Brief background; visiting a friend with very old central heating -
reminds me of what was in our last house when we moved in in 1984.

An old Glow-worm 85 100 floor standing lump of iron. Kettles like a really
kettly kettle. Radiators of various vintages, some with suspiciously cool
bottoms.

It hasn't been serviced recently (then again, these are so simple that
there isn't much to service compared to modern boilers). This also
suggests it might do with a flush and some inhibitor.

I suspect a power flush might improve the effectiveness of the radiators.

This is a large long and thin 4 bedroom bungalow with a lot of glass,
patio doors, plastic roof conservatory as part of the dining room. So
probably not that thermally efficient.

I am assuming that a new central heating system will cost more than
£4,500; possibly quite a bit more given the length of the pipe runs.

Just wondering how long it normally takes to recoup the cost of a new
highly efficient system through fuel savings.

For example, a £4,500 system would need to save £450 a year to pay back
over 10 years.

I expect the costs to be higher and the savings per year to be perhaps a
little less.

When you get past 60 long term investment looks less attractive,
especially with a pay back tome of 15-20 years.

Piece of string question but just pondering.

Cheers

Dave R

David wrote:
Brief background; visiting a friend with very old central heating -
reminds me of what was in our last house when we moved in in 1984.

An old Glow-worm 85 100 floor standing lump of iron. Kettles like a really
kettly kettle. Radiators of various vintages, some with suspiciously cool
bottoms.

It hasn't been serviced recently (then again, these are so simple that
there isn't much to service compared to modern boilers). This also
suggests it might do with a flush and some inhibitor.

I suspect a power flush might improve the effectiveness of the radiators.

This is a large long and thin 4 bedroom bungalow with a lot of glass,
patio doors, plastic roof conservatory as part of the dining room. So
probably not that thermally efficient.

I am assuming that a new central heating system will cost more than
£4,500; possibly quite a bit more given the length of the pipe runs.

Just wondering how long it normally takes to recoup the cost of a new
highly efficient system through fuel savings.

For example, a £4,500 system would need to save £450 a year to pay back
over 10 years.

I expect the costs to be higher and the savings per year to be perhaps a
little less.

When you get past 60 long term investment looks less attractive,
especially with a pay back tome of 15-20 years.

Piece of string question but just pondering.

Cheers

Dave R

It rarely makes financial sense to replace an old boiler with a new one
on an old system as the operating temperature generally need to be high
to get the rads working properly and the boiler rarely work in
condensing mode so the expected savings won't be achieved.

If you can still get the gaskets for the old boiler then stripping that
down and a thorough clean inside the HE to stop the kettling and
re-assembling would be low cost high effort diy solution or go the whole
hog and new boiler, new oversize rads, weather compensating controls and
mains pressure DHW and maybe solar thermal input to DHW will spend the
cash, leave your feeling smug and if you are lucky 10 years service out
of the boiler and 20% off the gas bill overall.

On Sunday, 13 November 2016 16:32:40 UTC, David WE Roberts (Google) wrote:
Brief background; visiting a friend with very old central heating -
reminds me of what was in our last house when we moved in in 1984.

An old Glow-worm 85 100 floor standing lump of iron. Kettles like a really
kettly kettle.

Turn boiler stat down, clean system with acidic cleaner or fix poor primary water flow rate.

Radiators of various vintages, some with suspiciously cool
bottoms.

can be taken off 1 by 1 & flushed out.

It hasn't been serviced recently (then again, these are so simple that
there isn't much to service compared to modern boilers). This also
suggests it might do with a flush and some inhibitor.

I suspect a power flush might improve the effectiveness of the radiators.

This is a large long and thin 4 bedroom bungalow with a lot of glass,
patio doors, plastic roof conservatory as part of the dining room. So
probably not that thermally efficient.

I am assuming that a new central heating system will cost more than
£4,500; possibly quite a bit more given the length of the pipe runs.

Just wondering how long it normally takes to recoup the cost of a new
highly efficient system through fuel savings.

For example, a £4,500 system would need to save £450 a year to pay back
over 10 years.

I expect the costs to be higher and the savings per year to be perhaps a
little less.

When you get past 60 long term investment looks less attractive,
especially with a pay back tome of 15-20 years.

Piece of string question but just pondering.

Cheers

Dave R

I'm told cast iron lumps are around 65% efficient versus modern boilers of over 90%.


NT

In article ,
David wrote:
It hasn't been serviced recently (then again, these are so simple that
there isn't much to service compared to modern boilers).

Not sure about that at all. Older boilers are likely to need a good clean
more often than modern ones. The pilot light cleaned and adjusted.

Servicing these days seems to consist of more just checking everything is
working OK rather than doing anything

--
*When the going gets tough, the tough take a coffee break *

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

In article ,
David writes:
Brief background; visiting a friend with very old central heating -
reminds me of what was in our last house when we moved in in 1984.

An old Glow-worm 85 100 floor standing lump of iron. Kettles like a really
kettly kettle. Radiators of various vintages, some with suspiciously cool
bottoms.

It hasn't been serviced recently (then again, these are so simple that
there isn't much to service compared to modern boilers). This also
suggests it might do with a flush and some inhibitor.

If it's not room-sealed, then it really should be checked every
year, as it can suddenly build up soot through the heat exchanger
which causes incomplete combustion and emission of carbon monoxide.

Also, in such a system, a flush and inhibitor might clear out some
scale sealing leaks, particularly in the boiler itself.

Recently knocked up a Pi-based controller for a Kingfisher cast-iron
lump, to try and improve efficiency of an old system for a friend.
That has a pumped heating circuit, but a gravity hot water cylinder
coil. It didn't have a roomstat or cylinder stat originally - it does
now, and remote control/monitoring over the Internet.

--
Andrew Gabriel
[email address is not usable -- followup in the newsgroup]

In article , David
writes
Brief background; visiting a friend with very old central heating -
reminds me of what was in our last house when we moved in in 1984.

An old Glow-worm 85 100 floor standing lump of iron. Kettles like a really
kettly kettle. Radiators of various vintages, some with suspiciously cool
bottoms.

It hasn't been serviced recently (then again, these are so simple that
there isn't much to service compared to modern boilers). This also
suggests it might do with a flush and some inhibitor.

I suspect a power flush might improve the effectiveness of the radiators.

This is a large long and thin 4 bedroom bungalow with a lot of glass,
patio doors, plastic roof conservatory as part of the dining room. So
probably not that thermally efficient.

I am assuming that a new central heating system will cost more than
£4,500; possibly quite a bit more given the length of the pipe runs.

Just wondering how long it normally takes to recoup the cost of a new
highly efficient system through fuel savings.

For example, a £4,500 system would need to save £450 a year to pay back
over 10 years.

I expect the costs to be higher and the savings per year to be perhaps a
little less.

When you get past 60 long term investment looks less attractive,
especially with a pay back tome of 15-20 years.

Piece of string question but just pondering.

Cheers

Dave R
Well if you have £4500 sitting in the bank you'll be getting about £22
pa interest. So if you invest that money in a new boiler you will be
getting a better return on your money but you have converted a liquid
asset into a depreciating fixed one.
--
bert

On 13/11/2016 19:59, bert wrote:

Well if you have £4500 sitting in the bank you'll be getting about £22
pa interest. So if you invest that money in a new boiler you will be
getting a better return on your money but you have converted a liquid
asset into a depreciating fixed one.

Would there be a better return on spending that £4500 on solar panels?

Nothing wrong with upsetting TNP as long as you don't actually think it
will help save the planet.

On Sunday, 13 November 2016 18:55:56 UTC, Andrew Gabriel wrote:
In article ,
David writes:

Brief background; visiting a friend with very old central heating -
reminds me of what was in our last house when we moved in in 1984.

An old Glow-worm 85 100 floor standing lump of iron. Kettles like a really
kettly kettle. Radiators of various vintages, some with suspiciously cool
bottoms.

It hasn't been serviced recently (then again, these are so simple that
there isn't much to service compared to modern boilers). This also
suggests it might do with a flush and some inhibitor.

If it's not room-sealed, then it really should be checked every
year, as it can suddenly build up soot through the heat exchanger
which causes incomplete combustion and emission of carbon monoxide.

Also, in such a system, a flush and inhibitor might clear out some
scale sealing leaks, particularly in the boiler itself.

Recently knocked up a Pi-based controller for a Kingfisher cast-iron
lump, to try and improve efficiency of an old system for a friend.
That has a pumped heating circuit, but a gravity hot water cylinder
coil. It didn't have a roomstat or cylinder stat originally - it does
now, and remote control/monitoring over the Internet.

In principle I suppose you could monitor flu gas temp and turn the flame on and off frequently to keep the exchanger just above condensing, and thus get a big improvement in efficiency.


NT

In article 5828cd64$0$36793$b1db1813$ca8b28d9
@news.astraweb.com, dennis@home says...

On 13/11/2016 19:59, bert wrote:

Well if you have £4500 sitting in the bank you'll be getting about £22
pa interest. So if you invest that money in a new boiler you will be
getting a better return on your money but you have converted a liquid
asset into a depreciating fixed one.

Would there be a better return on spending that £4500 on solar panels?

Nothing wrong with upsetting TNP as long as you don't actually think it
will help save the planet.

What's the insulation like?
If it's mostly the same age as the boiler, you'd invest
much less and get bigger returns by improving that &
leaving the boiler alone.

In article ,
writes:
On Sunday, 13 November 2016 18:55:56 UTC, Andrew Gabriel wrote:
In article ,
David writes:

Brief background; visiting a friend with very old central heating -
reminds me of what was in our last house when we moved in in 1984.

An old Glow-worm 85 100 floor standing lump of iron. Kettles like a really
kettly kettle. Radiators of various vintages, some with suspiciously cool
bottoms.

It hasn't been serviced recently (then again, these are so simple that
there isn't much to service compared to modern boilers). This also
suggests it might do with a flush and some inhibitor.

If it's not room-sealed, then it really should be checked every
year, as it can suddenly build up soot through the heat exchanger
which causes incomplete combustion and emission of carbon monoxide.

Also, in such a system, a flush and inhibitor might clear out some
scale sealing leaks, particularly in the boiler itself.

Recently knocked up a Pi-based controller for a Kingfisher cast-iron
lump, to try and improve efficiency of an old system for a friend.
That has a pumped heating circuit, but a gravity hot water cylinder
coil. It didn't have a roomstat or cylinder stat originally - it does
now, and remote control/monitoring over the Internet.

In principle I suppose you could monitor flu gas temp and turn the flame on and off frequently to keep the exchanger just above condensing, and thus get a big improvement in efficiency.

Flue gas temp in a non-condensing boiler is normally 140C-200C anyway,
as the heat exchangers are nowhere near as efficient. The minimum
boiler temperature I allow to be set is 56C, although it needs to be
nearer 70C to get enough power out of the radiators to heat the house
at this time of year.

Key new features a
o Room stat.
o Setback temperature overnight.
o Frost stat protection.
o Hot water tank stat.
o Pump run-on to get back all the heat in the boiler tank when boiler
demand ceases (otherwise the stored energy just convects out the flue).
o Timeswitch settings different each day to match family requirements.
o Simple manual override with 3 buttons - toggle heating, boost heating
(switch on for an hour higher stat setting), hot water.
o All controls/monitoring available remotely over the Internet which
enables them to use them when out, and me to monitor remotely.

Also, everything is logged so I can see how the system behaves, and
I've used this data to tune system operation, e.g. how long it takes
to heat the water, and the house from any given starting point and
outside temperature.

The logging also reveals a gremlin, whereby around once a month, the
gravity circulation to the hot water cylinder coil fails to work for a
day or so, and then fixes itself. It's also interesting that it takes
10 mins or so before it kicks in anyway once the boiler is hot - I
guess until some hot water rises into the flow pipe, there is no
pressure differential to generate any flow, but when it gets started,
it picks up very quickly.

--
Andrew Gabriel
[email address is not usable -- followup in the newsgroup]

On 13/11/2016 16:32, David wrote:
Brief background; visiting a friend with very old central heating -
reminds me of what was in our last house when we moved in in 1984.

An old Glow-worm 85 100 floor standing lump of iron. Kettles like a really
kettly kettle. Radiators of various vintages, some with suspiciously cool
bottoms.

It hasn't been serviced recently (then again, these are so simple that
there isn't much to service compared to modern boilers). This also
suggests it might do with a flush and some inhibitor.

I suspect a power flush might improve the effectiveness of the radiators.

This is a large long and thin 4 bedroom bungalow with a lot of glass,
patio doors, plastic roof conservatory as part of the dining room. So
probably not that thermally efficient.

I am assuming that a new central heating system will cost more than
£4,500; possibly quite a bit more given the length of the pipe runs.

Just wondering how long it normally takes to recoup the cost of a new
highly efficient system through fuel savings.

For example, a £4,500 system would need to save £450 a year to pay back
over 10 years.

I expect the costs to be higher and the savings per year to be perhaps a
little less.

When you get past 60 long term investment looks less attractive,
especially with a pay back tome of 15-20 years.

Piece of string question but just pondering.

It all hinges on the amount being spent per year on gas and what the
boiler replacement will cost. You may be able to get a 20% saving on
fuel, but will have to work out what that is worth. You may find you get
a much bigger return for the money adding insulation instead (depending
on the current levels). Just modernising the system controls, flushing
the system, and doing a bit of rad balancing may yield a noticeable
improvement for very little cost.

In my case the boiler cost me £1200 to install, and the gas saving alone
paid for it in about three years. But, that was made far more cost
effective by DIYing the work, and having ridiculously high gas bills to
start with.


--
Cheers,

John.

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

On Sunday, 13 November 2016 22:22:46 UTC, Andrew Gabriel wrote:
In article ,
tabbypurr writes:
On Sunday, 13 November 2016 18:55:56 UTC, Andrew Gabriel wrote:
In article ,
David writes:

Brief background; visiting a friend with very old central heating -
reminds me of what was in our last house when we moved in in 1984.

An old Glow-worm 85 100 floor standing lump of iron. Kettles like a really
kettly kettle. Radiators of various vintages, some with suspiciously cool
bottoms.

It hasn't been serviced recently (then again, these are so simple that
there isn't much to service compared to modern boilers). This also
suggests it might do with a flush and some inhibitor.

If it's not room-sealed, then it really should be checked every
year, as it can suddenly build up soot through the heat exchanger
which causes incomplete combustion and emission of carbon monoxide.

Also, in such a system, a flush and inhibitor might clear out some
scale sealing leaks, particularly in the boiler itself.

Recently knocked up a Pi-based controller for a Kingfisher cast-iron
lump, to try and improve efficiency of an old system for a friend.
That has a pumped heating circuit, but a gravity hot water cylinder
coil. It didn't have a roomstat or cylinder stat originally - it does
now, and remote control/monitoring over the Internet.

In principle I suppose you could monitor flu gas temp and turn the flame on and off frequently to keep the exchanger just above condensing, and thus get a big improvement in efficiency.

Flue gas temp in a non-condensing boiler is normally 140C-200C anyway,
as the heat exchangers are nowhere near as efficient.

Flame temp is circa 2000C, so for 65% efficiency that gives exhaust gas temp over 600C. How come the figures are so different?

Even at 200C, lowering that to 120 would improve efficiency.


The minimum
boiler temperature I allow to be set is 56C, although it needs to be
nearer 70C to get enough power out of the radiators to heat the house
at this time of year.

Key new features a
o Room stat.
o Setback temperature overnight.
o Frost stat protection.
o Hot water tank stat.
o Pump run-on to get back all the heat in the boiler tank when boiler
demand ceases (otherwise the stored energy just convects out the flue).
o Timeswitch settings different each day to match family requirements.
o Simple manual override with 3 buttons - toggle heating, boost heating
(switch on for an hour higher stat setting), hot water.
o All controls/monitoring available remotely over the Internet which
enables them to use them when out, and me to monitor remotely.

Also, everything is logged so I can see how the system behaves, and
I've used this data to tune system operation, e.g. how long it takes
to heat the water, and the house from any given starting point and
outside temperature.

The logging also reveals a gremlin, whereby around once a month, the
gravity circulation to the hot water cylinder coil fails to work for a
day or so, and then fixes itself.

Slime in the primary cct? Air bubble?

It's also interesting that it takes
10 mins or so before it kicks in anyway once the boiler is hot - I
guess until some hot water rises into the flow pipe, there is no
pressure differential to generate any flow, but when it gets started,
it picks up very quickly.

I wouldn't be too surprised if cast iron boilers plus such homebrew improvement eventually turned out to be the best option long term.

In principle you could also
a) monitor flue gases & restrict input air flow to get closer to ideal mixture
b) alarm & cut out if CO levels rise
c) add a low speed stirrer to improve gas to exchanger conduction

What UK law says about a & c I don't know, I doubt they're doable.


NT

Cool bottoms, ooer missus!

Brian

--
----- -
This newsgroup posting comes to you directly from...
The Sofa of Brian Gaff...

Blind user, so no pictures please!
"David" wrote in message
...
Brief background; visiting a friend with very old central heating -
reminds me of what was in our last house when we moved in in 1984.

An old Glow-worm 85 100 floor standing lump of iron. Kettles like a really
kettly kettle. Radiators of various vintages, some with suspiciously cool
bottoms.

It hasn't been serviced recently (then again, these are so simple that
there isn't much to service compared to modern boilers). This also
suggests it might do with a flush and some inhibitor.

I suspect a power flush might improve the effectiveness of the radiators.

This is a large long and thin 4 bedroom bungalow with a lot of glass,
patio doors, plastic roof conservatory as part of the dining room. So
probably not that thermally efficient.

I am assuming that a new central heating system will cost more than
£4,500; possibly quite a bit more given the length of the pipe runs.

Just wondering how long it normally takes to recoup the cost of a new
highly efficient system through fuel savings.

For example, a £4,500 system would need to save £450 a year to pay back
over 10 years.

I expect the costs to be higher and the savings per year to be perhaps a
little less.

When you get past 60 long term investment looks less attractive,
especially with a pay back tome of 15-20 years.

Piece of string question but just pondering.

Cheers

Dave R

In article ,
writes:
On Sunday, 13 November 2016 22:22:46 UTC, Andrew Gabriel wrote:
In article ,
tabbypurr writes:
On Sunday, 13 November 2016 18:55:56 UTC, Andrew Gabriel wrote:
In article ,
David writes:

Brief background; visiting a friend with very old central heating -
reminds me of what was in our last house when we moved in in 1984.

An old Glow-worm 85 100 floor standing lump of iron. Kettles like a really
kettly kettle. Radiators of various vintages, some with suspiciously cool
bottoms.

It hasn't been serviced recently (then again, these are so simple that
there isn't much to service compared to modern boilers). This also
suggests it might do with a flush and some inhibitor.

If it's not room-sealed, then it really should be checked every
year, as it can suddenly build up soot through the heat exchanger
which causes incomplete combustion and emission of carbon monoxide.

Also, in such a system, a flush and inhibitor might clear out some
scale sealing leaks, particularly in the boiler itself.

Recently knocked up a Pi-based controller for a Kingfisher cast-iron
lump, to try and improve efficiency of an old system for a friend.
That has a pumped heating circuit, but a gravity hot water cylinder
coil. It didn't have a roomstat or cylinder stat originally - it does
now, and remote control/monitoring over the Internet.

In principle I suppose you could monitor flu gas temp and turn the flame on and off frequently to keep the exchanger just above condensing, and thus get a big improvement in efficiency.

Flue gas temp in a non-condensing boiler is normally 140C-200C anyway,
as the heat exchangers are nowhere near as efficient.

Flame temp is circa 2000C, so for 65% efficiency that gives exhaust gas temp over 600C. How come the figures are so different?

Excess air heated (you can't have no excess air as CO emission gets
too high before that point). Air paths have to be large enough not
to generate significant pressure difference, because flue isn't fanned.
That also means less contact with heat exchanger, and less heat transfer.

Also permanant pilot light - I haven't measured pilot power on this
boiler, but it's probably 300-400W 24x7 straight out the flue. This
is factored in to SEDBUK efficiency calculation. I have managed to
reduce pilot power as low as 250W in another permanent pilot device,
but that's about as low as you can get one unless it's designed for a
very tiny flame (as some town gas cookers with pilots used to be ~50
years ago, but I've never seen these in boilers).

Not recovering latent heat of water (as non-condensing).

Heat exchanger is simply nowhere near as efficient as with a modern
condensing boiler. It has nowhere near the same heat exchange surface,
thick cast iron is not a good heat conductor, and it can't be a
contra-flow design.

Could modify boiler to use an automatic pilot and main burner ignition
control board, but that gets into the realm of modifying the gas safety
parts, which is not something I would do with someone else's gas appliance.

Even at 200C, lowering that to 120 would improve efficiency.


The minimum
boiler temperature I allow to be set is 56C, although it needs to be
nearer 70C to get enough power out of the radiators to heat the house
at this time of year.

Key new features a
o Room stat.
o Setback temperature overnight.
o Frost stat protection.
o Hot water tank stat.
o Pump run-on to get back all the heat in the boiler tank when boiler
demand ceases (otherwise the stored energy just convects out the flue).
o Timeswitch settings different each day to match family requirements.
o Simple manual override with 3 buttons - toggle heating, boost heating
(switch on for an hour higher stat setting), hot water.
o All controls/monitoring available remotely over the Internet which
enables them to use them when out, and me to monitor remotely.

Also, everything is logged so I can see how the system behaves, and
I've used this data to tune system operation, e.g. how long it takes
to heat the water, and the house from any given starting point and
outside temperature.

The logging also reveals a gremlin, whereby around once a month, the
gravity circulation to the hot water cylinder coil fails to work for a
day or so, and then fixes itself.

Slime in the primary cct? Air bubble?

Probably air. There is a horizontal run under bathroom floor which
I can't see much of. Horizontal runs are not great in gravity
circuits. If this system is going to stay past this winter, I should
probably put an old central heating pump in the circuit, which would
also make heating the cylinder much faster and more efficient in summer.

It's also interesting that it takes
10 mins or so before it kicks in anyway once the boiler is hot - I
guess until some hot water rises into the flow pipe, there is no
pressure differential to generate any flow, but when it gets started,
it picks up very quickly.

I wouldn't be too surprised if cast iron boilers plus such homebrew improvement eventually turned out to be the best option long term.

In principle you could also
a) monitor flue gases & restrict input air flow to get closer to ideal mixture
b) alarm & cut out if CO levels rise
c) add a low speed stirrer to improve gas to exchanger conduction

What UK law says about a & c I don't know, I doubt they're doable.


NT

--
Andrew Gabriel
[email address is not usable -- followup in the newsgroup]

On Monday, 14 November 2016 12:16:01 UTC, Andrew Gabriel wrote:
In article ,
tabbypurr writes:
On Sunday, 13 November 2016 22:22:46 UTC, Andrew Gabriel wrote:
In article ,
tabbypurr writes:

Flue gas temp in a non-condensing boiler is normally 140C-200C anyway,
as the heat exchangers are nowhere near as efficient.

Flame temp is circa 2000C, so for 65% efficiency that gives exhaust gas temp over 600C. How come the figures are so different?

Excess air heated (you can't have no excess air as CO emission gets
too high before that point). Air paths have to be large enough not
to generate significant pressure difference, because flue isn't fanned.

To bring 600C down to 150C it would need to be passing 5x the necessary airflow through. Are they that bad?

The following are reasons for lower efficiency rather than the mismatch in flue temp figures.

That also means less contact with heat exchanger, and less heat transfer.

a stirrer could assist, in principle

Also permanant pilot light - I haven't measured pilot power on this
boiler, but it's probably 300-400W 24x7 straight out the flue. This
is factored in to SEDBUK efficiency calculation. I have managed to
reduce pilot power as low as 250W in another permanent pilot device,
but that's about as low as you can get one unless it's designed for a
very tiny flame (as some town gas cookers with pilots used to be ~50
years ago, but I've never seen these in boilers).

IIRC permanent pilots lose about 4% efficiency according to SEDBUK
If one wanted to push it that heat could be captured & used.

Not recovering latent heat of water (as non-condensing).

The 100% figure ignores the latent heat from condensing fwiw.

Heat exchanger is simply nowhere near as efficient as with a modern
condensing boiler. It has nowhere near the same heat exchange surface,
thick cast iron is not a good heat conductor, and it can't be a
contra-flow design.

Indeed. Though cast iron exchangers can be contraflow, they just weren't. The layer of rust on them can't help either.

Could modify boiler to use an automatic pilot and main burner ignition
control board, but that gets into the realm of modifying the gas safety
parts, which is not something I would do with someone else's gas appliance.

Even at 200C, lowering that to 120 would improve efficiency.

Most such tweaks are impractical, but frequent on/off to keep flue gases at 120-130C might be practical.


NT

On 13/11/2016 22:30, John Rumm wrote:

In my case the boiler cost me £1200 to install, and the gas saving alone
paid for it in about three years. But, that was made far more cost
effective by DIYing the work, and having ridiculously high gas bills to
start with.

The figures for my oil fired were not vastly different.


--
Michael Chare

---
This email has been checked for viruses by Avast antivirus software.
https://www.avast.com/antivirus

On 15/11/2016 00:09, Michael Chare wrote:
On 13/11/2016 22:30, John Rumm wrote:

In my case the boiler cost me £1200 to install, and the gas saving alone
paid for it in about three years. But, that was made far more cost
effective by DIYing the work, and having ridiculously high gas bills to
start with.

The figures for my oil fired were not vastly different.

Yup the difference between low tech gas and modern condenser is far more
pronounced than with oil.


--
Cheers,

John.

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