Discussion:
Condensing boilers
(too old to reply)
Timothy Murphy
2005-09-30 12:45:47 UTC
Permalink
I just had my central heating boiler serviced
by the gas company here,
for the first time in 14 years.

The service engineer said the boiler (Potterton "Profile Prima")
as in good nick, which surprised me.
But he mentioned that there are now "condensing boilers"
which save a bit of heat, as they extract heat from the fumes
which are expelled outside the house in older models.

Is it worth going over to such a model?
--
Timothy Murphy
e-mail (<80k only): tim /at/ birdsnest.maths.tcd.ie
tel: +353-86-2336090, +353-1-2842366
s-mail: School of Mathematics, Trinity College, Dublin 2, Ireland
tarquinlinbin
2005-09-30 12:52:33 UTC
Permalink
On Fri, 30 Sep 2005 13:45:47 +0100, Timothy Murphy
Post by Timothy Murphy
I just had my central heating boiler serviced
by the gas company here,
for the first time in 14 years.
The service engineer said the boiler (Potterton "Profile Prima")
as in good nick, which surprised me.
But he mentioned that there are now "condensing boilers"
which save a bit of heat, as they extract heat from the fumes
which are expelled outside the house in older models.
Is it worth going over to such a model?
it isnt worth upgrading your existing boiler unless you need to
becuase its in a bad way or your upgrading your kitchen and you want a
change etc etc. If your existing boiler is working fine then keep it
as you wont recoup the cost of the change in energy savings.

If you want to improve things,invest in insulation and other forms of
energy conservation (gas and electric!). You will only spend once on
insulation but you will spend all the time on heating a house which
leaks out heat like a colander.

joe



Remove antispam and add 670 after bra to email

Be a good Global citizen-CONSUME>CONFORM>OBEY

Circumcision- A crime and an abuse.
http://www.sexuallymutilatedchild.org/
Christian McArdle
2005-09-30 13:49:10 UTC
Permalink
Post by Timothy Murphy
The service engineer said the boiler (Potterton "Profile Prima")
as in good nick, which surprised me.
But he mentioned that there are now "condensing boilers"
which save a bit of heat, as they extract heat from the fumes
which are expelled outside the house in older models.
Generally speaking, it is neither economic nor environmentally friendly to
replace working models, unless they are particularly inefficient. The costs
(money and energy) of building a boiler are quite high and will take a long
time to offset against decreased fuel usage.

When the boiler does need replacing, you should replace with a condensing
model. Generally speaking, you are required to do so, but there are
exceptions, which you should not be tempted to use unless you really have
to.

Christian.
tarquinlinbin
2005-09-30 14:31:28 UTC
Permalink
On Fri, 30 Sep 2005 13:45:47 +0100, Timothy Murphy
Post by Timothy Murphy
I just had my central heating boiler serviced
by the gas company here,
for the first time in 14 years.
The service engineer said the boiler (Potterton "Profile Prima")
as in good nick, which surprised me.
But he mentioned that there are now "condensing boilers"
which save a bit of heat, as they extract heat from the fumes
which are expelled outside the house in older models.
Is it worth going over to such a model?
it isnt worth upgrading your existing boiler unless you need to
becuase its in a bad way or your upgrading your kitchen and you want a
change etc etc. If your existing boiler is working fine then keep it
as you wont recoup the cost of the change in energy savings.

If you want to improve things,invest in insulation and other forms of
energy conservation (gas and electric!). You will only spend once on
insulation but you will spend all the time on heating a house which
leaks out heat like a colander.

joe



Remove antispam and add 670 after bra to email

Be a good Global citizen-CONSUME>CONFORM>OBEY

Circumcision- A crime and an abuse.
http://www.sexuallymutilatedchild.org/
Doctor Drivel
2005-10-01 10:31:50 UTC
Permalink
Post by tarquinlinbin
On Fri, 30 Sep 2005 13:45:47 +0100, Timothy Murphy
Post by Timothy Murphy
I just had my central heating boiler serviced
by the gas company here,
for the first time in 14 years.
The service engineer said the boiler (Potterton "Profile Prima")
as in good nick, which surprised me.
But he mentioned that there are now "condensing boilers"
which save a bit of heat, as they extract heat from the fumes
which are expelled outside the house in older models.
Is it worth going over to such a model?
it isnt worth upgrading your existing boiler unless you need to
becuase its in a bad way or your upgrading your kitchen and you want a
change etc etc. If your existing boiler is working fine then keep it
as you wont recoup the cost of the change in energy savings.
Wrong. A condensing boiler can be had for under £500. That will save
around £100 per year (gas has just gone up 13%) So, 5 years "max" to
recoup the cost, lees if gas gone up again, and then massive saving over the
old boiler after the recoup period. Do some sums and stop arm waving.

http://www.uselessenergy.org.uk/boilers_prices.asp
Post by tarquinlinbin
If you want to improve things,invest in insulation and other forms of
energy conservation (gas and electric!). You will only spend once on
insulation but you will spend all the time on heating a house which
leaks out heat like a colander.
Good advice.
RedOnRed
2005-09-30 20:15:10 UTC
Permalink
Post by Timothy Murphy
I just had my central heating boiler serviced
by the gas company here,
for the first time in 14 years.
The service engineer said the boiler (Potterton "Profile Prima")
as in good nick, which surprised me.
But he mentioned that there are now "condensing boilers"
which save a bit of heat, as they extract heat from the fumes
which are expelled outside the house in older models.
Is it worth going over to such a model?
Yes it is worth going for such a model - if you have the money I would.

In fact I did a few months ago and am well pleased with the fuel savings,
quiet operation, quicker warm times and just generally pleased all round.
Oh, and I got a few eco warrior brownie points too.

Can't see what all the fuss is about. A nice new boiler for around £1500+. I
wish I'd done it ages ago.
Dave Plowman (News)
2005-09-30 23:20:22 UTC
Permalink
Post by RedOnRed
In fact I did a few months ago and am well pleased with the fuel
savings, quiet operation, quicker warm times and just generally pleased
all round.
There's no way a condensing boiler in principle will be quieter or have
faster warm up times than a non condenser.
--
*With her marriage she got a new name and a dress.*

Dave Plowman ***@davenoise.co.uk London SW
To e-mail, change noise into sound.
Doctor Drivel
2005-10-01 10:27:46 UTC
Permalink
Post by Dave Plowman (News)
Post by RedOnRed
In fact I did a few months ago and am well pleased with the fuel
savings, quiet operation, quicker warm times and just generally pleased
all round.
There's no way a condensing boiler in principle will be quieter or have
faster warm up times than a non condenser.
..more incoherrent babble based on no experience whatsoever. Culiflower
cheese today at the home is it?
Dave Plowman (News)
2005-10-01 11:13:40 UTC
Permalink
Post by Doctor Drivel
Post by Dave Plowman (News)
Post by RedOnRed
In fact I did a few months ago and am well pleased with the fuel
savings, quiet operation, quicker warm times and just generally
pleased all round.
There's no way a condensing boiler in principle will be quieter or have
faster warm up times than a non condenser.
..more incoherrent babble based on no experience whatsoever.
Please explain just how a condensing boiler is inherently quieter than a
non condenser. Similarly why it will warm up quicker. If you can manage to
before your lunchtime nap, or if still sober.
--
*Never miss a good chance to shut up *

Dave Plowman ***@davenoise.co.uk London SW
To e-mail, change noise into sound.
RedOnRed
2005-10-01 11:58:01 UTC
Permalink
Post by Dave Plowman (News)
Please explain just how a condensing boiler is inherently quieter than a
non condenser. Similarly why it will warm up quicker. If you can manage to
before your lunchtime nap, or if still sober.
I didn't say that a condensing boiler is technically quieter then a
non-condensing. My last boiler was 28 years old and suffered from bad,
noisey kettling. In that respect a new boiler is quieter.

My new boiler warms up quicker presumably due to it firing up on all
cylinders in its modulating mode, which a lot of old boilers may not have.
Additionally, due to our system being modified with the new boiler
installation, our boiler warms up the house quicker.
Dave Plowman (News)
2005-10-01 14:03:36 UTC
Permalink
Post by RedOnRed
Post by Dave Plowman (News)
Please explain just how a condensing boiler is inherently quieter than
a non condenser. Similarly why it will warm up quicker. If you can
manage to before your lunchtime nap, or if still sober.
I didn't say that a condensing boiler is technically quieter then a
non-condensing. My last boiler was 28 years old and suffered from bad,
noisey kettling. In that respect a new boiler is quieter.
Oh - I'm not disputing that. However, kettling isn't inherent in a non
condensing boiler - it's a fault.
Post by RedOnRed
My new boiler warms up quicker presumably due to it firing up on all
cylinders in its modulating mode, which a lot of old boilers may not have.
Modulating means *reducing* the heat output from maximum.
Post by RedOnRed
Additionally, due to our system being modified with the new
boiler installation, our boiler warms up the house quicker.
Well yes. But this has nothing to do with condensing or non condensing
boilers, that's all.
--
*Growing old is inevitable, growing up is optional *

Dave Plowman ***@davenoise.co.uk London SW
To e-mail, change noise into sound.
Doctor Drivel
2005-10-01 14:52:12 UTC
Permalink
Post by Dave Plowman (News)
Post by RedOnRed
Post by Dave Plowman (News)
Please explain just how a condensing boiler is inherently quieter than
a non condenser. Similarly why it will warm up quicker. If you can
manage to before your lunchtime nap, or if still sober.
I didn't say that a condensing boiler is technically quieter then a
non-condensing. My last boiler was 28 years old and suffered from bad,
noisey kettling. In that respect a new boiler is quieter.
Oh - I'm not disputing that. However, kettling isn't inherent in a non
condensing boiler - it's a fault.
More likely in cast iron boilers
Post by Dave Plowman (News)
Post by RedOnRed
My new boiler warms up quicker presumably due to it firing up on all
cylinders in its modulating mode, which a lot of old boilers may not have.
Modulating means *reducing* the heat output from maximum.
Post by RedOnRed
Additionally, due to our system being modified with the new
boiler installation, our boiler warms up the house quicker.
Well yes. But this has nothing to do with condensing or non condensing
boilers, that's all.
It is because it's not cast iron heats up faster.
Dave Plowman (News)
2005-10-01 16:14:41 UTC
Permalink
Post by Doctor Drivel
Post by Dave Plowman (News)
Post by RedOnRed
I didn't say that a condensing boiler is technically quieter then a
non-condensing. My last boiler was 28 years old and suffered from
bad, noisey kettling. In that respect a new boiler is quieter.
Oh - I'm not disputing that. However, kettling isn't inherent in a non
condensing boiler - it's a fault.
More likely in cast iron boilers
'Kettling' is the water in the heat exchanger boiling. It's a fault
condition and nothing to do with the type of heat exchanger material. Most
likely when the water circulation is cut off before or at the same time as
the burners. In other words, poor design of the system with no pump
over-run. Exactly the same would happen with any other construction of
heat exchanger.
Post by Doctor Drivel
Post by Dave Plowman (News)
Post by RedOnRed
My new boiler warms up quicker presumably due to it firing up on all
cylinders in its modulating mode, which a lot of old boilers may not have.
Modulating means *reducing* the heat output from maximum.
Post by RedOnRed
Additionally, due to our system being modified with the new boiler
installation, our boiler warms up the house quicker.
Well yes. But this has nothing to do with condensing or non condensing
boilers, that's all.
It is because it's not cast iron heats up faster.
So all non condensing boilers use cast iron heat exchangers? And no
condensing ones do?

Back to the catalogues, pet, and do some more reading.
--
* I like you. You remind me of when I was young and stupid

Dave Plowman ***@davenoise.co.uk London SW
To e-mail, change noise into sound.
Doctor Drivel
2005-10-01 17:30:53 UTC
Permalink
Post by Dave Plowman (News)
Post by Doctor Drivel
Post by Dave Plowman (News)
Post by RedOnRed
I didn't say that a condensing boiler is technically quieter then a
non-condensing. My last boiler was 28 years old and suffered from
bad, noisey kettling. In that respect a new boiler is quieter.
Oh - I'm not disputing that. However, kettling isn't inherent in a non
condensing boiler - it's a fault.
More likely in cast iron boilers
'Kettling' is the water in the heat exchanger boiling.
It is clear you know sweet nothing about boilers.

<snip drivel>
RedOnRed
2005-10-01 18:17:41 UTC
Permalink
Post by Dave Plowman (News)
Post by RedOnRed
Post by Dave Plowman (News)
Please explain just how a condensing boiler is inherently quieter than
a non condenser. Similarly why it will warm up quicker. If you can
manage to before your lunchtime nap, or if still sober.
I didn't say that a condensing boiler is technically quieter then a
non-condensing. My last boiler was 28 years old and suffered from bad,
noisey kettling. In that respect a new boiler is quieter.
Oh - I'm not disputing that. However, kettling isn't inherent in a non
condensing boiler - it's a fault.
I thought kettling was more to do with the age of the boiler, in so much
that they all fur up eventually and are then prone to kettling?
Post by Dave Plowman (News)
Post by RedOnRed
My new boiler warms up quicker presumably due to it firing up on all
cylinders in its modulating mode, which a lot of old boilers may not have.
Modulating means *reducing* the heat output from maximum.
I'm sure it does mean that. But doesn't it regulate the power too? If an old
boiler fires up only in 1st gear, a modulating boiler can use several
gears...thus increasing the heat output? Just an analogy.
Post by Dave Plowman (News)
Post by RedOnRed
Additionally, due to our system being modified with the new
boiler installation, our boiler warms up the house quicker.
Well yes. But this has nothing to do with condensing or non condensing
boilers, that's all.
--
*Growing old is inevitable, growing up is optional *
To e-mail, change noise into sound.
Dave Plowman (News)
2005-10-01 20:21:47 UTC
Permalink
Post by RedOnRed
Post by Dave Plowman (News)
Oh - I'm not disputing that. However, kettling isn't inherent in a non
condensing boiler - it's a fault.
I thought kettling was more to do with the age of the boiler, in so much
that they all fur up eventually and are then prone to kettling?
Assuming it's not a combi, there's no reason why it should fur up if
properly maintained.
Post by RedOnRed
Post by Dave Plowman (News)
Post by RedOnRed
My new boiler warms up quicker presumably due to it firing up on all
cylinders in its modulating mode, which a lot of old boilers may not have.
Modulating means *reducing* the heat output from maximum.
I'm sure it does mean that. But doesn't it regulate the power too? If an
old boiler fires up only in 1st gear, a modulating boiler can use
several gears...thus increasing the heat output? Just an analogy.
Older boilers fired up on maximum burner rate. They controlled the water
temperature by switching on and off. A modulating boiler can reducing the
flame size. So assuming the output and heat exchanger are the same, there
will be no difference in heat up time.
Post by RedOnRed
Post by Dave Plowman (News)
Post by RedOnRed
Additionally, due to our system being modified with the new
boiler installation, our boiler warms up the house quicker.
Well yes. But this has nothing to do with condensing or non condensing
boilers, that's all.
--
*Ah, I see the f**k-up fairy has visited us again

Dave Plowman ***@davenoise.co.uk London SW
To e-mail, change noise into sound.
RedOnRed
2005-10-01 22:22:17 UTC
Permalink
Post by Dave Plowman (News)
Older boilers fired up on maximum burner rate. They controlled the water
temperature by switching on and off. A modulating boiler can reducing the
flame size. So assuming the output and heat exchanger are the same, there
will be no difference in heat up time.
So what's the point of the modulating large and small flame?

Isn't it to control the rate of heat?

My old boiler wouldn't modulate and would heat on fixed flame which would be
lesser then a full on modulating one in my new boiler, which would surely
heat faster on full modulation?

A bigger flame means quicker heat doesn't it? Or is my sense of logic not
modulating right?
Andy Hall
2005-10-02 07:25:14 UTC
Permalink
Post by RedOnRed
Post by Dave Plowman (News)
Older boilers fired up on maximum burner rate. They controlled the water
temperature by switching on and off. A modulating boiler can reducing the
flame size. So assuming the output and heat exchanger are the same, there
will be no difference in heat up time.
So what's the point of the modulating large and small flame?
Isn't it to control the rate of heat?
My old boiler wouldn't modulate and would heat on fixed flame which would be
lesser then a full on modulating one in my new boiler, which would surely
heat faster on full modulation?
A bigger flame means quicker heat doesn't it? Or is my sense of logic not
modulating right?
The only reason that a newer boiler, be it condensing or not would
heat faster than an older generation one would be that the newer one
would typically have a stainless steel or aluminium heat exchanger and
the older one perhaps cast iron.

The point about modulating is three-fold:

- The boiler can run continuously rather than on/off for more of the
time. Cycling, especially with a cast iron model is less efficient,
especially with an old conventional or non-fan-assisted model where
excess heat at the end of the cycle ends up outside.

- A modulating boiler can begin to turn down the heat close to the
desired temperature for the house and reduce temperature overshoot.

- On a condensing boiler, operating at a lower temperature results in
more efficient operation.
--
.andy

To email, substitute .nospam with .gl
John
2005-10-02 13:35:10 UTC
Permalink
Post by Andy Hall
Post by RedOnRed
Post by Dave Plowman (News)
Older boilers fired up on maximum burner rate. They controlled the water
temperature by switching on and off. A modulating boiler can reducing the
flame size. So assuming the output and heat exchanger are the same, there
will be no difference in heat up time.
So what's the point of the modulating large and small flame?
Isn't it to control the rate of heat?
My old boiler wouldn't modulate and would heat on fixed flame which would be
lesser then a full on modulating one in my new boiler, which would surely
heat faster on full modulation?
A bigger flame means quicker heat doesn't it? Or is my sense of logic not
modulating right?
The only reason that a newer boiler, be it condensing or not would
heat faster than an older generation one would be that the newer one
would typically have a stainless steel or aluminium heat exchanger and
the older one perhaps cast iron.
- The boiler can run continuously rather than on/off for more of the
time. Cycling, especially with a cast iron model is less efficient,
especially with an old conventional or non-fan-assisted model where
excess heat at the end of the cycle ends up outside.
- A modulating boiler can begin to turn down the heat close to the
desired temperature for the house and reduce temperature overshoot.
- On a condensing boiler, operating at a lower temperature results in
more efficient operation.
No-one seems to have picked up on the rating of a replacement boiler. If the
old boiler was 60,000BTU/hr and ther new one is also 60,000BTU/hr then it
will modulate "down" from there and never up past it. Thus the rate of heat
up at maximum will only be the same as before. (Give or take a little bit
for a cleanbrand new heat exchanger)
RedOnRed
2005-10-02 13:59:16 UTC
Permalink
Post by John
No-one seems to have picked up on the rating of a replacement boiler. If
the old boiler was 60,000BTU/hr and ther new one is also 60,000BTU/hr then
it will modulate "down" from there and never up past it. Thus the rate of
heat up at maximum will only be the same as before. (Give or take a little
bit for a cleanbrand new heat exchanger)
In the mist of a shed load of confusing remarks on this debate, someone at
last makes sense.
Dave Plowman (News)
2005-10-02 21:36:02 UTC
Permalink
Post by John
No-one seems to have picked up on the rating of a replacement boiler. If
the old boiler was 60,000BTU/hr and ther new one is also 60,000BTU/hr
then it will modulate "down" from there and never up past it. Thus the
rate of heat up at maximum will only be the same as before. (Give or
take a little bit for a cleanbrand new heat exchanger)
Yup. Of course a modern boiler might well have a lower water capacity heat
exchanger and be made of a lower thermal mass body than a dino one. As I'd
expect. So like for like will heat up quicker. But that's got nothing to
do with whether it's a condenser or not.
--
*Why is the man who invests all your money called a broker? *

Dave Plowman ***@davenoise.co.uk London SW
To e-mail, change noise into sound.
John
2005-10-03 06:45:25 UTC
Permalink
Post by Dave Plowman (News)
Post by John
No-one seems to have picked up on the rating of a replacement boiler. If
the old boiler was 60,000BTU/hr and ther new one is also 60,000BTU/hr
then it will modulate "down" from there and never up past it. Thus the
rate of heat up at maximum will only be the same as before. (Give or
take a little bit for a cleanbrand new heat exchanger)
Yup. Of course a modern boiler might well have a lower water capacity heat
exchanger and be made of a lower thermal mass body than a dino one. As I'd
expect. So like for like will heat up quicker. But that's got nothing to
do with whether it's a condenser or not.
In terms of the total thermal mass of the heating system the variation to
mass contribution between high and low water content boilers will be three
quarters of sod-all. Whilst it exists, I think noticing the difference would
require very close study.
Of course there is nothing like the human mind for impressibility,
especially after spending lots of money<g>
Christian McArdle
2005-10-03 08:33:32 UTC
Permalink
Post by John
No-one seems to have picked up on the rating of a replacement boiler. If the
old boiler was 60,000BTU/hr and ther new one is also 60,000BTU/hr then it
will modulate "down" from there and never up past it. Thus the rate of heat
up at maximum will only be the same as before. (Give or take a little bit
for a cleanbrand new heat exchanger)
Except that the old non modulating boiler would have been sized to the house
to avoid excessive cycling (i.e. typically 10kW or 12kW ), whilst the new
modulating boiler needs no such treatment and will probably be a 28kW off
the shelf.

Modulating matters because you can (and do) install a much larger output
boiler.

Christian.
Doctor Drivel
2005-10-03 08:47:11 UTC
Permalink
Post by Christian McArdle
Post by John
No-one seems to have picked up on the rating of a replacement boiler. If
the
Post by John
old boiler was 60,000BTU/hr and ther new one is also 60,000BTU/hr then it
will modulate "down" from there and never up past it. Thus the rate of
heat
Post by John
up at maximum will only be the same as before. (Give or take a little bit
for a cleanbrand new heat exchanger)
Except that the old non modulating boiler would have been sized to the house
to avoid excessive cycling (i.e. typically 10kW or 12kW ), whilst the new
modulating boiler needs no such treatment and will probably be a 28kW off
the shelf.
Modulating matters because you can (and do) install a much larger output
boiler.
Which re-heats a quick recovery cylinder in no time, and a "very" fast warm
up of the CH too.
Tony Bryer
2005-10-03 10:00:08 UTC
Permalink
Post by Christian McArdle
Except that the old non modulating boiler would have been sized
to the house to avoid excessive cycling (i.e. typically 10kW or 12kW
),

It would have been sized to suit all but the coldest winter day, 18C
inside and -1 outside or whatever, whilst for half the heating season
the required heat is half this.
--
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
[Latest version QSEDBUK 1.10 released 4 April 2005]
Christian McArdle
2005-10-03 10:24:57 UTC
Permalink
Post by Tony Bryer
Post by Christian McArdle
Except that the old non modulating boiler would have been sized
to the house to avoid excessive cycling
It would have been sized to suit all but the coldest winter day, 18C
inside and -1 outside or whatever, whilst for half the heating season
the required heat is half this.
Indeed. However, they couldn't do what is common practice now and size to 3
times the maximum required, as this would have led to a grossly inefficient
system.

Chrtistian.
John
2005-10-03 12:18:35 UTC
Permalink
Post by Christian McArdle
Post by Tony Bryer
Post by Christian McArdle
Except that the old non modulating boiler would have been sized
to the house to avoid excessive cycling
It would have been sized to suit all but the coldest winter day, 18C
inside and -1 outside or whatever, whilst for half the heating season
the required heat is half this.
Indeed. However, they couldn't do what is common practice now and size to 3
times the maximum required, as this would have led to a grossly inefficient
system.
Whilst your assertation is correct the thread made no mention of increasing
the rating of the new boiler (and this may need a larger gas pipe).
Christian McArdle
2005-10-03 14:02:55 UTC
Permalink
Post by John
Whilst your assertation is correct the thread made no mention of increasing
the rating of the new boiler (and this may need a larger gas pipe).
Indeed. However I would guess that almost all condensing boiler
installations do considerably uprate the boiler power. So whilst it may be a
function of modern boiler's modulating capacity, rather than its condensing
nature, people replacing old boilers with condensing types are likely to see
much more rapid heating of the primary water circuit (and hence their
radiators).

Christian.
Ed Sirett
2005-10-03 20:05:01 UTC
Permalink
Post by Christian McArdle
Post by Tony Bryer
Post by Christian McArdle
Except that the old non modulating boiler would have been sized
to the house to avoid excessive cycling
It would have been sized to suit all but the coldest winter day, 18C
inside and -1 outside or whatever, whilst for half the heating season
the required heat is half this.
Indeed. However, they couldn't do what is common practice now and size to 3
times the maximum required, as this would have led to a grossly inefficient
system.
By the book in order for the system to comply with Part L of the BRs the
size of the boiler should be chosen to suit the property.
This means using a simplifed heat loss calculator and sizing the boiler
according to the results.

I argued (as I am wont to do) with the course tutor on the C&G 6083 course
(which central heating installers are now required to have). My assertion
was that the calculations are only _part_ of the choice for boiler sizing
and should be taken in to account with what is already installed and how
well or otherwise it was working, together with experience of what works.
The tutor (or rather the course syllabus) wanted us to always sart from
scratch.
--
Ed Sirett - Property maintainer and registered gas fitter.
The FAQ for uk.diy is at http://www.diyfaq.org.uk
Gas fitting FAQ http://www.makewrite.demon.co.uk/GasFitting.html
Sealed CH FAQ http://www.makewrite.demon.co.uk/SealedCH.html
Doctor Drivel
2005-10-01 13:25:11 UTC
Permalink
Post by Dave Plowman (News)
Post by Doctor Drivel
Post by Dave Plowman (News)
Post by RedOnRed
In fact I did a few months ago and am well pleased with the fuel
savings, quiet operation, quicker warm times and just generally
pleased all round.
There's no way a condensing boiler in principle will be quieter or have
faster warm up times than a non condenser.
..more incoherrent babble based on no experience whatsoever.
Please explain
It is not worth explaining to an old codger who can't understand. How was
the cauliflower cheese at the home?
Dave Plowman (News)
2005-10-01 14:06:18 UTC
Permalink
Post by Doctor Drivel
Post by Dave Plowman (News)
Post by Doctor Drivel
Post by Dave Plowman (News)
There's no way a condensing boiler in principle will be quieter or
have faster warm up times than a non condenser.
..more incoherrent babble based on no experience whatsoever.
Please explain
It is not worth explaining to an old codger who can't understand.
But then others might be interested in your explanation since this is a
newsgroup.

But of course the reason is simple. You don't know.
--
*Work like you don't need the money. Love like you've never been hurt.

Dave Plowman ***@davenoise.co.uk London SW
To e-mail, change noise into sound.
Doctor Drivel
2005-10-01 14:55:09 UTC
Permalink
Post by Doctor Drivel
Post by Dave Plowman (News)
Post by Doctor Drivel
Post by Dave Plowman (News)
There's no way a condensing boiler in principle will be quieter or
have faster warm up times than a non condenser.
..more incoherrent babble based on no experience whatsoever.
Please explain
It is not worth explaining to an old codger who can't understand.
But then ......
...it is not worth explaining to a senile old codger who can't understand.
Do you shovel coal into your boiler?
Dave Plowman (News)
2005-10-01 16:20:01 UTC
Permalink
Post by Doctor Drivel
Do you shovel coal into your boiler?
If I did, it would need servicing at least once a year. Is this how you
fuel yours and why you insist on yearly servicing?

And is this were you get your figures for '55%' efficiency?
--
*I got a sweater for Christmas. I really wanted a screamer or a moaner*

Dave Plowman ***@davenoise.co.uk London SW
To e-mail, change noise into sound.
Doctor Drivel
2005-10-01 17:25:18 UTC
Permalink
Post by Dave Plowman (News)
Post by Doctor Drivel
Do you shovel coal into your boiler?
If I did,
<snip drivel>
John Rumm
2005-10-01 13:55:43 UTC
Permalink
(sorry if this gets posted twice - newsfeed playing up)
Post by Timothy Murphy
But he mentioned that there are now "condensing boilers"
which save a bit of heat, as they extract heat from the fumes
which are expelled outside the house in older models.
Is it worth going over to such a model?
Depends on the circumstances. When you need to replace it for other
reasons then yes certainly, go for the best efficiency you can get all
other things being equal. Whether it is worthwhile scrapping a working
system requires some careful analysis. There is no point taking the
simplistic view of just comparing the raw cost of the boiler to the gas
savings, you need to look at the fuller picture.

Firstly how much are you spending on gas for your current boiler? The
model you list probably has an efficiency around about the 75% mark. So
going to a modern 90% model could reduce your gas bills by up to 15%.

What would it cost to have it changed - even a straight swap would
probably require some additional work for plumbing the condensate drain
etc. You may also need to spend some on upgrading controls to modern
build regs standards. Chances are even with a basic boiler you are
looking at £1500 unless you are up to doing the work yourself.

Modern high tech boilers are less likely to be happy going 14 years
without a service, so you need to factor in extra maintenance costs as
well.

To balance the costs you can also look at other factors: the modern
boiler will modulate over a decent range which combined with better
controls (TRVs on most of the rads etc) may give better temperature
regulation and comfort in your house. It may also take up less space and
be quieter / less ugly etc.

Environmentally the picture is less clear, since no manufactured product
is "environmentally friendly". These environmental costs of making your
new boiler and disposing of your old one are obviously hard to quantify
- but they are certainly not zero.
--
Cheers,

John.

/=================================================================\
| Internode Ltd - http://www.internode.co.uk |
|-----------------------------------------------------------------|
| John Rumm - john(at)internode(dot)co(dot)uk |
\=================================================================/
Doctor Drivel
2005-10-01 14:49:34 UTC
Permalink
Post by John Rumm
(sorry if this gets posted twice - newsfeed playing up)
Post by Timothy Murphy
But he mentioned that there are now "condensing boilers"
which save a bit of heat, as they extract heat from the fumes
which are expelled outside the house in older models.
Is it worth going over to such a model?
Depends on the circumstances. When you need to replace it for other
reasons then yes certainly, go for the best efficiency you can get all
other things being equal. Whether it is worthwhile scrapping a working
system requires some careful analysis. There is no point taking the
simplistic view of just comparing the raw cost of the boiler to the gas
savings, you need to look at the fuller picture.
Firstly how much are you spending on gas for your current boiler? The
model you list probably has an efficiency around about the 75% mark. So
going to a modern 90% model could reduce your gas bills by up to 15%.
What would it cost to have it changed - even a straight swap would
probably require some additional work for plumbing the condensate drain
etc. You may also need to spend some on upgrading controls to modern
build regs standards. Chances are even with a basic boiler you are
looking at £1500 unless you are up to doing the work yourself.
Modern high tech boilers are less likely to be happy going 14 years
without a service, so you need to factor in extra maintenance costs as
well.
My God! Nothing worse than amateur misadvise. All boiler have to be
serviced once a year. A one piece heat exchanger condensing boiler clean its
own heat exchanger.
informer
2005-10-02 06:51:19 UTC
Permalink
Post by Doctor Drivel
My God! Nothing worse than amateur misadvise. All boiler have to be
serviced once a year.
They might have to be but most aren't

I had my one serviced for the first time when it broke down after 14 years.
Doctor Drivel
2005-10-02 08:54:13 UTC
Permalink
Post by informer
Post by Doctor Drivel
My God! Nothing worse than amateur misadvise. All boiler have to be
serviced once a year.
They might have to be but most aren't
I had my one serviced for the first time when it broke down after 14 years.
You are totally irresponsible and should be prosecuted. The house is in
danger.
RedOnRed
2005-10-02 09:46:36 UTC
Permalink
Post by Timothy Murphy
Post by informer
Post by Doctor Drivel
My God! Nothing worse than amateur misadvise. All boiler have to be
serviced once a year.
They might have to be but most aren't
I had my one serviced for the first time when it broke down after 14
years.
You are totally irresponsible and should be prosecuted. The house is in
danger.
Time to get your fluffy handcuffs out you keep next to your bed for a
citizens arrest. But don't forget to take your gimp boy outfit off prior to
apprehension of this hardened recidivist.
raden
2005-10-02 17:39:06 UTC
Permalink
In message <dhoa9u$fa5$***@news.freedom2surf.net>, RedOnRed <***@abc.net>
writes
Post by RedOnRed
Post by Timothy Murphy
Post by informer
Post by Doctor Drivel
My God! Nothing worse than amateur misadvise. All boiler have to be
serviced once a year.
They might have to be but most aren't
I had my one serviced for the first time when it broke down after 14
years.
You are totally irresponsible and should be prosecuted. The house is in
danger.
Time to get your fluffy handcuffs out you keep next to your bed for a
citizens arrest. But don't forget to take your gimp boy outfit off prior to
apprehension of this hardened recidivist.
Look - dIMM's a waste of space and just a source of noise in uk.d-i-y

You know you're never going to get a sensible reply from him

Just don't reply to him
--
geoff
Doctor Drivel
2005-10-02 19:27:40 UTC
Permalink
Post by raden
writes
Post by RedOnRed
Post by Timothy Murphy
Post by informer
Post by Doctor Drivel
My God! Nothing worse than amateur misadvise. All boiler have to be
serviced once a year.
They might have to be but most aren't
I had my one serviced for the first time when it broke down after 14
years.
You are totally irresponsible and should be prosecuted. The house is in
danger.
Time to get your fluffy handcuffs out you keep next to your bed for a
citizens arrest. But don't forget to take your gimp boy outfit off prior to
apprehension of this hardened recidivist.
Look - dIMM's
Maxie!!! Are you about to jilt Dim Lin, the Oriental enchantress, the love
of your life? My, oh, my!
Dave Plowman (News)
2005-10-02 21:31:24 UTC
Permalink
Post by Doctor Drivel
Post by informer
I had my one serviced for the first time when it broke down after 14 years.
You are totally irresponsible and should be prosecuted. The house is in
danger.
Is that the same as flooding foundations through faulty jointing of
plastic pipes with a hacksaw rather than spending pennies on the correct
tool?

Think we should be told.

BTW, I must have asked a hundred times for your advice on servicing a
boiler, safety wise. With no reply.

Others will draw their own conclusions.
--
*Time is the best teacher; unfortunately it kills all its students.

Dave Plowman ***@davenoise.co.uk London SW
To e-mail, change noise into sound.
Doctor Drivel
2005-10-03 08:11:15 UTC
Permalink
Post by Dave Plowman (News)
Post by Doctor Drivel
Post by informer
I had my one serviced for the first time when it broke down after 14 years.
You are totally irresponsible and should be prosecuted. The house is in
danger.
Is that the same as flooding foundations
Flooding foundations has nothing to do with boiler services.

<snip senile drivel>
Dave Plowman (News)
2005-10-03 16:58:31 UTC
Permalink
Post by Doctor Drivel
Post by Dave Plowman (News)
Post by Doctor Drivel
You are totally irresponsible and should be prosecuted. The house
is in danger.
Is that the same as flooding foundations
Flooding foundations has nothing to do with boiler services.
When did being on topic ever concern you?
--
*Always borrow money from pessimists - they don't expect it back *

Dave Plowman ***@davenoise.co.uk London SW
To e-mail, change noise into sound.
Doctor Drivel
2005-10-03 19:00:07 UTC
Permalink
Post by Dave Plowman (News)
Post by Doctor Drivel
Post by Dave Plowman (News)
Post by Doctor Drivel
You are totally irresponsible and should be prosecuted. The house
is in danger.
Is that the same as flooding foundations
Flooding foundations has nothing to do with boiler services.
When did being on topic ever concern you?
It obviously doesn't concern you. His condition is past the point of no
return.
Dave Plowman (News)
2005-10-04 19:10:56 UTC
Permalink
Post by Doctor Drivel
Post by Dave Plowman (News)
Post by Doctor Drivel
Flooding foundations has nothing to do with boiler services.
When did being on topic ever concern you?
It obviously doesn't concern you. His condition is past the point of no
return.
Since the his obviously refers to the previous quote...
--
*Your kid may be an honours student, but you're still an idiot.

Dave Plowman ***@davenoise.co.uk London SW
To e-mail, change noise into sound.
Doctor Drivel
2005-10-04 20:04:31 UTC
Permalink
Post by Dave Plowman (News)
Post by Doctor Drivel
Post by Dave Plowman (News)
Post by Doctor Drivel
Flooding foundations has nothing to do with boiler services.
When did being on topic ever concern you?
It obviously doesn't concern you. His condition is past the point of no
return.
Since the
He is still confused. Poor soul.
Andy Champ
2005-10-02 20:37:01 UTC
Permalink
Post by Doctor Drivel
My God! Nothing worse than amateur misadvise. All boiler have to be
serviced once a year. A one piece heat exchanger condensing boiler clean its
own heat exchanger.
OK, sentence by sentence:

(1) No problem, I understand this one.

(2) misadvice? Advise is a verb, not a noun. But I;m not sure
misadvice is a word either!

(3) Boilers

(4) Enough of the pedantry, and the real point. What does that sentence
mean?

Andy
RedOnRed
2005-10-02 20:39:03 UTC
Permalink
Post by Andy Champ
Post by Doctor Drivel
My God! Nothing worse than amateur misadvise. All boiler have to be
serviced once a year. A one piece heat exchanger condensing boiler clean its
own heat exchanger.
(1) No problem, I understand this one.
(2) misadvice? Advise is a verb, not a noun. But I;m not sure misadvice
is a word either!
(3) Boilers
(4) Enough of the pedantry, and the real point. What does that sentence
mean?
Andy
Seems simple enough to understand to me, until you complicated it with
profound pedantism and your hilarious subtle brand of condescension - that
is.
Doctor Drivel
2005-10-03 08:12:08 UTC
Permalink
Post by Andy Champ
Post by Doctor Drivel
My God! Nothing worse than amateur misadvise. All boiler have to be
serviced once a year. A one piece heat exchanger condensing boiler clean its
own heat exchanger.
(1) No problem, I understand this one.
(2) misadvice? Advise is a verb, not a noun. But I;m not sure
misadvice is a word either!
(3) Boilers
(4) Enough of the pedantry, and the real point. What does that sentence
mean?
Are you foreign?
Andy Champ
2005-10-03 22:54:05 UTC
Permalink
<snipped to the relevant bits>
Post by Doctor Drivel
A one piece heat exchanger condensing boiler clean its own heat exchanger.
What does that sentence mean?
Are you foreign?
From some points of view, yes.

However, I'm honestly puzzled.

I thought most condensers were multi-part heat exchangers. However I
can't see how the number of parts used to manufacture the heat
exchanger, nor whether or not it has water on the outside, can have any
relevance to cleanliness.

Andy
Doctor Drivel
2005-10-03 22:02:59 UTC
Permalink
Post by Andy Champ
However, I'm honestly puzzled.
I thought most condensers were multi-part heat exchangers.
Nope, only naff ones.
Post by Andy Champ
However I
can't see how the number of parts
used to manufacture the heat
exchanger, nor whether or not it has water
on the outside, can have any
relevance to cleanliness.
A one piece heat exchanger with a top mounted burner and flue from the
bottom, will clean itself inside with condensate washing down the walls.
Dave Plowman (News)
2005-10-04 19:13:07 UTC
Permalink
Post by Doctor Drivel
A one piece heat exchanger with a top mounted burner and flue from the
bottom, will clean itself inside with condensate washing down the walls.
So needs less servicing than an older boiler?
--
*Black holes are where God divided by zero *

Dave Plowman ***@davenoise.co.uk London SW
To e-mail, change noise into sound.
Doctor Drivel
2005-10-04 20:05:33 UTC
Permalink
Post by Dave Plowman (News)
Post by Doctor Drivel
A one piece heat exchanger with a top mounted burner and flue from the
bottom, will clean itself inside with condensate washing down the walls.
So needs less servicing than an older boiler?
An annual service of less intensity. Also running more efficiently for
longer.
Andy Champ
2005-10-04 20:40:59 UTC
Permalink
Post by Doctor Drivel
A one piece heat exchanger with a top mounted burner and flue from the
bottom, will clean itself inside with condensate washing down the walls.
I'm surprised there's that much coming out. Still, I suppose it *is* a
weak acid, which must help a bit.

Ta

Andy
Dave Fawthrop
2005-10-01 14:03:49 UTC
Permalink
On Fri, 30 Sep 2005 13:45:47 +0100, Timothy Murphy
<***@birdsnest.maths.tcd.ie> wrote:

| I just had my central heating boiler serviced
| by the gas company here,
| for the first time in 14 years.
|
| The service engineer said the boiler (Potterton "Profile Prima")
| as in good nick, which surprised me.
| But he mentioned that there are now "condensing boilers"
| which save a bit of heat, as they extract heat from the fumes
| which are expelled outside the house in older models.
|
| Is it worth going over to such a model?

It is well worth doing the sums to see how much you would save.
On our *very* well insulated extended semi, we spent only GBP 370 in 2004
on heating plus Domestic Hot Water, of which about GBP 150.

So if efficiency of a 25 year old boiler was about 70%, a high efficiency
one 80% (sedbuk) and a condensing boiler 90% (sedbuk) we could only save
GBP 37 per year going to a High Efficiency one and GBP 75 for a condensing
one. These give payback times of 5 to 20 years depending on how much one
allows for installation costs. In pure economic terms I would expect a
payback of more than 10 years, and preferably over 20 years, the expected
life of a boiler.

In our case, the change would not be cost effective. However, because the
boiler was clapped out and as part of a remodeling of the kitchen it will
go ahead, probably a condensing one, because it would be greener.

I would strongly suggest that you do some cost and savings estimates with
your own figures, allowing a reasonable inflation factor for gas costs,
before replacing a boiler which is in "good nick".
--
Dave Fawthrop <dave hyphenologist co uk>
The London suicide bombers killed innocent commuters.
Animal rights terrorists and activists kill innocent patients.
Doctor Drivel
2005-10-01 14:53:51 UTC
Permalink
Post by tarquinlinbin
On Fri, 30 Sep 2005 13:45:47 +0100, Timothy Murphy
| I just had my central heating boiler serviced
| by the gas company here,
| for the first time in 14 years.
|
| The service engineer said the boiler (Potterton "Profile Prima")
| as in good nick, which surprised me.
| But he mentioned that there are now "condensing boilers"
| which save a bit of heat, as they extract heat from the fumes
| which are expelled outside the house in older models.
|
| Is it worth going over to such a model?
It is well worth doing the sums to see how much you would save.
On our *very* well insulated extended semi, we spent only GBP 370 in 2004
on heating plus Domestic Hot Water, of which about GBP 150.
So if efficiency of a 25 year old boiler was about 70%,
More like 55%.
Dave Plowman (News)
2005-10-01 16:17:57 UTC
Permalink
Post by Doctor Drivel
Post by Dave Fawthrop
So if efficiency of a 25 year old boiler was about 70%,
More like 55%.
More numbers plucked out of the air.

If it were 55% and your modern boiler was 108% or whatever it would near
half the gas consumption. And not even the wildest of advertising claims
that.
--
*I'm really easy to get along with once people learn to worship me

Dave Plowman ***@davenoise.co.uk London SW
To e-mail, change noise into sound.
Doctor Drivel
2005-10-01 17:26:07 UTC
Permalink
Post by Dave Plowman (News)
Post by Doctor Drivel
Post by Dave Fawthrop
So if efficiency of a 25 year old boiler was about 70%,
More like 55%.
More numbers
Yes 55 is a number.

<snip senile drivel>
RedOnRed
2005-10-01 18:14:13 UTC
Permalink
Post by Dave Fawthrop
So if efficiency of a 25 year old boiler was about 70%, a high efficiency
Before you embark on a load of misleading figures. The efficiency of a 25
year old boiler is likely to be around 55% efficient. Like the one I just
got shot of.
Dave Plowman (News)
2005-10-01 20:14:17 UTC
Permalink
Post by RedOnRed
Before you embark on a load of misleading figures. The efficiency of a
25 year old boiler is likely to be around 55% efficient. Like the one I
just got shot of.
It really depends on the type of 25 year old boiler. In 1980 there were
plenty that bettered that and by quite some margin.
--
*I'm pretty sure that sex is better than logic, but I can't prove it.

Dave Plowman ***@davenoise.co.uk London SW
To e-mail, change noise into sound.
Capitol
2005-10-02 19:38:35 UTC
Permalink
Post by RedOnRed
Before you embark on a load of misleading figures. The efficiency of a 25
year old boiler is likely to be around 55% efficient. Like the one I just
got shot of.
1973, Ideal Standard efficiency, 76%

Regards
Capitol
John Rumm
2005-10-02 20:03:17 UTC
Permalink
Post by Capitol
Post by RedOnRed
Before you embark on a load of misleading figures. The efficiency of a
25 year old boiler is likely to be around 55% efficient. Like the one
I just got shot of.
1973, Ideal Standard efficiency, 76%
If you wander through the SEDBUK database, there are very few that are
as low as 55% (39 models out of over 3,300 listed - mostly poxytons).

There are a few hundred at 65%, but the vast bulk are 70% or better.
--
Cheers,

John.

/=================================================================\
| Internode Ltd - http://www.internode.co.uk |
|-----------------------------------------------------------------|
| John Rumm - john(at)internode(dot)co(dot)uk |
\=================================================================/
RedOnRed
2005-10-02 21:01:22 UTC
Permalink
Post by Capitol
Post by RedOnRed
Before you embark on a load of misleading figures. The efficiency of a 25
year old boiler is likely to be around 55% efficient. Like the one I just
got shot of.
1973, Ideal Standard efficiency, 76%
Regards
Capitol
That's odd, my 1977 Ideal Standard floor stander was 55%.

76% for a 1973 model sounds a remarkable feat of engineering.

In 1973 with big flares, collars and lapels...wastage was a way of life.
Capitol
2005-10-02 21:15:23 UTC
Permalink
Post by RedOnRed
Post by Capitol
Post by RedOnRed
Before you embark on a load of misleading figures. The efficiency of a 25
year old boiler is likely to be around 55% efficient. Like the one I just
got shot of.
1973, Ideal Standard efficiency, 76%
Regards
Capitol
That's odd, my 1977 Ideal Standard floor stander was 55%.
76% for a 1973 model sounds a remarkable feat of engineering.
In 1973 with big flares, collars and lapels...wastage was a way of life.
Input, 24.3KW
Output, 18.5KW
To water, 17.6KW
To local ambient, 0.9KW

Or, another model

Input, 123KW
Output, 96KW
To water, 28.3KW
To local ambient, 1.8KW
Efficiency, 78%


Regards
Capitol
Andy Hall
2005-10-02 22:06:54 UTC
Permalink
On Sun, 02 Oct 2005 22:15:23 +0100, Capitol
Post by Capitol
Post by RedOnRed
Post by Capitol
Post by RedOnRed
Before you embark on a load of misleading figures. The efficiency of a 25
year old boiler is likely to be around 55% efficient. Like the one I just
got shot of.
1973, Ideal Standard efficiency, 76%
Regards
Capitol
That's odd, my 1977 Ideal Standard floor stander was 55%.
76% for a 1973 model sounds a remarkable feat of engineering.
In 1973 with big flares, collars and lapels...wastage was a way of life.
Input, 24.3KW
Output, 18.5KW
To water, 17.6KW
To local ambient, 0.9KW
Or, another model
Input, 123KW
Output, 96KW
To water, 28.3KW
To local ambient, 1.8KW
Efficiency, 78%
Regards
Capitol
Except that these are raw, optimum figures, not seasonally adjusted as
are used today.
--
.andy

To email, substitute .nospam with .gl
Dave Plowman (News)
2005-10-03 16:57:30 UTC
Permalink
Post by Andy Hall
Except that these are raw, optimum figures, not seasonally adjusted as
are used today.
Trouble is that the seasonally adjusted ones are all very well, but don't
tell the true story as regards running costs. Most would expect a 100%
efficient boiler to use exactly half the amount of gas of a 50% one. But
once you introduce fiddle factors like seasonal adjustment things become
murky for the average punter trying to work out whether replacement of an
otherwise serviceable boiler is economic - and that's before the high
failure rate of expensive electronic components necessary for high
efficiency boilers is factored in.
--
*Welcome to Shit Creek - sorry, we're out of paddles*

Dave Plowman ***@davenoise.co.uk London SW
To e-mail, change noise into sound.
Andy Hall
2005-10-03 21:17:53 UTC
Permalink
On Mon, 03 Oct 2005 17:57:30 +0100, "Dave Plowman (News)"
Post by Dave Plowman (News)
Post by Andy Hall
Except that these are raw, optimum figures, not seasonally adjusted as
are used today.
Trouble is that the seasonally adjusted ones are all very well, but don't
tell the true story as regards running costs. Most would expect a 100%
efficient boiler to use exactly half the amount of gas of a 50% one. But
once you introduce fiddle factors like seasonal adjustment things become
murky for the average punter trying to work out whether replacement of an
otherwise serviceable boiler is economic - and that's before the high
failure rate of expensive electronic components necessary for high
efficiency boilers is factored in.
There is a defined SEDBUK procedure which will give a better picture
but not completely accurate one for a given scenario. However, it is
the same, so that for comparison purposes between products of similar
spec. is reasonable.

Reliability is a matter of engineering design and component and
manufacturing quality. If you pay little, don't be surprised to get
crap. If you pay a lot and don't get good quality, apply boot to
supplier's backside.
--
.andy

To email, substitute .nospam with .gl
Dave Plowman (News)
2005-10-04 19:19:34 UTC
Permalink
Post by Dave Plowman (News)
Trouble is that the seasonally adjusted ones are all very well, but
don't tell the true story as regards running costs. Most would expect a
100% efficient boiler to use exactly half the amount of gas of a 50%
one. But once you introduce fiddle factors like seasonal adjustment
things become murky for the average punter trying to work out whether
replacement of an otherwise serviceable boiler is economic - and that's
before the high failure rate of expensive electronic components
necessary for high efficiency boilers is factored in.
There is a defined SEDBUK procedure which will give a better picture but
not completely accurate one for a given scenario. However, it is the
same, so that for comparison purposes between products of similar spec.
is reasonable.
I'd agree with that, but simpletons like Drivel use efficiency figures to
'quote' actual gas bill reductions when replacing older boilers.
Reliability is a matter of engineering design and component and
manufacturing quality. If you pay little, don't be surprised to get
crap. If you pay a lot and don't get good quality, apply boot to
supplier's backside.
But there's far more to go wrong in an electronically controlled boiler.
To me it would make sense if the electronics were mounted some way away
from the boiler so they could be kept at a near constant temperature.
--
*Virtual reality is its own reward*

Dave Plowman ***@davenoise.co.uk London SW
To e-mail, change noise into sound.
Doctor Drivel
2005-10-04 20:09:14 UTC
Permalink
Post by Dave Plowman (News)
Post by Dave Plowman (News)
Trouble is that the seasonally adjusted ones are all very well, but
don't tell the true story as regards running costs. Most would expect a
100% efficient boiler to use exactly half the amount of gas of a 50%
one. But once you introduce fiddle factors like seasonal adjustment
things become murky for the average punter trying to work out whether
replacement of an otherwise serviceable boiler is economic - and that's
before the high failure rate of expensive electronic components
necessary for high efficiency boilers is factored in.
There is a defined SEDBUK procedure which will give a better picture but
not completely accurate one for a given scenario. However, it is the
same, so that for comparison purposes between products of similar spec.
is reasonable.
I'd agree with that,
..here is a man who doesn't know, a man who has no clue
..about the things which are known to folks like me and you

..vacant in his head
..no knoweldge, reason, logic, this must be said

..drivel and babble just comes so
..relentless, incoherrent in it flow

..it's time take no notice of this senile babbling fool
..just thank the Lord you are sane, normal and cool

Tony Bryer
2005-10-02 22:06:57 UTC
Permalink
Post by Capitol
Input, 24.3KW
Output, 18.5KW
To water, 17.6KW
To local ambient, 0.9KW
Or, another model
Input, 123KW
Output, 96KW
To water, 28.3KW
To local ambient, 1.8KW
Efficiency, 78%
Those sound like bench efficiencies running at full load. The SEDBUK
efficiency formulae take account of the boiler running at 30% load
which for an old non-modulating CI boiler will result in it only
firing intermittently. When it switches off loads of heat stored in
the heat exchanger vanishes up the flue, and when it comes back on all
that CI has to be brought back up to temperature.
--
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
[Latest version QSEDBUK 1.10 released 4 April 2005]
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