I have a 20 years old Glow-worm Spacesaver wall boiler which works fine,
providing pumped CH and gravity DHW.
B/Gas 3 star engineers keep telling me the they can "no longer guarantee to
be able to source spares"...ie a sales ploy to sell a new boiler.
Our local council are supplying discounted high efficiency boilers as a
greening initiative, but I reckon the bill will be £2k with fitting and
maybe mods to the exisiting system.
Any of you experts got any impartial advice ?
My gut instinct is to try and source spares for my existing boiler to keep
it going as long as possible.
What do you think.?

My gut instinct is to try and source spares for my existing boiler to keep
it going as long as possible.

What do you think.?

Keep it going. Start putting money into a replacement fund for when it
finally breaks down terminally. Don't bother with boiler insurance. If you
hadn't paid for it and just put the cash into a bank account, you'd probably
already have saved enough for a new boiler...

Christian.

In an earlier contribution to this discussion,
Roger wrote:

I have a 20 years old Glow-worm Spacesaver wall boiler which works
fine, providing pumped CH and gravity DHW.
B/Gas 3 star engineers keep telling me the they can "no longer
guarantee to be able to source spares"...ie a sales ploy to sell a
new boiler.
Our local council are supplying discounted high efficiency boilers as
a greening initiative, but I reckon the bill will be £2k with fitting
and maybe mods to the exisiting system.
Any of you experts got any impartial advice ?
My gut instinct is to try and source spares for my existing boiler to
keep it going as long as possible.
What do you think.?

I would update the system at a time of *my* choosing, and certainly *not*
employ BG to do it.

It's pretty certainly a sales ploy to try to sell you a new boiler -
although there *may* be a risk of not being able to get spares at some
point, which would leave your stranded. Meanwhile BG still seem willing to
take your money for a maintenance contract - which would be fraud if they
*knew* they couldn't get spares. [There are lots of on-line sources of
boiler spares. It wouldn't do any harm to line up possible sources of PCBs
(if applicable), fans (if applicable), thermostats, gas valves etc.]

Updating your system will cost quite a lot of money. Not only will you need
a new boiler but you will also need to modify the pipework and add a lot of
controls - zone valves, tank stat, TRVs, etc. to comply with the latest
regs. BUT, having done it, you will save a *lot* of fuel. Modern boilers are
much more efficient than 20-year-old models and, coupled with better
controls, you'll achieve the same or better comfort levels with a lot less
gas.

So it *is* worth doing - but you can choose your own time to do it.
--
Cheers,
Set Square
______
Please reply to newsgroup. Reply address is invalid.

On 12 Jan 2005, Set Square wrote
In an earlier contribution to this discussion,
Roger wrote:

I have a 20 years old Glow-worm Spacesaver wall boiler which
works fine, providing pumped CH and gravity DHW.
B/Gas 3 star engineers keep telling me the they can "no longer
guarantee to be able to source spares"...ie a sales ploy to sell
a new boiler.

Our local council are supplying discounted high efficiency
boilers as a greening initiative, but I reckon the bill will be
£2k with fitting and maybe mods to the exisiting system.
Any of you experts got any impartial advice ?
My gut instinct is to try and source spares for my existing
boiler to keep it going as long as possible.
What do you think.?

I would update the system at a time of *my* choosing, and
certainly *not* employ BG to do it.

-snip-

So it *is* worth doing - but you can choose your own time to do
it.

Agreed.

As an aside, I've just had a conversation with my boiler service guy
(very local -- I know him well, as he lives three doors away), who was
saying that from (April?), new installations will have to use
condensing boilers, and conventional boilers like mine (which is 7 or 8
years old) will no longer be installed.

He understands the efficiency reasoning behind this -- although, as he
noted, placing a condensing boiler on an old system can reduce the
efficiency to the point where it's not actually condensing -- but
mentioned that he's quite busy at the moment installing conventional
boilers for people who want to beat the deadline for the new regs.

--
Cheers,
Harvey

"Roger" wrote in message ...
I have a 20 years old Glow-worm Spacesaver wall boiler which works fine,
providing pumped CH and gravity DHW.
B/Gas 3 star engineers keep telling me the they can "no longer guarantee
to
be able to source spares"...ie a sales ploy to sell a new boiler.
Our local council are supplying discounted high efficiency boilers as a
greening initiative, but I reckon the bill will be £2k with fitting and
maybe mods to the exisiting system.
Any of you experts got any impartial advice ?
My gut instinct is to try and source spares for my existing boiler to keep
it going as long as possible.
What do you think.?

Not a fan of BG service but after 20 years they may have a point. If you
decide to go the new boiler route which really means new system route you
have a choice in the open market. No need to accept BGs offer. Sadly its
a hard lesson, the BG money is down the drain now, only you can decide if
the unlimited call-out peace of mind was worth it.

My view would be that the existing boiler is written down and expenditure
beyond the odd thermocouple isn't worth it. Start planning now for a
replacement, but not during the winter heating season.

Don't know where BG get this unlimited call-out idea from, unless it is
their own duff maitenance. On balance, most appliances of any description
these days don't require unlimited call-outs, so the BG offer can't be good
value. Bank the savings.

Jim A

"Roger" wrote in message ...
I have a 20 years old Glow-worm Spacesaver wall boiler which works fine,
providing pumped CH and gravity DHW.
B/Gas 3 star engineers keep telling me the they can "no longer guarantee
to
be able to source spares"...ie a sales ploy to sell a new boiler.
Our local council are supplying discounted high efficiency boilers as a
greening initiative, but I reckon the bill will be £2k with fitting and
maybe mods to the exisiting system.
Any of you experts got any impartial advice ?
My gut instinct is to try and source spares for my existing boiler to keep
it going as long as possible.
What do you think.?

Not a fan of BG service but after 20 years they may have a point. If you
decide to go the new boiler route which really means new system route you
have a choice in the open market. No need to accept BGs offer. Sadly its
a hard lesson, the BG money is down the drain now, only you can decide if
the unlimited call-out peace of mind was worth it.

My view would be that the existing boiler is already written down and
expenditure
beyond the odd thermocouple isn't worth it. Start planning now for a
replacement, but not during the winter heating season.

Don't know where BG get this unlimited call-out idea from, unless it is
their own duff maitenance. On balance, most appliances of any description
these days don't require unlimited call-outs, so the BG offer can't be good
value. Suggest you bank the savings next time.

Jim A

In an earlier contribution to this discussion,
Harvey Van Sickle wrote:


As an aside, I've just had a conversation with my boiler service guy
(very local -- I know him well, as he lives three doors away), who was
saying that from (April?), new installations will have to use
condensing boilers, and conventional boilers like mine (which is 7 or
8 years old) will no longer be installed.

AIUI, boilers will have to be capable of at least a certain efficiency
level - which condensing boilers can meet more easily. I'm not sure that
it's necessarily *impossible* to meet with a non-condensing boiler?

He understands the efficiency reasoning behind this -- although, as he
noted, placing a condensing boiler on an old system can reduce the
efficiency to the point where it's not actually condensing

*Can* but not necessarily *does*. Systems designed to run at a high radiator
temperature won't allow the boiler the condense when running at that
temperature. But this will only happen in very cold weather. In milder
conditions, the rads can run cooler - but be on more of the time - which
*will* allow the boiler to condense.
--
Cheers,
Set Square
______
Please reply to newsgroup. Reply address is invalid.

On 12 Jan 2005, Set Square wrote
In an earlier contribution to this discussion,
Harvey Van Sickle wrote:


As an aside, I've just had a conversation with my boiler service
guy (very local -- I know him well, as he lives three doors
away), who was saying that from (April?), new installations will
have to use condensing boilers, and conventional boilers like
mine (which is 7 or 8 years old) will no longer be installed.

AIUI, boilers will have to be capable of at least a certain
efficiency level - which condensing boilers can meet more easily.
I'm not sure that it's necessarily *impossible* to meet with a
non-condensing boiler?

That would be interesting to know -- but from my friend's statement it
sounded as if the manufacturers werent' going down that road. (He
mentioned that the only non-condensing boiler which was currently
available without jumping through hoops was a floor-standing rather
than wall-mounted model.)

He understands the efficiency reasoning behind this -- although,
as he noted, placing a condensing boiler on an old system can
reduce the efficiency to the point where it's not actually
condensing

*Can* but not necessarily *does*. [explanation snipped]

Yes, right: he was quite clear that it was system-dependent. He was
just making the point that increased efficiency depends on more than
simply hooking up a condensing boiler to all existing systems.

--
Cheers,
Harvey

"Harvey Van Sickle" wrote in message
...

As an aside, I've just had a conversation
with my boiler service guy
(very local -- I know him well, as he
lives three doors away), who was
saying that from (April?), new installations
will have to use condensing boilers,
and conventional boilers like mine (which
is 7 or 8 years old) will no longer be installed.

He understands the efficiency reasoning
behind this -- although, as he
noted, placing a condensing boiler on
an old system can reduce the
efficiency to the point where it's not actually
condensing

Not so. Modern condesning boilers have load compenstion modulating control
to lower the return temperaure to the building heat load. Over 90% of the
time a normal system will be on part load, so not really an issue. Maker
have designed boioer for the replacement market.

-- but mentioned that he's quite busy
at the moment installing conventional
boilers for people who want to beat
the deadline for the new regs.

Stupid idea, condensing boilers are well worth it over regular boilers.
They are virtually the same, only one has a larger heat exchanger and a
condensate drain.....and saves lots of gas.

"Harvey Van Sickle" wrote in message
...

Yes, right: he was quite clear that it was system-dependent. He was
just making the point that increased efficiency depends on more than
simply hooking up a condensing boiler to all existing systems.

Not so. Just get the right boiler and simple replacement and efficiencies
far greater than before.

In an earlier contribution to this discussion,
Harvey Van Sickle wrote:


Yes, right: he was quite clear that it was system-dependent. He was
just making the point that increased efficiency depends on more than
simply hooking up a condensing boiler to all existing systems.

Having said that, a new boiler - condensing or not - is going to be a damn
sight more efficient than a 20-year-old model anyway!

Personally, I wouldn't want it *too* efficient. Stray heat from my boiler is
the *only* heat I curently have in my utility room!
--
Cheers,
Set Square
______
Please reply to newsgroup. Reply address is invalid.

"Set Square" wrote in message
...

AIUI, boilers will have to be capable
of at least a certain efficiency
level - which condensing boilers
can meet more easily. I'm not sure that
it's necessarily *impossible* to meet
with a non-condensing boiler?

SEDBUK has the best regular at about 80.5%. The "peak" efficiency can be
over 90%.

If you engineer the system to get the most from a regular boiler you can be
in condensing boiler efficiencies. But you have to know what you are doing.
A regular boiler is designed "not" to condense.

1. A blending valve is fitted on the flow and return ensuring the boiler
return never gets below say about 55C, which below condensing occurs

2. The boiler stat is set to 10C above so at 65C

3. The cylinder coil and rads are designed and sized for this 10C
differential and flow of 65C and return of 55C

Doing the above will improve a regular boilers efficiency substantially.
Just having the blending valve and setting the boiler to 65C will do
wonders, as in most homes the rads are oversized for most of the operation
time. They are sized for the worst case example of -1 to -3C outside. If
it is really cold then turn the boiler stat up to full, then back down to
65C when it warms up outside. Simple to do, will protect the boiler from
condensation and improve efficiency.

Hi guys...thanks very much for the advice....much appreciated.
For information, I have just spoken to tech support at Glow-worm who assure
me that all spares are available for this boiler and will be for the
foreseeable!
His comment was that BG want me to replace the boiler before it starts
giving problems and costing BG money. (ie I'm on a fixed price contract).
His advice is to run it until it drops, which could be years.
He also said "there is b***er all to go wrong in those simple old boilers,
unlike the new condensing jobbers which have hundreds of parts to go wrong!"
So I'll stay where I am........
Thanks again
Roger


"Roger" wrote in message ...
I have a 20 years old Glow-worm Spacesaver wall boiler which works fine,
providing pumped CH and gravity DHW.
B/Gas 3 star engineers keep telling me the they can "no longer guarantee
to
be able to source spares"...ie a sales ploy to sell a new boiler.
Our local council are supplying discounted high efficiency boilers as a
greening initiative, but I reckon the bill will be £2k with fitting and
maybe mods to the exisiting system.
Any of you experts got any impartial advice ?
My gut instinct is to try and source spares for my existing boiler to keep
it going as long as possible.
What do you think.?

"Set Square" wrote in message
...
In an earlier contribution to this discussion,
Harvey Van Sickle wrote:

Yes, right: he was quite clear that it was system-dependent. He was
just making the point that increased efficiency depends on more than
simply hooking up a condensing boiler to all existing systems.

Having said that, a new boiler - condensing or not - is going to be a damn
sight more efficient than a 20-year-old model anyway!

Bills will drop by about 40%. It is worth keeping this boiler for a while
and see if the condensers drop in price after April.

"Roger" wrote in message ...
Hi guys...thanks very much for the advice....much appreciated.
For information, I have just spoken to tech support at Glow-worm who
assure
me that all spares are available for this boiler and will be for the
foreseeable!
His comment was that BG want me to replace the boiler before it starts
giving problems and costing BG money. (ie I'm on a fixed price contract).
His advice is to run it until it drops, which could be years.
He also said "there is b***er all to go wrong in those simple old
boilers,
unlike the new condensing jobbers which have hundreds of parts to go
wrong!"

New non-condensing boilers have just as many parts to go wrong. It is worth
your while doing the figures on payback as you gas bill will drop like a
stone. The techie mans opinion is well, just his opinion, not the
definitive way to go.

A new modulating boiler will give superior comfort condistions and give
greater DHW recovery. So, you also have greater advantages in living with a
new system.

In article ,
"Set Square" writes:
In an earlier contribution to this discussion,
Harvey Van Sickle wrote:


Yes, right: he was quite clear that it was system-dependent. He was
just making the point that increased efficiency depends on more than
simply hooking up a condensing boiler to all existing systems.

Having said that, a new boiler - condensing or not - is going to be a damn
sight more efficient than a 20-year-old model anyway!

Personally, I wouldn't want it *too* efficient. Stray heat from my boiler is
the *only* heat I curently have in my utility room!

The area where they are significantly more efficient is less
waste heat going out of the flue as steam, which probably does
little to heat your utility room unless there's a long length of
exposed flue. It's interesting to watch the condensate trickling
out of a condensing boiler and think to yourself that you used to
be wasting the energy required to boil all that away and send it
up the flue.

You can always have an extra radiator fitted when the boiler is
replaced. (If you have any radiators which are currently too small
for their rooms, you should think about upgrading those when you
switch to a condensing boiler, and you might be able to swap a
small one which becomes spare into the utility room.)

--
Andrew Gabriel

"IMM" wrote in message
...

"Roger" wrote in message ...
Hi guys...thanks very much for the advice....much appreciated.
For information, I have just spoken to tech support at Glow-worm who
assure
me that all spares are available for this boiler and will be for the
foreseeable!
His comment was that BG want me to replace the boiler before it starts
giving problems and costing BG money. (ie I'm on a fixed price contract).
His advice is to run it until it drops, which could be years.
He also said "there is b***er all to go wrong in those simple old
boilers,
unlike the new condensing jobbers which have hundreds of parts to go
wrong!"

New non-condensing boilers have just as many parts to go wrong. It is
worth
your while doing the figures on payback as you gas bill will drop like a
stone. The techie mans opinion is well, just his opinion, not the
definitive way to go.

A new modulating boiler will give superior comfort condistions and give
greater DHW recovery. So, you also have greater advantages in living with
a
new system.

Not convinced of the economics of boiler replacement, other than if
terminal. A mate of mine had his old back boiler replaced and pipework
modified for fully pumped wall mounted jobby, cost £2.5K, job nicely done
but bills dropped from about £220 a year to £170 a year which gives a 50
year payback time !!!

"Andrew Gabriel" wrote in message
...
In article ,
"Set Square" writes:
In an earlier contribution to this discussion,
Harvey Van Sickle wrote:


Yes, right: he was quite clear that it was system-dependent. He was
just making the point that increased efficiency depends on more than
simply hooking up a condensing boiler to all existing systems.

Having said that, a new boiler - condensing or not - is going to be a
damn
sight more efficient than a 20-year-old model anyway!

Personally, I wouldn't want it *too* efficient. Stray heat from my
boiler is
the *only* heat I curently have in my utility room!

The area where they are significantly more efficient is less
waste heat going out of the flue as steam, which probably does
little to heat your utility room unless there's a long length of
exposed flue. It's interesting to watch the condensate trickling
out of a condensing boiler and think to yourself that you used to
be wasting the energy required to boil all that away and send it
up the flue.

You can always have an extra radiator fitted when the boiler is
replaced. (If you have any radiators which are currently too small
for their rooms, you should think about upgrading those when you
switch to a condensing boiler, and you might be able to swap a
small one which becomes spare into the utility room.)

Don't reuse rads. They contain rust and the likes. Not worth it as they
are so cheap..

In an earlier contribution to this discussion,
Ian Middleton wrote:


Not convinced of the economics of boiler replacement, other than if
terminal. A mate of mine had his old back boiler replaced and pipework
modified for fully pumped wall mounted jobby, cost £2.5K, job nicely
done but bills dropped from about £220 a year to £170 a year which
gives a 50 year payback time !!!


That's a very valid point - even allowing for a rapid rise in gas prices,
which will shorten the payback period a bit.
--
Cheers,
Set Square
______
Please reply to newsgroup. Reply address is invalid.

"Set Square" wrote in message
...
In an earlier contribution to this discussion,
Ian Middleton wrote:


Not convinced of the economics of boiler replacement, other than if
terminal. A mate of mine had his old back boiler replaced and pipework
modified for fully pumped wall mounted jobby, cost £2.5K, job nicely
done but bills dropped from about £220 a year to £170 a year which
gives a 50 year payback time !!!


That's a very valid point - even allowing for a rapid rise in gas prices,
which will shorten the payback period a bit.

I'm sure this man didn't change a back boiler just to save £50 a year. He
did it to get rid of the thing from his living room. Then there is the
comfort that a new boiler gives.

"IMM" wrote in message
...


A new modulating boiler will give superior comfort condistions and give
greater DHW recovery.

I can understand a condensing combi being potentially a very efficient
package if a combi is what is wanted, but DHW storage requires the mean
water temperature to be above 60deg and a themal store temperature to be at
the design temperature. I've seen 75deg mentioned. In a mainstream
domestic market boiler that can only be achieved by the boiler flow setpoint
being at least the required temperature year round. That reduces the
condensing savings considerably, massively if useing a thermal store.

Jim A

"Jim Alexander" wrote in message
...

"IMM" wrote in message
...


A new modulating boiler will give
superior comfort condistions and give
greater DHW recovery.

I can understand a condensing combi being
potentially a very efficient
package if a combi is what is wanted, but
DHW storage requires the mean
water temperature to be above 60deg and
a themal store temperature to be at
the design temperature. I've seen 75deg
mentioned. In a mainstream domestic
market boiler that can only be achieved by
the boiler flow setpoint being at least the
required temperature year round. That
reduces the condensing savings considerably,
massively if useing a thermal store.

Couple a non-condenser to a thermal store and efficiencies rise to the mid
to late 80% as the operational condition is stable and very predictable.
Have a blending valve ensuring the 11C differential and the 80C flow is
virtually guaranteed. SEDBUK's seasonal figures do not apply. Part load
does not apply.

Condensing boilers coupled to thermal stores, where the store is to be 80C,
do not perform much better than a good regular boiler, and cost
substantially more (I know the price is dropping like a stone). Have a
larger thermal store, or better a heat bank, and store temp of 76C, as some
do, and couple a condensing boiler with 22C temp diff with the load
compensation control switched off then a 54C return temp is guaranteed using
a blending valve, and efficiencies rise with the condenser.

The beauty of using a thermal store is that a boiler can be quite basic and
simple. The Quantum boilers Heatsave is ideal as it does not modulate.
http://www.quantum-boilers.co.uk/index1.htm This is a good quality boiler.

Initially condensing boilers were thought not to be suitable for thermal
stores. Not entirely correct as a condenser will always be more efficient
as it merely has a larger heat exchanger. The store makers made them larger
and dropped the operating temperature to 75-76C and used blending valves on
the boioer flow and return ensuring low return temps to the boiler most of
operational time. Boiler makers produced a wider Delta T. Then they were
far more efficient, but not to the maximum efficiency that could be obtained
from a condensing boiler.

The beauty of using a blending valve on the boiler flow and return on a heat
bank or thermal store is that the water in the store only requires one pass
through the boiler for the store to be up to temp. This makes the setup
quite efficient all around.

The wider the Delta T on the boiler the better for efficiency. Makers will
state a Delta T of say 22C, contact their Tech dept and they will usually go
4-5C over that, so a regulated condensing return of 50C can be achieved in
many cases increasing overall efficiency.

The message
from "Ian Middleton" contains these words:

Not convinced of the economics of boiler replacement, other than if
terminal. A mate of mine had his old back boiler replaced and pipework
modified for fully pumped wall mounted jobby, cost £2.5K, job nicely done
but bills dropped from about £220 a year to £170 a year which gives a 50
year payback time !!!

Figures won't impress dIMM, he just doesn't understand simple arithmetic.

As to the example above I doubt if any likely scenario could feature a
much better saving but the saving here on the gas bill is only £50 per
year, about 23% at current prices, hardly more than half the 40% dIMM
constantly bangs on about.

Meanwhile £2.5K could have been earning say 5% (£125 per year) until
really needed. If borrowed the situation would be much worse.

--
Roger

"Roger" wrote in message
k...
The message
from "Ian Middleton" contains these words:

Not convinced of the economics of boiler replacement, other than if
terminal. A mate of mine had his old back boiler replaced and pipework
modified for fully pumped wall mounted jobby, cost £2.5K, job nicely
done
but bills dropped from about £220 a year to £170 a year which gives a 50
year payback time !!!

Figures won't impress

snip drivel

"Ian Middleton" wrote in message
...

Not convinced of the economics of boiler
replacement, other than if
terminal.

In some areas a new boiler will make a house certainly sell quicker, so
maybe worth it just for that.

Harvey Van Sickle wrote:

As an aside, I've just had a conversation with my boiler service guy
(very local -- I know him well, as he lives three doors away), who was
saying that from (April?), new installations will have to use
condensing boilers, and conventional boilers like mine (which is 7 or 8
years old) will no longer be installed.

Even under the new rules, it will still be possible to fit non
condensers under certain circumstances. There is a "scoring" system that
you use to tot up points attributed to various factors (distance to flue
terminal, availability of condensate drain etc). If you reach a big
enough score, then you are allowed to install a less efficient boiler.

He understands the efficiency reasoning behind this -- although, as he
noted, placing a condensing boiler on an old system can reduce the
efficiency to the point where it's not actually condensing -- but
mentioned that he's quite busy at the moment installing conventional
boilers for people who want to beat the deadline for the new regs.

I was "informed" by my mother a while ago that according to a programme
broadcast on radio 4 a while back, there was no point in my installing a
condensing boiler! (apparently someone was arguing that fitting
condensing boilers to old systems would have no benefit for many of the
same reasons as you chap seems to be suggesting).

It took a while to explain all the various reasons why that argument was
flawed, very simplistic and ignored most of the factors!

--
Cheers,

John.

/================================================== ===============\
| Internode Ltd - http://www.internode.co.uk |
|-----------------------------------------------------------------|
| John Rumm - john(at)internode(dot)co(dot)uk |
\================================================= ================/

In article ,
"IMM" writes:

In some areas a new boiler will make a house certainly sell quicker,
so maybe worth it just for that.

Rubbish. It's rare for anyone purchasing a house to have
any clue if the heating works or not before moving in.

--
Andrew Gabriel

"Andrew Gabriel" wrote in message
...
In article ,
"IMM" writes:

In some areas a new boiler will make a house certainly sell quicker,
so maybe worth it just for that.

Rubbish. It's rare for anyone purchasing a house to have
any clue if the heating works or not before moving in.

Absolute tripe. I know in some areas the estate agents highlight that an
economic gas condensing boiler is fitted. When people view and see a brand
new boiler that is certainly is a selling point. That means no expenditure
on heating for many years to come.

So, you think that a kitchen with conventional flued boiler that looks 30
years old will be treated the same as one with a brand new cheap to run
condenser on the wall? Get real.

As the property TV progs have shown, selling a house straight away can mean
£1000s saved or gained.

On Wed, 12 Jan 2005 20:51:49 +0000, Andrew Gabriel wrote:

In article ,
"IMM" writes:

In some areas a new boiler will make a house certainly sell quicker,
so maybe worth it just for that.

Rubbish. It's rare for anyone purchasing a house to have
any clue if the heating works or not before moving in.

We have had this thread before.

IIRC the opinion of the Estate Agent posters here was that any working
heating system was a view equally and a broken one a serious defect (with
more than it's fixing price implicated in the purchase price).




--
Ed Sirett - Property maintainer and registered gas fitter.
The FAQ for uk.diy is at 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

On Wed, 12 Jan 2005 18:51:47 -0000, "IMM" wrote:


"Ian Middleton" wrote in message
...

Not convinced of the economics of boiler
replacement, other than if
terminal.

In some areas a new boiler will make a house certainly sell quicker, so
maybe worth it just for that.


********.

This is a long way down the priority list.

It's worth having a high efficiency boiler, but it is not a valid
argument to say that house buyers are attracted to the extent you
imply.

Be honest about the benefits.




--

..andy

To email, substitute .nospam with .gl

On Wed, 12 Jan 2005 14:11:20 -0000, "IMM" wrote:


"Set Square" wrote in message
...
In an earlier contribution to this discussion,
Harvey Van Sickle wrote:

Yes, right: he was quite clear that it was system-dependent. He was
just making the point that increased efficiency depends on more than
simply hooking up a condensing boiler to all existing systems.

Having said that, a new boiler - condensing or not - is going to be a damn
sight more efficient than a 20-year-old model anyway!

Bills will drop by about 40%. It is worth keeping this boiler for a while
and see if the condensers drop in price after April.



Oh cobblers.

A condensing boiler will achieve up to 30% improvement over a cast
iron machine, but 40% is overstating it and devaluing the proposition.



--

..andy

To email, substitute .nospam with .gl

"Andy Hall" wrote in message
...
On Wed, 12 Jan 2005 18:51:47 -0000, "IMM" wrote:


"Ian Middleton" wrote in message
...

Not convinced of the economics of boiler
replacement, other than if
terminal.

In some areas a new boiler will make a house certainly sell quicker, so
maybe worth it just for that.


********.

This is a long way down the priority list.

It's worth having a high efficiency boiler, but it is not a valid
argument to say that house buyers are attracted to the extent you
imply.

Be honest about the benefits.

See other post on this.

On Wed, 12 Jan 2005 17:50:00 -0000, "IMM" wrote:



Couple a non-condenser to a thermal store and efficiencies rise to the mid
to late 80% as the operational condition is stable and very predictable.
Have a blending valve ensuring the 11C differential and the 80C flow is
virtually guaranteed. SEDBUK's seasonal figures do not apply. Part load
does not apply.

Condensing boilers coupled to thermal stores, where the store is to be 80C,
do not perform much better than a good regular boiler, and cost
substantially more (I know the price is dropping like a stone). Have a
larger thermal store, or better a heat bank, and store temp of 76C, as some
do, and couple a condensing boiler with 22C temp diff with the load
compensation control switched off then a 54C return temp is guaranteed using
a blending valve, and efficiencies rise with the condenser.

The beauty of using a thermal store is that a boiler can be quite basic and
simple. The Quantum boilers Heatsave is ideal as it does not modulate.
http://www.quantum-boilers.co.uk/index1.htm This is a good quality boiler.

Initially condensing boilers were thought not to be suitable for thermal
stores. Not entirely correct as a condenser will always be more efficient
as it merely has a larger heat exchanger. The store makers made them larger
and dropped the operating temperature to 75-76C and used blending valves on
the boioer flow and return ensuring low return temps to the boiler most of
operational time. Boiler makers produced a wider Delta T. Then they were
far more efficient, but not to the maximum efficiency that could be obtained
from a condensing boiler.

The beauty of using a blending valve on the boiler flow and return on a heat
bank or thermal store is that the water in the store only requires one pass
through the boiler for the store to be up to temp. This makes the setup
quite efficient all around.

The wider the Delta T on the boiler the better for efficiency. Makers will
state a Delta T of say 22C, contact their Tech dept and they will usually go
4-5C over that, so a regulated condensing return of 50C can be achieved in
many cases increasing overall efficiency.



This is a distortion of reality.

It is the case that a condensing boiler may well be more efficient
than a conventional one at the higher end of the temperature range.

However, you are implying that by fine tuning the operating
temperature on the flow side to 76 degrees, that something wonderful
happens, the angels sing and you can be up to your chin in a bath of
10 litres.

There is not a sudden Holy Grail to be achieved at 52-55 degrees
return temperature with a condensing boiler. All that happens is
that the efficiency curve takes a steeper slope.

What you are actually describing is a compromise which in practice
makes very little difference from the perspective of whether
condensing is happening or not.

In other words, miracles don't suddenly happen at 0.1 degrees below
the dew point.





--

..andy

To email, substitute .nospam with .gl

"Andy Hall" wrote in message
...
On Wed, 12 Jan 2005 14:11:20 -0000, "IMM" wrote:


"Set Square" wrote in message
...
In an earlier contribution to this discussion,
Harvey Van Sickle wrote:

Yes, right: he was quite clear that it was system-dependent. He was
just making the point that increased efficiency depends on more than
simply hooking up a condensing boiler to all existing systems.

Having said that, a new boiler - condensing or not - is going to be a
damn
sight more efficient than a 20-year-old model anyway!

Bills will drop by about 40%. It is worth keeping this boiler for a
while
and see if the condensers drop in price after April.

Oh cobblers.

Wrong ng.

A condensing boiler will achieve
up to 30% improvement over a cast
iron machine, but 40% is overstating
it and devaluing the proposition.

Not so. A 50-55% efficient cast-iron clunker replaced by a high efficiency
condenser with TRVs, and ate-of the art controls, quick recovery cylinder
etc, will give approx 40% (older boilers are nor suited to quick recovery
cylinders as they cause the boiler to condense). Remember the old boilers
efficiency would have tailed off over the years. I have come across this
sort of efficiency hype.

There you are. easy.

"Andy Hall" wrote in message
...
On Wed, 12 Jan 2005 17:50:00 -0000, "IMM" wrote:



Couple a non-condenser to a thermal store and efficiencies rise to the
mid
to late 80% as the operational condition is stable and very predictable.
Have a blending valve ensuring the 11C differential and the 80C flow is
virtually guaranteed. SEDBUK's seasonal figures do not apply. Part load
does not apply.

Condensing boilers coupled to thermal stores, where the store is to be
80C,
do not perform much better than a good regular boiler, and cost
substantially more (I know the price is dropping like a stone). Have a
larger thermal store, or better a heat bank, and store temp of 76C, as
some
do, and couple a condensing boiler with 22C temp diff with the load
compensation control switched off then a 54C return temp is guaranteed
using
a blending valve, and efficiencies rise with the condenser.

The beauty of using a thermal store is that a boiler can be quite basic
and
simple. The Quantum boilers Heatsave is ideal as it does not modulate.
http://www.quantum-boilers.co.uk/index1.htm This is a good quality
boiler.

Initially condensing boilers were thought not to be suitable for thermal
stores. Not entirely correct as a condenser will always be more
efficient
as it merely has a larger heat exchanger. The store makers made them
larger
and dropped the operating temperature to 75-76C and used blending valves
on
the boioer flow and return ensuring low return temps to the boiler most
of
operational time. Boiler makers produced a wider Delta T. Then they
were
far more efficient, but not to the maximum efficiency that could be
obtained
from a condensing boiler.

The beauty of using a blending valve on the boiler flow and return on a
heat
bank or thermal store is that the water in the store only requires one
pass
through the boiler for the store to be up to temp. This makes the setup
quite efficient all around.

The wider the Delta T on the boiler the better for efficiency. Makers
will
state a Delta T of say 22C, contact their Tech dept and they will usually
go
4-5C over that, so a regulated condensing return of 50C can be achieved
in
many cases increasing overall efficiency.

This is a distortion of reality.

What is he on about now?

It is the case that a condensing
boiler may well be more efficient
than a conventional one at the higher
end of the temperature range.

and it is.

However, you are implying that by
fine tuning the operating
temperature on the flow side to
76 degrees, that something wonderful
happens, the angels sing and you can
be up to your chin in a bath of 10 litres.

uh?

Lower the overall running temperature and efficiency rises.

There is not a sudden Holy
Grail to be achieved at 52-55 degrees
return temperature with a condensing
boiler.

No one said there was.

All that happens is
that the efficiency curve takes a steeper
slope.

...and that is does.

What you are actually describing is a
compromise which in practice
makes very little difference from
the perspective of whether
condensing is happening or not.

No. What I am describing is increasing efficiency by lower the overall
running temperature. Engineering the system for efficiency.

In other words, miracles don't suddenly
happen at 0.1 degrees below
the dew point.

No said miracles happen just below dew point. Please read again.

Ed Sirett wrote:

We have had this thread before.

.... many times, many many times ...

--
Andy

IMM wrote:

Condensing boilers coupled to thermal stores, where the store is to be 80C,
do not perform much better than a good regular boiler, and cost
substantially more (I know the price is dropping like a stone). Have a
larger thermal store, or better a heat bank, and store temp of 76C, as some
do, and couple a condensing boiler with 22C temp diff with the load
compensation control switched off then a 54C return temp is guaranteed using
a blending valve, and efficiencies rise with the condenser.

Now this bit is actualy progress...

The beauty of using a thermal store is that a boiler can be quite basic and
simple. The Quantum boilers Heatsave is ideal as it does not modulate.
http://www.quantum-boilers.co.uk/index1.htm This is a good quality boiler.

A few weeks back I seem to recall you trying to tell us that sticking a
store in between boiler and rads was always a "good thing", and that it
would raise efficiency. ISTR a number of people pointing out that while
this may well be the case for a dumb non modulating boiler, with a most
modern boilers all you were doing was bolloxing the boilers closed loop
control system by sticking a large energy storage term into the sums,
that would only serve to upset the boilers ability to load compensate.

Well done IMM, you are beginning to pick some of this stuff up it seems.

--
Cheers,

John.

/================================================== ===============\
| Internode Ltd - http://www.internode.co.uk |
|-----------------------------------------------------------------|
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The message
from "IMM" contains these words:

You should read what I write. Sorry "understand" what I write.

That's a laugh. dIMM doesn't understand what he writes himself so why
should he expect anyone else to.

--
Roger

"Roger" wrote in message
k...
The message
from "IMM" contains these words:

You should read what I write. Sorry "understand" what I write.

That's a

snip drivel

On Thu, 13 Jan 2005 00:05:17 +0000, Andy Hall wrote:

On Wed, 12 Jan 2005 14:11:20 -0000, "IMM" wrote:


"Set Square" wrote in message
...
In an earlier contribution to this discussion,
Harvey Van Sickle wrote:

Yes, right: he was quite clear that it was system-dependent. He was
just making the point that increased efficiency depends on more than
simply hooking up a condensing boiler to all existing systems.

Having said that, a new boiler - condensing or not - is going to be a damn
sight more efficient than a 20-year-old model anyway!

Bills will drop by about 40%. It is worth keeping this boiler for a while
and see if the condensers drop in price after April.


Even BG only say 35%.
As posted elsewhere, based on actual installations, including my own.
A 30% saving is achievable as an upper bound.



--
Ed Sirett - Property maintainer and registered gas fitter.
The FAQ for uk.diy is at 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