the kitchen. We have an ensuite with a Shower cubicle - thermostatic shower valve fed by an Aqualisa pump from a hot and cold feed from cylinder/cold tank.
In the main bathroom, I have a power shower fed form the same hot and cold tanks.

Seems as if opinion is certainly skewed towards Combi systems - question (finally) is....will I need to replace my Showers (v v problematic) or can they run with a new combi system or similar. I'd plan to do as much DIY as poss - prep work and flushing etc etc - what do people think I should do?

Very grateful as ever

Alex

My Boiler is on its last legs - had our annual service today and the
British Gas Crook, sorry, Man said spare parts were no longer available
etc etc

Same old. Keep the old boiler until it starts going wrong. Unless it is
particularly old and inefficient, it is more environmentally friendly to
waste a little gas and save on a lot of manufacturing processes (with
horrible PCBs etc.).

Seems as if opinion is certainly skewed towards Combi systems -
question (finally) is....will I need to replace my Showers (v v
problematic) or can they run with a new combi system or similar.

If you're happy with the shower performance and don't mind the noise/space
of the pumped tanked system, keep them. There will be much less plumbing to
do and your system will almost certainly have superior bath filling
performance.

High flow rate combis suitable for multiple simultaneous showers are much
more expensive than the simple modulating system boiler you would need to
run your existing hot water system. Standard rate combis are well priced,
but aren't brilliant running two showers.

Christian.

"alexbartman" wrote in message
...

My Boiler is on its last legs - had our annual service today and the
British Gas Crook, sorry, Man said spare parts were no longer available
etc etc

So I'm preparing for the worst. We currently have a vented(?) system -
cold water tank in the loft and hot water cylinder in the Airing
cupboard upstairs. Boiler itself is downstairs in the kitchen. We
have an ensuite with a Shower cubicle - thermostatic shower valve fed
by an Aqualisa pump from a hot and cold feed from cylinder/cold tank.
In the main bathroom, I have a power shower fed form the same hot and
cold tanks.

Seems as if opinion is certainly skewed towards Combi systems -
question (finally) is....will I need to replace my Showers (v v
problematic) or can they run with a new combi system or similar. I'd
plan to do as much DIY as poss - prep work and flushing etc etc - what
do people think I should do?

Fit a high flow combi and remove the pump. Check with the mixer makers if
it is a high pressure model. Some can have the cartridge replaced from high
to low pressure.



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"Christian McArdle" wrote in message
et...
My Boiler is on its last legs - had our annual service today and the
British Gas Crook, sorry, Man said spare parts were no longer available
etc etc

Same old. Keep the old boiler until it starts going wrong. Unless it is
particularly old and inefficient, it is more environmentally friendly to
waste a little gas and save on a lot of manufacturing processes (with
horrible PCBs etc.).

Seems as if opinion is certainly skewed towards Combi systems -
question (finally) is....will I need to replace my Showers (v v
problematic) or can they run with a new combi system or similar.

If you're happy with the shower performance and don't mind the noise/space
of the pumped tanked system, keep them. There will be much less plumbing
to
do and your system will almost certainly have superior bath filling
performance.

High flow rate combis suitable for multiple simultaneous showers are much
more expensive than the simple modulating system boiler you would need to
run your existing hot water system. Standard rate combis are well priced,
but aren't brilliant running two showers.

Simple, use two combi's.



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In article ,
alexbartman wrote:
My Boiler is on its last legs - had our annual service today and the
British Gas Crook, sorry, Man said spare parts were no longer available
etc etc

Standard sales pitch. There's a very good chance the most needed spares
are still available - as it sounds like a basic boiler.

Of course if you *depend* on having a BG service contract there's nothing
you can do about these lies.

--
*Ah, I see the f**k-up fairy has visited us again

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

High flow rate combis suitable for multiple simultaneous showers are much
more expensive than the simple modulating system boiler you would need to
run your existing hot water system. Standard rate combis are well priced,
but aren't brilliant running two showers.

Simple, use two combi's.

Which, by definition, doubles the price.

Christian.

"Christian McArdle" wrote in message
. net...
High flow rate combis suitable for multiple simultaneous showers are
much
more expensive than the simple modulating system boiler you would need
to
run your existing hot water system. Standard rate combis are well
priced,
but aren't brilliant running two showers.

Simple, use two combi's.

Which, by definition, doubles the price.

Doubles the price of smaller low priced units. Two W-B Juniors can be had
for around £1,000 and will deliver approx 20 litres/min. Look around for a
20 l/min combi and see what the prices are.

But it gives you so much more and highly cost effective. One combi does one
shower, one the other, with one not robbing the other, combine the two for
the bath to give a high flow. One does upstairs heating and one does
downstairs heating, both with their own stat/programmers. Two totally
independent systems. You can have the rad temperatures low upstairs and high
downstairs as well. If one combi drops out there is always heat in the house
and hot water (great bonus). No large cylinder taking up space and making
the place look like a school boiler room, just small neat white boxes on the
wall saving space. One poster has already done this with great success.

The only disadvantage is that there are two service costs. With two boilers
side by side a deal can be struck to reduce this.



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Doubles the price of smaller low priced units. Two W-B Juniors can be had
for around £1,000 and will deliver approx 20 litres/min. Look around for
a
20 l/min combi and see what the prices are.

Or you could just keep the existing system and spend 500 quid on a single
boiler, forget all the combi nonsense (with attendent expensive/time
consuming replumbing) and have 80 litres/min.

Christian.

"Christian McArdle" wrote in message
. net...

Doubles the price of smaller low
priced units. Two W-B Juniors can be had
for around £1,000 and will deliver approx
20 litres/min. Look around for a
20 l/min combi and see what the prices are.

Or you could just keep the existing system and spend 500 quid on a single
boiler, forget all the combi nonsense (with attendent expensive/time
consuming replumbing) and have 80 litres/min.

£500 gets you from point A to point A. 80 l/min is overkill, and you will
only be getting that for a few minutes before the cylinder is exhausted.
Taken to extremes, the combi's will provide showers for as long as you want,
all day in there with two showers going if you are that way inclined. The
two combi's release valuable space and gives a natural simple zoned heating
system saving money on fuel bills. No contest, the two combi's win hands
down, on all points to gain zoned heating system providing two showers and
bath and liberating space: Two combis win on:

1. Low capital cost of installation
2. Running cost, upstairs heating can be off most of the day.
3. No waiting for showers
4. Showers don't run out of hot water
5. Simple zoned heating system with independent time zones.
6. Different rad temperatures on different floors.
7. Less controls to go wrong, with accompanying down time and expense. (no
zone valves and the likes)
8. Always heat and hot water. Two combi's means built-in redundancy.
9. Release valuable space for storage.

Only disadvantage is slightly more expensive on regular servicing, which is
overwhelmingly offset by the above points



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Two combis win on:

1. Low capital cost of installation

********. One boiler with no pipework changes will be less than half the
capital cost of two boilers with substantial changes to pipework.

2. Running cost, upstairs heating can be off most of the day.

Subzoning is easily achieved using a single boiler.

3. No waiting for showers

Have you ever used a storage system? There is no wait for showers.

4. Showers don't run out of hot water

A shower will not run out of hot water, provided the usage is below the
capacity of the coil. An old cylinder may have a poor coil, but would still
hold sufficient water for the longest of showers.

5. Simple zoned heating system with independent time zones.

Subzoning is easily achieved using a single boiler.

6. Different rad temperatures on different floors.

Which serves what purpose when you have TRVs and subzoned thermostatic
control?

7. Less controls to go wrong, with accompanying down time and expense.
(no
zone valves and the likes)

But multiple pumps and boilers, all of which can go wrong.

8. Always heat and hot water. Two combi's means built-in redundancy.

About the only advantage.

9. Release valuable space for storage.

Where are you putting the new boiler? The cylinder and tanks are often in
otherwise unused locations. You'll need to run a new gas line as well. The
existing 22mm won't be enough.

Only disadvantage is slightly more expensive on regular servicing, which
is
overwhelmingly offset by the above points

Which is why every house in the country has 2 combis. The case is so
compelling.

Christian.

In article ,
Doctor Evil wrote:
1. Low capital cost of installation

The cost of *installation* is lower with two boilers? Or just the capital
cost?

2. Running cost, upstairs heating can be off most of the day.

Little advantage given the way most use bedrooms for things other than
sleeping? Oh - and keep all doors closed at all times?

3. No waiting for showers

You don't have to with a storage system.

4. Showers don't run out of hot water

They wouldn't need to, given the time needed to get clean in those
dribbles.

5. Simple zoned heating system with independent time zones.

Not difficult to achieve with one system, but in practice of little use in
most ordinary homes.

6. Different rad temperatures on different floors.

Err, TRVs?

7. Less controls to go wrong, with accompanying down time and expense.
(no zone valves and the likes)

But two programmers, two programmable stats and most of all, two pumps?

8. Always heat and hot water. Two combi's means built-in redundancy.

And twice the chance of failure?

9. Release valuable space for storage.

Let me see - adding a second boiler releases space? Is this in a Tardis
sort of way?

Only disadvantage is slightly more expensive on regular servicing, which
is overwhelmingly offset by the above points

So you keep on saying. Most would consider it a lose lose situation.

With the extra installation costs well outweighing any savings against a
larger boiler.

--
*Why is it that rain drops but snow falls?

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

"Christian McArdle" wrote in message
. net...
Two combis win on:

1. Low capital cost of installation

********. One boiler with no pipework
changes will be less than half the
capital cost of two boilers with substantial
changes to pipework.

But the gains are terrific.

2. Running cost, upstairs heating can be off most of the day.

Subzoning is easily achieved using a single boiler.

It is NOT. You require zone valves, which take up space and the control
wiring and knowledge to do it to boot. Two combi's achieves this much
simpler with virtually no wiring worth talking about. To avoid Part P you
can even connect them up to a 3 pin socket.

3. No waiting for showers

Have you ever used a storage system? There is no wait for showers.

They run out though. No waiting for showers with a combi eiether. Ever used
one? And "two" high pressure showers can be running all day. Can't get
that with a storage system.

4. Showers don't run out of hot water

A shower will not run out of hot water,
provided the usage is below the
capacity of the coil.

Which means a large boiler and a new larger space consuming cylinder, in
this case. Getting expensive now. Two comb's is looking far more attractive.

5. Simple zoned heating system
with independent time zones.

Subzoning is easily achieved using a single boiler.

It is NOT. See above.

6. Different rad temperatures on different floors.

Which serves what purpose when
you have TRVs and subzoned thermostatic
control?

Economy and safer with kids about in the playroom with no exsessively hot
rads. The lower the boiler temp the more efficient. Turn upstairs to 61C
flow.

7. Less controls to go wrong, with
accompanying down time and expense.
(no zone valves and the likes)

But multiple pumps and boilers,
all of which can go wrong.

Two integrated pumps that do CH and DHW. As two boilers, the load is shared
and they both have an easier life. W-B Junior is simple with no 3-way valves

8. Always heat and hot water. Two combi's
means built-in redundancy.

About the only advantage.

You lack common reasoning.

9. Release valuable space for storage.

Where are you putting the new boiler?
The cylinder and tanks are often in
otherwise unused locations.

What sort of house do you have? Most British houses are far too small with
cylinder taking up valuable cupboard space.

You'll need to run a new gas line as well. The
existing 22mm won't be enough.

One for each. Not a great thing.

Only disadvantage is slightly more
expensive on regular servicing, which
is overwhelmingly offset by the above points

Which is why every house in the country
has 2 combis. The case is so compelling.

Most houses have a tank in the loft, a cylinder taking up cupboard space, a
shower you run around in to get wet, TWO taps on a basin so you are moving
your hands from one too hot tap to the other cold tap when washing them and
a boiler in the KITCHEN. Most other countries laugh at us. The British are
renowned for bad plumbing. Talk to an American who have been backpacking
around the UK. They can't wait to get home for a decent shower.

In the US many are going over to multi-points that output 200,000 plus
BTUs/hr. On-demand hot water is regarded as much superior to stored water.
Bosch, Takagi and Rinnai are the big players. Two combi's is roughly the
same output. The largest output multi-point in the world is a Takagi.

Read what I write and take it in, instead of thinking you know it all.



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"Christian McArdle" wrote:

If you're happy with the shower performance and don't mind the noise/space
of the pumped tanked system, keep them. There will be much less plumbing to
do and your system will almost certainly have superior bath filling
performance.

Superior bath filling performance - absolutely, why anyone would ever
want a combi escapes me, I can get up turn on the taps, have a ****,
clean my teeth and halfway through a shave the full size bath is
overflowing with steaming hot water. Wonderful. (and the tank still
has enough for the old woman to have her long shower)

Using a combi on a warm day in the middle of a once in 500 years
heatwave it would struggle to fill a 5 gallon bucket of bath
temperature water in a similar time (despite the manufacturers claims)

A few words for combi's

"cheap ****e from europe suitable for smelly frogs"
"the slowest way to run a bath - ever"
"the crappiest shower you ever had"
"a step back to the dark ages"

--

But the gains are terrific.

So you claim. However, claiming that capital costs are lower is simply
false. The capital costs are over double.

They run out though. No waiting for showers with a combi eiether. Ever
used
one?

Yes. You have to wait much longer, as you have to wait for the combi to fire
up and get up to speed, unless you have one with built in storage.

And "two" high pressure showers can be running all day. Can't get
that with a storage system.

Of course you can, if the boiler you choose has sufficient output (and the
cylinder has sufficient input) to cover the showers, then a storage system
would also not run out.

It is NOT. You require zone valves, which take up space and the control
wiring and knowledge to do it to boot.

It's hardly rocket science to wire up S-Plan systems. The wiring is
exceptionally simple.

It is NOT. See above.

It is extremely simple. If you're confused by wiring up a S-Plan system,
then you should have put down the tools long ago. It is only fractionally
more difficult that wiring up your iconic 2 combis.

In the US many are going over to multi-points that output 200,000 plus
BTUs/hr. On-demand hot water is regarded as much superior to stored water.
Bosch, Takagi and Rinnai are the big players. Two combi's is roughly the
same output. The largest output multi-point in the world is a Takagi.

Don't talk rot. They have crappy direct electric and gas heaters that have
the efficiency of a lit fart. They have very few instantaneous gas heaters
actually installed, although 24kW instantaneous electric heating is common
enough, with the obvious limitations thereof.

Christian.

With the extra installation costs well outweighing any savings against a
larger boiler.

Also, having two boilers means that your minimum modulation gets worse. In a
marginal heating situation, bumping along the bottom at 4-8kW, you want the
entire load on one boiler so it doesn't have to cycle unnecessarily. With 2
combis, you could have 2 boilers cycling instead of one pootling along at
minimum, at much greater efficiency.

Christian.

In article ,
Doctor Evil wrote:
Subzoning is easily achieved using a single boiler.

It is NOT. You require zone valves, which take up space

A zone valve takes up space? Do you live in a doll's house?

and the control wiring and knowledge to do it to boot.

Ah. Now the truth. You don't know how to wire them.

Two combi's achieves this much simpler with virtually no wiring worth
talking about. To avoid Part P you can even connect them up to a 3 pin
socket.

But double the CORGI fees for the gas work and commissioning?

Which planet are you on to-day?

--
*Ham and Eggs: Just a day's work for a chicken, but a lifetime commitment

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

"alexbartman" wrote in message
...

My Boiler is on its last legs - had our annual service today and the
British Gas Crook, sorry, Man said spare parts were no longer available
etc etc

So I'm preparing for the worst. We currently have a vented(?) system -
cold water tank in the loft and hot water cylinder in the Airing
cupboard upstairs. Boiler itself is downstairs in the kitchen. We
have an ensuite with a Shower cubicle - thermostatic shower valve fed
by an Aqualisa pump from a hot and cold feed from cylinder/cold tank.
In the main bathroom, I have a power shower fed form the same hot and
cold tanks.

Seems as if opinion is certainly skewed towards Combi systems -
question (finally) is....will I need to replace my Showers (v v
problematic) or can they run with a new combi system or similar. I'd
plan to do as much DIY as poss - prep work and flushing etc etc - what
do people think I should do?



What's the make & model and is there actually anything wrong with it to
warrant replacement or is it just BG "looking after their customers" by
suggesting replacement?



--
Richard Sampson

mail me at
richard at olifant d-ot co do-t uk

In article ,
Christian McArdle wrote:
With the extra installation costs well outweighing any savings against
a larger boiler.

Also, having two boilers means that your minimum modulation gets worse.
In a marginal heating situation, bumping along the bottom at 4-8kW, you
want the entire load on one boiler so it doesn't have to cycle
unnecessarily. With 2 combis, you could have 2 boilers cycling instead
of one pootling along at minimum, at much greater efficiency.

Good point. You'd have thought a 'pro' - who claims to have installed such
systems - to have known this. Perhaps some of his 'clients' might now sue
him?

--
*I started out with nothing, and I still have most of it.

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

"Christian McArdle" wrote in message
. net...
But the gains are terrific.

So you claim. However, claiming that
capital costs are lower is simply
false. The capital costs are over double.

For what you gain it is not. Putting a new boiler on an old systems adds
little value.

They run out though. No waiting for
showers with a combi eiether. Ever
used one?

Yes. You have to wait much longer,
as you have to wait for the combi to fire
up and get up to speed, unless you have
one with built in storage.

Are you having a laugh? You have to wait for the cold lag to empty in
adraw-off in a storage system.

And "two" high pressure showers can
be running all day. Can't get
that with a storage system.

Of course you can, if the boiler you choose
has sufficient output (and the
cylinder has sufficient input) to cover the
showers, then a storage system
would also not run out.

The boiler would have to be as big as the combined two combi's outputs, as
when the stored water depletes you will be running on boiler output.

It is NOT. You require zone valves,
which take up space and the control
wiring and knowledge to do it to boot.

It's hardly rocket science to wire up
S-Plan systems. The wiring is
exceptionally simple.

The wiring is NOT simple, especially to the uninitiated. The valves tale up
space and are another thing to go wrong which is expense.

It is NOT. See above.

It is extremely simple.

It ios NOT. see above.

In the US many are going over to
multi-points that output 200,000 plus
BTUs/hr. On-demand hot water is regarded
as much superior to stored water.
Bosch, Takagi and Rinnai are the big players.
Two combi's is roughly the same output.
The largest output multi-point in the world is a Takagi.

Don't talk rot.

You haven't a clue. You have been taking Andy Hall pills.

They have crappy direct electric
and gas heaters that have
the efficiency of a lit fart. They have
very few instantaneous gas heaters
actually installed, although 24kW
instantaneous electric heating is common
enough, with the obvious limitations thereof.

You still haven't a clue. Tankless on-demand (instantaneous, multi-point in
the UK), is increasing market share in the USA. Want 50 litres/min for 2
hours on end? Get a Takagi multi-point at 380,00 BTU/hr.



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"No Spam" wrote in message
...
"Christian McArdle" wrote:

If you're happy with the shower performance and don't mind the
noise/space
of the pumped tanked system, keep them. There will be much less plumbing
to
do and your system will almost certainly have superior bath filling
performance.

Superior bath filling performance - absolutely, why anyone would ever
want a combi escapes me, I can get up turn on the taps, have a ****,
clean my teeth and halfway through a shave the full size bath is
overflowing with steaming hot water. Wonderful. (and the tank still
has enough for the old woman to have her long shower)

Using a combi on a warm day in the middle of a once in 500 years
heatwave it would struggle to fill a 5 gallon bucket of bath
temperature water in a similar time (despite the manufacturers claims)

A few words for combi's

"cheap ****e from europe suitable for smelly frogs"
"the slowest way to run a bath - ever"
"the crappiest shower you ever had"
"a step back to the dark ages"

You obviously haven't a clue what you are on about. read this.....and read
it properly...

Here is a run down on combi's:

Firstly, a combi is a "combination" of the heating and water system in one
case, eliminating external tanks and cylinders, and generally supply hot
water at high main pressure. To confuse a little, some can run at very low
pressures and even off tanks. Generally most are fed from the mains. It is
generally a matter of mounting the boiler and connect up the pipes. The
expert designers have done the hard work for you and put all in one case.

Types of combi:

1) The Infinitely Continuous Combi -

Heats cold mains water instantly as it runs through the combi. It never runs
out of hot water. This is the most common type of combi, generally having
lower flowrates than Nos 2 & 3 below. The largest flow rate instant combi is
a two bathroom model, 22 litres/min ECO-Hometec. Being a condenser it is
very economical too. http://www.eco-hometec.co.uk

2) Unvented Cylinder Combi -

An unvented cylinder is a similar to a conventional cylinder but run off the
high-pressure cold mains. A combi with an integral unvented cylinder has
approx 60 litre cylinder heated to approx 80C, with a quick recovery coil
that takes all the boilers output. A fast acting cylinder thermostat ensures
the boiler pumps heat into the cylinder ASAP with a recovery rate from cold
around 5-8 mins (Ariston claim 8 mins). The 80C water is blended down to
about 45-50C. e.g's, Ariston Genus 27 Plus, Glow Worm, Powermax, Alpha
CD50.

3) Infinately Continuous/Unvented cylinder combi -

An example being the Alpha CD50, a combination of both having a two stage
flowrate, of high flowrate when using the stored water with an automatic
flow regulator switching in to reduce flow to an infinately continuous
flowrate of approx 13-14 litres/min.
http://www.alpha-boilers.com/products/CD50.html

4) Heat Bank Combi -

Incoming water is instantly heated running through a plate heat exchanger
(as is most instantaneous combi's) that takes its heat from a "domestic hot
water only" store of water at approx 80C (instantaneous combi's take the
heat from a heat-exchanger heater via the burner). A fast acting thermostat
ensures the boiler pumps all of its heat into the store ASAP with a recovery
rate about 5-8 mins from cold. The 80C water is blended down to about
45-50C. They are generally two stage flow rates, in that when the thermal
store is exhausted it reverts to what the burner can produce, which is
approx 11-12 litre/minute. e.g. Vokera & Worcester floor standing models
(standard washing machine sizes).

N.B. The heat bank is a variation of a thermal store, but is "not" a thermal
store in the conventional sense in that a coil carrying cold mains water
runs though a store of hot water kept at about 80C. Heat-banks are far more
efficient and give higher flowrates than conventional coiled thermal stores.
The stainless steel plate heat-exchangers do not scale up so easily.

5) Combined Primary Storage Unit

(Not classed as a combi, but a derivative of a combi, but still a one box
solution, so still in the same family)

These are a combination of a large thermal store, or heat bank, and boiler
in one casing. The units are large (larger than standard washing machine
size) and floor mounted. The heating is taken off the thermal store, which
in many cases the DHW taken off the store using a plate heat-exchanger
(heat-bank). Unlike the Heat-bank in 3) above the thermal store supplies
heating "and" DHW, giving the "combined" to the title. They are available
from 1 to 2.5 bathroom models. Gledhill do an excellent condensing
version, the Gulfsream 2000. http://www.gledhill.net

Nos. 2), 3), 4) & 5) have high flowrates. No. 1 "generally" has low
flowrates but there are always exceptions and some can be high - e.g. the
ECO-Hometec infinitely continuous combi, actually has a very high flowrate.
Nos 2), 3), 4) & 5) use stored water, but in different ways. Unlike No. 1
"some" versions will eventually run cold, but that takes quite a time, hence
some are referred to as "two bathroom" models, having the ability to fill
two baths with very fast recovery rates. As hot water is being drawn off
the high rating burner is also reheating. Very rare do these combi's run
out of hot water in average use. When taking one shower the burner may be
re-heating faster than what can be drawn-off. No. 3) above uses stored
water but will not run out of hot water (high and low flowrates). Most
versions of No. 4) above are two stage flowrate models (high and low
flowrates) and will also not run out of hot water.

There are combi models that give hot water and heating simultaneously as
Combined Primary Storage Units do. Most don't as they are hot water
priority.



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For what you gain it is not. Putting a new boiler on an old systems adds
little value.

You're now just arguing that the extra capital cost is justified. This is
very different from your original assertion that the capital cost was less.

Yes. You have to wait much longer,
as you have to wait for the combi to fire
up and get up to speed, unless you have
one with built in storage.

Are you having a laugh? You have to wait for the cold lag to empty in
adraw-off in a storage system.

Not only does a combi also have this cold lag (in addition to burner and
primary circuit lag), but the much reduced flow rate means that the cold lag
is of much greater time duration.

The wiring is NOT simple, especially to the uninitiated. The valves
tale up space and are another thing to go wrong which is expense.

If you can't wire up a zone valve, you are not a competent person to do any
electrics at all. It is less complicated than wiring a lighting point.

You still haven't a clue. Tankless on-demand (instantaneous, multi-point
in
the UK), is increasing market share in the USA.

Whilst there is no doubt that it is increasing market share, it does not
represent the installed base. I have no figures, but would guess that
instantaneous water heating of mains water is more common in the UK than the
US. It is not fair to compare the latest products in the US with UK products
that were installed 20 years ago.

Christian.

"Dave Plowman (News)" wrote in message
...
In article ,

....our resident loonie enter the fray.... Will be come out with something
sensible? we shall see......

With the extra installation costs well outweighing any savings against a
larger boiler.

No. He failed again.... sad but true....


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"Christian McArdle" wrote in message
. net...

Also, having two boilers means that your
minimum modulation gets worse. In a
marginal heating situation, bumping along
the bottom at 4-8kW,

Modern combi's have anti-cycle controls and also stat/programmers do too.
cycling will be minimal for each, and more than just having one boiler,.


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"Dave Plowman (News)" wrote in message
...

......He enters again...what will we expect this time... brace yourselves....

Good point.

....he says "good point", when it wasn;'t a good point. Well 0/10 for that
one.


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"Dave Plowman (News)" wrote in message
...

....illogical one is at it again....wee shall see.....

But double the CORGI fees for the gas work and commissioning?

...he tried but as wee all see couldn't make any sense at all...


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In article ,
Christian McArdle wrote:
Also, having two boilers means that your minimum modulation
gets worse. In a marginal heating situation, bumping along the
bottom at 4-8kW, you want the entire load on one boiler so it
doesn't have to cycle unnecessarily. With 2 combis, you could
have 2 boilers cycling instead of one pootling along at
minimum, at much greater efficiency.

Yes, but it's a simplicity v. efficiency v. redundancy equation.
At home I've got one combi, 2 heating zones controlled by
2xCM67's controlling 2MV's: maximum efficiency but no redundancy
and the extra failure point of the MV's. Two combis (or one combi
and a system boiler each feeding its own heating zone might lead
to increased cycling in mild weather but would reduce the risk of
being without heating and would, as IMM says, require much less
wiring. But I'm less than convinced that it really makes sense in
a normal home, though you might argue that the £50 for the
additional boiler service is a much cheaper form of insurance
than BG or a boiler maker's emergency service cover.

Our church heating, oft cited here, has two boilers and one
heating zone with a basic control system to try and ensure that
only one boiler runs when only one is needed. The upside is that
we always have some heating even if a boiler fails; the downside
is that four pumps are running instead of two. If there's some
problem with church heating it's a bit late to discover it at
1000 on a Sunday morning

Ultimately IMO there is no 'best': each option has its own
advantages and disadvantages.

--
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

"Christian McArdle" wrote in message
. net...

For what you gain it is not. Putting a
new boiler on an old systems adds
little value.

You're now just arguing that the extra capital
cost is justified. This is very different from your
original assertion that the capital cost was less.

If the boiler and cylinder need updating, there is no extra capital cost,
you also get two zones thrown in for free, and the on-demand water heating.

Yes. You have to wait much longer,
as you have to wait for the combi to fire
up and get up to speed, unless you have
one with built in storage.

Are you having a laugh? You have to
wait for the cold lag to empty in
adraw-off in a storage system.

Not only does a combi also have this
cold lag (in addition to burner and
primary circuit lag), but the much
reduced flow rate means that the cold lag
is of much greater time duration.

If it is, and some don't, it is not worthy of consideration.

If you can't wire up a zone valve,
you are not a competent person to do any
electrics at all. It is less complicated than
wiring a lighting point.

Total crap. A combi requires one flex connected to two terminals and a
mains cable. THAT IS IT!!!!!!! That is totally DIYable and a no brainer.
You can connect up the combi to a 3 pin plug and Part P has nor been
violated.

You still haven't a clue. Tankless on-demand
(instantaneous, multi-point in the UK), is
increasing market share in the USA.

Whilst there is no doubt that it is increasing
market share, it does not represent the
installed base. I have no figures, but would
guess that instantaneous water heating of
mains water is more common in the UK than the
US. It is not fair to compare the latest products
in the US with UK products
that were installed 20 years ago.

The US has only recently discovered instantaneous water heating. It is
increasing in sales. It is regarded as more eco and less to run. In some
parts of the US gas is more expensive than electricity. In the UK gas is
about 1/4 of electricity per kW. In the US, the differential varies a lot.



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"Tony Bryer" wrote in message
...
In article ,
Christian McArdle wrote:

Also, having two boilers means
that your minimum modulation
gets worse.

Yes, but it's a simplicity v. efficiency v.
redundancy equation. At home I've got
one combi, 2 heating zones controlled by
2xCM67's controlling 2MV's: maximum
efficiency but no redundancy and the
extra failure point of the MV's. Two combis
(or one combi and a system boiler each
feeding its own heating zone might lead
to increased cycling in mild weather but
would reduce the risk of being without
heating and would, as IMM says, require
much less wiring.

Hardly any at all. Only a stat wire.

But I'm less than convinced that it
really makes sense in a normal home,

Read my post on advantages. Clear, very clear.

though you might argue that the £50 for the
additional boiler service is a much cheaper
form of insurance than BG or a boiler maker's
emergency service cover.

That is true.

Ultimately IMO there is no 'best': each
option has its own advantages and
disadvantages.

Some have more advantages than other. In an average home, can be a very
large home, with 2 showers and one bath, a two combi setup is hard to argue
against, as all logic dictates for it. And as you have pointed out with the
insurance of an extra boiler keeping BG from ripping you off. It is also
highly cost effective, sinple and reliable, which escapes many here. As you
see here the detractors come up with twiddling piffling childish arguments.
Because they have never come across it before a mental block occurs. How
very British.

If a body jet shower is required then two combi's may not hack it, depending
on flowrate of course. If around 25 l/min for the shower then the two
combi's will do just do it with colds added of course, but no bath would be
run simultaneously, although if in the same bathroom as the shower the bath
would not be run anyway.

If larger flows are required then an integrated heat bank would be required,
probably again using two boilers, with each connected directly to the heat
bank. 58kW really does heat up fast, and when reheating, and using the heat
bank, the power of the two boilers and the energy in the stored water will
give a hell of a flow rate for quite a time. And of course the built-in
redundancy. Two 15/26 kW boilers is usually cheaper than one 190,000 BTU/hr
boiler, which gives no redundancy.











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In article ,
Doctor Evil wrote:
With the extra installation costs well outweighing any savings against
a larger boiler.

No. He failed again.... sad but true....

Ok then. I don't claim to be a pro. So I'm asking you to give some real
world total costs of installing two combis against one combi of comparable
output. Since you claim to have done this on many occasions, you should be
able to delve into your accounts and give actual examples.

--
*Forget about World Peace...Visualize using your turn signal.

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

In article ,
Doctor Evil wrote:
If you can't wire up a zone valve,
you are not a competent person to do any
electrics at all. It is less complicated than
wiring a lighting point.

Total crap. A combi requires one flex connected to two terminals and a
mains cable. THAT IS IT!!!!!!! That is totally DIYable and a no brainer.
You can connect up the combi to a 3 pin plug and Part P has nor been
violated.

So which are you? A heating engineer, as you've often claimed, or one of
the amateurs you so despise? I think we deserve to be told.

But I suspect you're a plumber. All that talk of flex...

--
*Time is the best teacher; unfortunately it kills all its students.

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

"Dave Plowman (News)" wrote in message
...
In article ,
Doctor Evil wrote:
If you can't wire up a zone valve,
you are not a competent person to do any
electrics at all. It is less complicated than
wiring a lighting point.

Total crap. A combi requires one flex connected to two terminals and a
mains cable. THAT IS IT!!!!!!! That is totally DIYable and a no
brainer.
You can connect up the combi to a 3 pin plug and Part P has nor been
violated.

....yes again he comes in with totaly inane off topic babble... just read...

So which are you? A heating engineer,
as you've often claimed, or one of
the amateurs you so despise? I think we
deserve to be told.

But I suspect you're a plumber. All that talk of flex...

......and that has a lot to do with wiring a combi? .. ...the men with the
white coats should be called in...




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"Dave Plowman (News)" wrote in message
...
In article ,
Doctor Evil wrote:

With the extra installation costs well
outweighing any savings against
a larger boiler.

No. He failed again.... sad but true....

.....after miserably failing he is coming back again.....I wonder why?

Ok then. I don't claim to be a pro. So I'm asking you to give some real
world total costs of installing two combis against one combi of comparable
output. Since you claim to have done this on many occasions, you should be
able to delve into your accounts and give actual examples.

Min Requirements:
two zones
2 showers
1 bath
Limited space in house.

W-B Junior £493 + 41 flue flue = £534
x 2 = £1,068. If you look around you get two boilers for less than this.
gives 20 l/min combined

W-B 440 Highflow £1098
gives 18 l.min Too low so, doesn't make it.
This is a stored water combi, so an infinitely continuous combi with 20
litres/min will be:

W-B Greenstar 40kW combi £1166
gives 16 l/min Too low so, doesn't make it.

To get 20 litres/min you need to go up to ECO-Hometec and spend about
£1,700 - £1,800

So, a saving of about £750 to start with. Then no zone valves, wiring
centre, etc to get two zones. More savings.

A two combi set up just needs 2 stat/programmers, what you would need with
any 2 zone setup.

Boiler W-B Greenstar £784
zone valves, wiring, cyl stats, wiring centre etc. approx £150 plus for good
makes.
unvented cylinder/heat bank, (£984 for 250 litre Megalflo)
extra piping and fittings, could be £200-300 (copper is at a world high)

Total £2218, which is over twice the price of two combi's. If you go to a
300 litre Megaflo to get some time in two simultaneous showers then even
more. As two combis will supply two showers all day and for ever, pumping
48 kW into DHW for ever. The cylinder cannot compete in performance here.
Then you have a large cylinder taking up valuable space

Then there is the advantages I have already highlighted:

1. Low capital cost of installation
2. Running cost, upstairs heating can be off most of the day.
3. No waiting for showers
4. Showers don't run out of hot water
5. Simple zoned heating system with independent time zones.
6. Different rad temperatures on different floors.
7. Less controls to go wrong, with accompanying down time and expense. (no
zone valves and the likes)
8. Always heat and hot water. Two combi's means built-in redundancy.
9. Release valuable space for storage.

Only disadvantage is slightly more expensive on regular servicing, which is
overwhelmingly offset by the above points

Now go away and think about it, hard I know, and don't back with caber
tossing silliness.



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Dave Plowman (News) wrote:
4. Showers don't run out of hot water
They wouldn't need to, given the time needed to get clean in those
dribbles.

Well, doh. You put two showers in the same enclosure. Then you can wash
both sides of you at once. Or if you have a bigger enclosure you can
have a two-person shower with separate temperature control for each person.

Owain

In article ,
Doctor Evil wrote:
But I suspect you're a plumber. All that talk of flex...

.....and that has a lot to do with wiring a combi? .. ...the men with
the white coats should be called in...

You've just proved your lack of any basic understanding of electrics. But
then, you'll not find the finer points easily on a website...

--
*Aim Low, Reach Your Goals, Avoid Disappointment *

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

In article ,
Doctor Evil wrote:
Ok then. I don't claim to be a pro. So I'm asking you to give some
real world total costs of installing two combis against one combi of
comparable output. Since you claim to have done this on many
occasions, you should be able to delve into your accounts and give
actual examples.

Snip the brochure prices.

Now go away and think about it, hard I know, and don't back with caber
tossing silliness.

I asked about real world installation costs - ie including labour. Yet
again you give an answer to the question you'd prefer to have read.

--
*Experience is something you don't get until just after you need it *

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

"Dave Plowman (News)" wrote in message
...
In article ,
Doctor Evil wrote:
Ok then. I don't claim to be a pro. So I'm asking you to give some
real world total costs of installing two combis against one combi of
comparable output. Since you claim to have done this on many
occasions, you should be able to delve into your accounts and give
actual examples.

......after cutting the caber, he is back.....

Snip the brochure prices.

....he is snipping now...

Now go away and think about it,
hard I know, and don't back with caber
tossing silliness.

Good advice from me above there....then he spoils it all by being distracted
by cabers.....

I asked about

....and he comes out with silliness, after me telling him not too. Would you
Adam & Eve it! Well I tried with our resident caber tosser, but to no
avail........ Sad but true.



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"Dave Plowman (News)" wrote in message
...
In article ,
Doctor Evil wrote:

...our redisnet cabnbver tosser says...yes he does....

But I suspect you're a plumber. All that talk of flex...

....I quite rightly replied.....

.....and that has a lot to do with wiring a combi? .. ...the men with
the white coats should be called in...

....and he continues with inane babble...

You've just proved your lack of

.....I know what you are all thinking, and sad it is to read too. Sad but
true.




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"Owain" wrote in message
. ..

...our resident caber tosser said.......silly I know...

Dave Plowman (News) wrote:
4. Showers don't run out of hot water
They wouldn't need to, given the time
| needed to get clean in those
dribbles.

...well some imaginative suggestions...

Well, doh. You put two showers in the
same enclosure. Then you can wash
both sides of you at once. Or if you have
a bigger enclosure you can
have a two-person shower with separate
temperature control for each person.

....fun too...


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In article ,
Owain wrote:
4. Showers don't run out of hot water
They wouldn't need to, given the time needed to get clean in those
dribbles.

Well, doh. You put two showers in the same enclosure. Then you can wash
both sides of you at once. Or if you have a bigger enclosure you can
have a two-person shower with separate temperature control for each
person.

:-)

On the one hand, it may be hot, and on the other hand, cold?

--
*Men are from Earth, women are from Earth. Deal with it.

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

In article , Dave Plowman (News)
writes

Which planet are you on to-day?

Dunno, but I think he must have stopped taking his medication.

--
..sigmonster on vacation