A while ago I asked about the possible perils of buying a listed house
(17thC timber-framed) - the survey results were so bad that I ran away
bravely. It now seems likely that I'll be buying an unlisted 1930s "arts
and crafts" style house that seems to be pretty solid (but the survey is
next week - :eeek!).
This house has a fairly old (20+ years?) Mistral oil-fired boiler, which
is certain to be non-condensing. I need to check but I think the output
is 160k BTU. My previous boiler experience has all been with gas boilers.
What do I need to know that I may not know?
What real world efficiency savings am I likely to get by changing it for
a modern, condensing, boiler?

On 18/03/2017 18:36, wrote:
A while ago I asked about the possible perils of buying a listed house
(17thC timber-framed) - the survey results were so bad that I ran away
bravely. It now seems likely that I'll be buying an unlisted 1930s "arts
and crafts" style house that seems to be pretty solid (but the survey is
next week - :eeek!).
This house has a fairly old (20+ years?) Mistral oil-fired boiler, which
is certain to be non-condensing. I need to check but I think the output
is 160k BTU. My previous boiler experience has all been with gas boilers.
What do I need to know that I may not know?
What real world efficiency savings am I likely to get by changing it for
a modern, condensing, boiler?


Is the boiler listed he

http://www.homeheatingguide.co.uk/ef...p?make=Mistral

You can also find the efficiency of new boilers.

Clearly the cost of installation will be less if DIY.

Then there there is the question of how much oil you will use, and you
have to make assumptions about the price of heating oil.

FWIW I replaced my previous boiler with a new more efficient but non
condensing one. I am sure that the boiler has paid for itself.


--
Michael Chare

---
This email has been checked for viruses by Avast antivirus software.
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On 18/03/2017 19:00, Chris Hogg wrote:
On Sat, 18 Mar 2017 18:36:51 +0000, wrote:


Do they make condensing oil-fired boilers now? AIUI they used not to,
as the benefits in terms of improve efficiency were marginal (oil,
having a composition with less hydrogen and more carbon than gas, per
molecule or per unit weight, doesn't generate as much water vapour
when burnt, so the energy to be recovered by condensing that vapour is
less).


I suspect you would find it difficult to buy a domestic non condensing
oil boiler. Are you aware of any?


--
Michael Chare

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

On 3/18/2017 3:00 PM, Chris Hogg wrote:

Do they make condensing oil-fired boilers now? AIUI they used not to,
as the benefits in terms of improve efficiency were marginal (oil,
having a composition with less hydrogen and more carbon than gas, per
molecule or per unit weight, doesn't generate as much water vapour
when burnt, so the energy to be recovered by condensing that vapour is
less).

Yes, they do. We've had a Grant condensing oil-fired boiler for a few
years now, and are very pleased with it. I don't have the figures to
hand, but our oil usage has dropped considerably.

But there may be other benefits in a new boiler, especially if you
have mains gas available and install a condensing gas boiler. If no
mains gas, you could always install an LPG boiler but that would mean
a gas tank in the garden and an expensive gas supply relative to mains
gas.

Chris Hogg wrote:

Michael Chare wrote:

I suspect you would find it difficult to buy a domestic non condensing
oil boiler. Are you aware of any?

Mistral make both apparently, https://www.mistralboilers.com/ but the
situation has obviously changed since I formed the opinion expressed
above. According to WHICH*, "Typically, a new condensing oil-fired
boiler will have an efficiency of 92% to 93%, compared with 85% for a
new non-condensing boiler and 60% to 70% for older systems."

To be allowed to fit a domestic non-condensing boiler, you must pass an
assessment procedure ...

http://www.planningportal.gov.uk/uploads/br/BR_PDF_PTL_CONDBOILER.pdf

"Michael Chare" wrote in message
news
On 18/03/2017 19:00, Chris Hogg wrote:
On Sat, 18 Mar 2017 18:36:51 +0000, wrote:


Do they make condensing oil-fired boilers now? AIUI they used not to,
as the benefits in terms of improve efficiency were marginal (oil,
having a composition with less hydrogen and more carbon than gas, per
molecule or per unit weight, doesn't generate as much water vapour
when burnt, so the energy to be recovered by condensing that vapour is
less).


I suspect you would find it difficult to buy a domestic non condensing oil
boiler. Are you aware of any?

When we replaced our old Grant oil boiler with a new one (old one's heat
exchanger rusted through) we were told that Grant no longer made a
non-condensing one in the size that we needed. We've been pleased with the
new boiler, though we get more "singing" from the radiators as the
water-plus-Fernox is circulating - and that's with the pump turned to
minimum speed. The increase in noise may be more due to the addition of
Fernox (which may have loosened/dissolved deposits) than the change of
boiler. The boiler itself is quieter (less of a thump when the burner
initially lights up).

This is for an outside boiler, rather than a wall-mounted or under-worktop
one in the kitchen etc.

On 18/03/17 18:36, wrote:
A while ago I asked about the possible perils of buying a listed house
(17thC timber-framed) - the survey results were so bad that I ran away
bravely. It now seems likely that I'll be buying an unlisted 1930s "arts
and crafts" style house that seems to be pretty solid (but the survey is
next week - :eeek!).
This house has a fairly old (20+ years?) Mistral oil-fired boiler, which
is certain to be non-condensing. I need to check but I think the output
is 160k BTU. My previous boiler experience has all been with gas boilers.
What do I need to know that I may not know?
What real world efficiency savings am I likely to get by changing it for
a modern, condensing, boiler?


I moved last year. The oil-fired boiler here is 30 years old, regularly
maintained by the same local man since installed. Parts are still
available it may last a few years yet, whereas a new boiler may not last
more than 10. It may only be 70% efficient but a new 95% efficient one
is unlikely to shave more than £150 pa off my oil bill. So I plan to
keep it until it breaks.


--
djc

(–€Ì¿Ä¹Ì¯–€Ì¿ Ì¿)
No low-hanging fruit, just a lot of small berries up a tall tree.

On 18/03/2017 18:36, wrote:
A while ago I asked about the possible perils of buying a listed house
(17thC timber-framed) - the survey results were so bad that I ran away
bravely. It now seems likely that I'll be buying an unlisted 1930s "arts
and crafts" style house that seems to be pretty solid (but the survey is
next week - :eeek!).
This house has a fairly old (20+ years?) Mistral oil-fired boiler, which
is certain to be non-condensing. I need to check but I think the output
is 160k BTU. My previous boiler experience has all been with gas boilers.
What do I need to know that I may not know?
What real world efficiency savings am I likely to get by changing it for
a modern, condensing, boiler?

After a bit of googling I think I can answer my own question. An
efficiency improvement of 25% on 2000 litres/year (no idea whether
that's correct) at 41p/litre is about £205, so that pays back at 15
years. If that's correct, and unless there are any grants, it's worth
keeping the old boiler going for as long as reasonably possible.

On Sunday, 19 March 2017 00:09:43 UTC, wrote:
On 18/03/2017 18:36, wrote:

A while ago I asked about the possible perils of buying a listed house
(17thC timber-framed) - the survey results were so bad that I ran away
bravely. It now seems likely that I'll be buying an unlisted 1930s "arts
and crafts" style house that seems to be pretty solid (but the survey is
next week - :eeek!).
This house has a fairly old (20+ years?) Mistral oil-fired boiler, which
is certain to be non-condensing. I need to check but I think the output
is 160k BTU. My previous boiler experience has all been with gas boilers.
What do I need to know that I may not know?
What real world efficiency savings am I likely to get by changing it for
a modern, condensing, boiler?

After a bit of googling I think I can answer my own question. An
efficiency improvement of 25% on 2000 litres/year (no idea whether
that's correct) at 41p/litre is about £205, so that pays back at 15
years. If that's correct, and unless there are any grants, it's worth
keeping the old boiler going for as long as reasonably possible.

It always struck me that one could improve the efficiency of old boilers by just turning down the gas or oil feed some, checking the exhaust stays at at least 120C so it doesn't condense (which would rot the exchanger). But I don't think such things are allowed.

On 19/03/2017 00:09, wrote:
On 18/03/2017 18:36, wrote:
A while ago I asked about the possible perils of buying a listed house
(17thC timber-framed) - the survey results were so bad that I ran away
bravely. It now seems likely that I'll be buying an unlisted 1930s "arts
and crafts" style house that seems to be pretty solid (but the survey is
next week - :eeek!).
This house has a fairly old (20+ years?) Mistral oil-fired boiler, which
is certain to be non-condensing. I need to check but I think the output
is 160k BTU. My previous boiler experience has all been with gas boilers.
What do I need to know that I may not know?
What real world efficiency savings am I likely to get by changing it for
a modern, condensing, boiler?

After a bit of googling I think I can answer my own question. An
efficiency improvement of 25% on 2000 litres/year (no idea whether
that's correct) at 41p/litre is about £205, so that pays back at 15
years.

£3k for a boiler? Sounds a bit steep, or was that including commercial
fitting as well?




--
Cheers,

John.

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

On Saturday, 18 March 2017 18:36:49 UTC, wrote:
A while ago I asked about the possible perils of buying a listed house
(17thC timber-framed) - the survey results were so bad that I ran away
bravely. It now seems likely that I'll be buying an unlisted 1930s "arts
and crafts" style house that seems to be pretty solid (but the survey is
next week - :eeek!).
This house has a fairly old (20+ years?) Mistral oil-fired boiler, which
is certain to be non-condensing. I need to check but I think the output
is 160k BTU. My previous boiler experience has all been with gas boilers.
What do I need to know that I may not know?
What real world efficiency savings am I likely to get by changing it for
a modern, condensing, boiler?

You need to check the oil tank as well.
See if there is water in the bottom (there's usually a drain tap ofr this purpose).
If it's a Steel tank there may be corrosion.

On 19/03/17 01:30, wrote:


It always struck me that one could improve the efficiency of old
boilers by just turning down the gas or oil feed some, checking the
exhaust stays at at least 120C so it doesn't condense (which would
rot the exchanger). But I don't think such things are allowed.

?

How can increasing the exhaust gas temperature increase efficiency?
Surely that is just more heat wasted up the flue. It might prevent
condensation, but at the expense of reducing efficiency.

--

Jeff

On 18/03/17 18:36, wrote:
What real world efficiency savings am I likely to get by changing it for
a modern, condensing, boiler?
Not nearly as much as getting the insulation sorted.

Boiler should be the last thing you tackle.

--
If I had all the money I've spent on drink...
...I'd spend it on drink.

Sir Henry (at Rawlinson's End)

On 19/03/17 00:09, wrote:
After a bit of googling I think I can answer my own question. An
efficiency improvement of 25% on 2000 litres/year (no idea whether
that's correct) at 41p/litre is about £205, so that pays back at 15
years. If that's correct, and unless there are any grants, it's worth
keeping the old boiler going for as long as reasonably possible.

Echos my sentiments.

If its a non insulated house you can double the oil consumption tho.


--
If I had all the money I've spent on drink...
...I'd spend it on drink.

Sir Henry (at Rawlinson's End)

On Sunday, 19 March 2017 08:22:41 UTC, Jeff Layman wrote:
On 19/03/17 01:30, tabbypurr wrote:


It always struck me that one could improve the efficiency of old
boilers by just turning down the gas or oil feed some, checking the
exhaust stays at at least 120C so it doesn't condense (which would
rot the exchanger). But I don't think such things are allowed.

?

How can increasing the exhaust gas temperature increase efficiency?
Surely that is just more heat wasted up the flue. It might prevent
condensation, but at the expense of reducing efficiency.

you misread, I said pretty much the opposite


NT

On 19/03/2017 02:28, John Rumm wrote:
On 19/03/2017 00:09, wrote:
On 18/03/2017 18:36, wrote:
A while ago I asked about the possible perils of buying a listed house
(17thC timber-framed) - the survey results were so bad that I ran away
bravely. It now seems likely that I'll be buying an unlisted 1930s "arts
and crafts" style house that seems to be pretty solid (but the survey is
next week - :eeek!).
This house has a fairly old (20+ years?) Mistral oil-fired boiler, which
is certain to be non-condensing. I need to check but I think the output
is 160k BTU. My previous boiler experience has all been with gas
boilers.
What do I need to know that I may not know?
What real world efficiency savings am I likely to get by changing it for
a modern, condensing, boiler?

After a bit of googling I think I can answer my own question. An
efficiency improvement of 25% on 2000 litres/year (no idea whether
that's correct) at 41p/litre is about £205, so that pays back at 15
years.

£3k for a boiler? Sounds a bit steep, or was that including commercial
fitting as well?

It was only a SWAG based on: a boiler cost of around £2200, labour
needed (these boilers are surprisingly heavy - around 270kg!) and
replacing some pipework at the same time.
Because immediate boiler replacement isn't obviously worthwhile I think
we'll plan to live there and see what the actual oil consumption is.
There are two wood burners (and I plan to open-up a third, currently
closed) fireplace so their use is going to make a big difference to oil
demand.

(In case you don't know, SWAG is Scientific Wild-Arsed Guess. I've
always liked the term and have used it most of my professional life ;-) )

On 19/03/2017 08:31, The Natural Philosopher wrote:
On 18/03/17 18:36, wrote:
What real world efficiency savings am I likely to get by changing it for
a modern, condensing, boiler?
Not nearly as much as getting the insulation sorted.

Boiler should be the last thing you tackle.

The window frames are steel, mostly single-glazed but some have been
double-glazed. One of the early tasks will be tidying-up the windows and
looking for ways to fit (thin) double glazing panels to them - expect
another thread on this once we've moved-in!

Apart from windows and doors I don't think there's much scope to improve
the insulation, but I'll certainly be investigating what can be done.
The construction appears to be rendered concrete block but I don't know
yet whether there's a cavity. The loft is large (purlins, so no
obstructions), high, fully boarded and with boards on the outside of the
rafters (Sarking boards?). Lifting the floorboards would be a helluva
job and adding decent insulation between the rafters would be very
expensive.

On 18/03/2017 18:36, wrote:
A while ago I asked about the possible perils of buying a listed house
(17thC timber-framed) - the survey results were so bad that I ran away
bravely. It now seems likely that I'll be buying an unlisted 1930s "arts
and crafts" style house that seems to be pretty solid (but the survey is
next week - :eeek!).
This house has a fairly old (20+ years?) Mistral oil-fired boiler, which
is certain to be non-condensing. I need to check but I think the output
is 160k BTU. My previous boiler experience has all been with gas boilers.
What do I need to know that I may not know?
What real world efficiency savings am I likely to get by changing it for
a modern, condensing, boiler?

Personally I would run the system as is for a year to see if it is
adequate and if any other improvements in insulation etc could reduce
the size of boiler required.

Many years ago a 160k BTU boiler would have been a commercial boiler and
it was then cheaper to purchase 2 separate domestic boilers and run in
parallel using non-return valves to prevent unwanted water flows.

That might still be the case, although you would then need 2 flues.

On 19/03/2017 08:33, The Natural Philosopher wrote:
On 19/03/17 00:09, wrote:
After a bit of googling I think I can answer my own question. An
efficiency improvement of 25% on 2000 litres/year (no idea whether
that's correct) at 41p/litre is about £205, so that pays back at 15
years. If that's correct, and unless there are any grants, it's worth
keeping the old boiler going for as long as reasonably possible.

Echos my sentiments.

If its a non insulated house you can double the oil consumption tho.


Yes, it's just dawned on me that 4000 litres might be closer - that
would make a boiler replacement much more sensible. I need to wait for
real usage data.

On 19/03/2017 10:12, Fredxxx wrote:
On 18/03/2017 18:36, wrote:
A while ago I asked about the possible perils of buying a listed house
(17thC timber-framed) - the survey results were so bad that I ran away
bravely. It now seems likely that I'll be buying an unlisted 1930s "arts
and crafts" style house that seems to be pretty solid (but the survey is
next week - :eeek!).
This house has a fairly old (20+ years?) Mistral oil-fired boiler, which
is certain to be non-condensing. I need to check but I think the output
is 160k BTU. My previous boiler experience has all been with gas boilers.
What do I need to know that I may not know?
What real world efficiency savings am I likely to get by changing it for
a modern, condensing, boiler?

Personally I would run the system as is for a year to see if it is
adequate and if any other improvements in insulation etc could reduce
the size of boiler required.

Many years ago a 160k BTU boiler would have been a commercial boiler and
it was then cheaper to purchase 2 separate domestic boilers and run in
parallel using non-return valves to prevent unwanted water flows.

That might still be the case, although you would then need 2 flues.

During the discussion I've moved to the same point of view - wait and
see because the break-even is so heavily influenced by the actual oil
consumption. Blindingly obvious with hindsight but it's been useful to
have the discussion.

It would not be cheaper to install two boilers in parallel these days,
even leaving out the maintenance and increased failure risk.
Brings to mind the explanation for why Lindbergh chose a single-engined
aircraft: with a twin there was twice the chance of engine failure and
the remaining engine would not be capable of completing the task.

On 18/03/2017 20:02, Michael Chare wrote:
On 18/03/2017 18:36, wrote:
A while ago I asked about the possible perils of buying a listed house
(17thC timber-framed) - the survey results were so bad that I ran away
bravely. It now seems likely that I'll be buying an unlisted 1930s "arts
and crafts" style house that seems to be pretty solid (but the survey is
next week - :eeek!).
This house has a fairly old (20+ years?) Mistral oil-fired boiler, which
is certain to be non-condensing. I need to check but I think the output
is 160k BTU. My previous boiler experience has all been with gas boilers.
What do I need to know that I may not know?
What real world efficiency savings am I likely to get by changing it for
a modern, condensing, boiler?


Is the boiler listed he

http://www.homeheatingguide.co.uk/ef...p?make=Mistral

You can also find the efficiency of new boilers.

Clearly the cost of installation will be less if DIY.

Then there there is the question of how much oil you will use, and you
have to make assumptions about the price of heating oil.

FWIW I replaced my previous boiler with a new more efficient but non
condensing one. I am sure that the boiler has paid for itself.



That's an interesting link; I'll make a note of the model number when
I'm next there.

On Sun, 19 Mar 2017 09:53:26 +0000, wrote:

This house has a fairly old (20+ years?) Mistral oil-fired
boiler,
which is certain to be non-condensing. I need to check but I
think
the output is 160k BTU.

Wozzat in kW? google 45 ish, thats rather big. How big is the
house? We have a similar vintage and size Mistral oil boiler but it's
heating more or less the volume of 2 three bed semis.

What do I need to know that I may not know?

If it's like ours its a gert lump of cast iron that hold 12 gallons
of water with a baffle plates up the central hollow hole in the top
for the flue, hole in the bottom for the burner. They are supposed to
have a clean out, jet, oil, filter and flexable oil hose(s) changed
and electrodes adjusted every year. But they are so bog simple they
generally "just work".

What real world efficiency savings am I likely to get by
changing it
for a modern, condensing, boiler?

Probably not a lot. Every time ours has been serviced the flue gas
temperature indicates an 80% effciency, that does tend to be not long
after it's been fired up from cold though.

After a bit of googling I think I can answer my own question. An
efficiency improvement of 25% on 2000 litres/year (no idea
whether
that's correct) at 41p/litre is about £205, so that pays back at
15
years.

I don't think you'll see a 25% improvement, that implies 65% or lower
now. We used to get through 4,000 l/year but improving insulation,
removing gale force draughts adding a 11 kW wood burner (7 kW to
water) has knocked that back to 3000 ish. Bear in mind this is a
large, high and exposed property.

Because immediate boiler replacement isn't obviously worthwhile I think
we'll plan to live there and see what the actual oil consumption is.

You could ask the sellers how much oil they get through as a rough
guide. That does make assumptions about life style, how hot/cold they
have the place and how good the control system is. When we moved in
here the heating thermostat was in one of the coldest rooms and
didn't have a radiator in it!

(In case you don't know, SWAG is Scientific Wild-Arsed Guess.

I might borrow that. B-) It's easier to type than guesstimation.

--
Cheers
Dave.

On 19/03/17 10:21, wrote:
On 19/03/2017 08:33, The Natural Philosopher wrote:
On 19/03/17 00:09, wrote:
After a bit of googling I think I can answer my own question. An
efficiency improvement of 25% on 2000 litres/year (no idea whether
that's correct) at 41p/litre is about £205, so that pays back at 15
years. If that's correct, and unless there are any grants, it's worth
keeping the old boiler going for as long as reasonably possible.

Echos my sentiments.

If its a non insulated house you can double the oil consumption tho.


Yes, it's just dawned on me that 4000 litres might be closer - that
would make a boiler replacement much more sensible.

No, it would make insulating te4 house a lot mopre sensible.

You want halve your oil with a new boiler but you might with wall
insulation and DG

I need to wait for
real usage data.

You need to work out the insulation quality of the house with a suitable
insulation calculator.


--
"I am inclined to tell the truth and dislike people who lie consistently.
This makes me unfit for the company of people of a Left persuasion, and
all women"

wrote:
On 18/03/2017 18:36, wrote:
A while ago I asked about the possible perils of buying a listed house
(17thC timber-framed) - the survey results were so bad that I ran away
bravely. It now seems likely that I'll be buying an unlisted 1930s "arts
and crafts" style house that seems to be pretty solid (but the survey is
next week - :eeek!).
This house has a fairly old (20+ years?) Mistral oil-fired boiler, which
is certain to be non-condensing. I need to check but I think the output
is 160k BTU. My previous boiler experience has all been with gas boilers.
What do I need to know that I may not know?
What real world efficiency savings am I likely to get by changing it for
a modern, condensing, boiler?

After a bit of googling I think I can answer my own question. An
efficiency improvement of 25% on 2000 litres/year (no idea whether
that's correct) at 41p/litre is about £205, so that pays back at 15
years. If that's correct, and unless there are any grants, it's worth
keeping the old boiler going for as long as reasonably possible.
Also to reinforce your decision, retro fitting a condensing boiler to
existing rads is not likely to achieve the stated efficiency. To get
even near the published figures, the flow/return temps have to be lower
and so the heat output from the rads will fall.
You will have to up the flow temp and sacrifice efficiency or fit new
bigger rads and allow for that in your capital outlay.

wrote in message ...
The loft is large (purlins, so no obstructions), high, fully boarded and
with boards on the outside of the rafters (Sarking boards?). Lifting the
floorboards would be a helluva job and adding decent insulation between
the rafters would be very expensive.

If you even *can* lift the floorboards.

When a rat died in our loft I investigated how to lift the large MDF boards
that the previous owner had fitted, in order to be able to locate it. I
undid all the screws securing on a board, as a trial. I chose a board at a
corner so if there was any tongue and grooving, the board would slide out.

But the board wouldn't move. Not even slightly. There were no nail heads
visible, so I can only assume that the stupid insert expletive who had
boarded the loft had glued the boards to the rafters as well as screwing
them down :-(

Fortunately I found that the rat had considerately died just within arm's
length under one of the boards that was open to the side near the eaves, so
I was able to reach in with a plastic bag on my hand and remove the very
smelly corpse.

It still took a few days for the lingering aroma to dissipate.

On 19/03/2017 02:28, John Rumm wrote:
On 19/03/2017 00:09, nospam@thl boanks.com wrote:
On 18/03/2017 18:36, wrote:
A while ago I asked about the possible perils of buying a listed house
(17thC timber-framed) - the survey results were so bad that I ran away
bravely. It now seems likely that I'll be buying an unlisted 1930s "arts
and crafts" style house that seems to be pretty solid (but the survey is
next week - :eeek!).
This house has a fairly old (20+ years?) Mistral oil-fired boiler, which
is certain to be non-condensing. I need to check but I think the output
is 160k BTU. My previous boiler experience has all been with gas
boilers.
What do I need to know that I may not know?
What real world efficiency savings am I likely to get by changing it for
a modern, condensing, boiler?

After a bit of googling I think I can answer my own question. An
efficiency improvement of 25% on 2000 litres/year (no idea whether
that's correct) at 41p/litre is about £205, so that pays back at 15
years.

£3k for a boiler? Sounds a bit steep, or was that including commercial
fitting as well?




That price sounds a tad low to me. l was qouted over £5k by more than
one source for a new 65k BTU oil boiler fully installed, not
surprisingly l kept my old one.

On 19/03/2017 11:58, Bob Minchin wrote:
wrote:
On 18/03/2017 18:36, wrote:
A while ago I asked about the possible perils of buying a listed house
(17thC timber-framed) - the survey results were so bad that I ran away
bravely. It now seems likely that I'll be buying an unlisted 1930s "arts
and crafts" style house that seems to be pretty solid (but the survey is
next week - :eeek!).
This house has a fairly old (20+ years?) Mistral oil-fired boiler, which
is certain to be non-condensing. I need to check but I think the output
is 160k BTU. My previous boiler experience has all been with gas
boilers.
What do I need to know that I may not know?
What real world efficiency savings am I likely to get by changing it for
a modern, condensing, boiler?

After a bit of googling I think I can answer my own question. An
efficiency improvement of 25% on 2000 litres/year (no idea whether
that's correct) at 41p/litre is about £205, so that pays back at 15
years. If that's correct, and unless there are any grants, it's worth
keeping the old boiler going for as long as reasonably possible.
Also to reinforce your decision, retro fitting a condensing boiler to
existing rads is not likely to achieve the stated efficiency. To get
even near the published figures, the flow/return temps have to be lower
and so the heat output from the rads will fall.
You will have to up the flow temp and sacrifice efficiency or fit new
bigger rads and allow for that in your capital outlay.

Thanks, that's something I hadn't considered.

On 19/03/17 09:36, wrote:
On Sunday, 19 March 2017 08:22:41 UTC, Jeff Layman wrote:
On 19/03/17 01:30, tabbypurr wrote:


It always struck me that one could improve the efficiency of old
boilers by just turning down the gas or oil feed some, checking the
exhaust stays at at least 120C so it doesn't condense (which would
rot the exchanger). But I don't think such things are allowed.

?

How can increasing the exhaust gas temperature increase efficiency?
Surely that is just more heat wasted up the flue. It might prevent
condensation, but at the expense of reducing efficiency.

you misread, I said pretty much the opposite


NT

Agreed. I saw 2 + 2 = 5 (I should be in politics...)

--

Jeff

On Sunday, 19 March 2017 10:04:44 UTC, wrote:
On 19/03/2017 08:31, The Natural Philosopher wrote:
On 18/03/17 18:36, wrote:
What real world efficiency savings am I likely to get by changing it for
a modern, condensing, boiler?
Not nearly as much as getting the insulation sorted.

Boiler should be the last thing you tackle.

The window frames are steel, mostly single-glazed but some have been
double-glazed. One of the early tasks will be tidying-up the windows and
looking for ways to fit (thin) double glazing panels to them - expect
another thread on this once we've moved-in!

Crittall windows are a disaster as far as energy loss goes. Secondary glaze them all, or contemplate replacement. DG on Crittalls won't solve it - not that I've ever seen that done, or are sure how it would be.


Apart from windows and doors I don't think there's much scope to improve
the insulation, but I'll certainly be investigating what can be done.
The construction appears to be rendered concrete block but I don't know
yet whether there's a cavity. The loft is large (purlins, so no
obstructions), high, fully boarded and with boards on the outside of the
rafters (Sarking boards?). Lifting the floorboards would be a helluva
job

but blowing polystyrene beads or cellulose in isn't.

and adding decent insulation between the rafters would be very
expensive.


NT

On Sunday, 19 March 2017 10:36:18 UTC, wrote:
On 19/03/2017 10:12, Fredxxx wrote:
On 18/03/2017 18:36, wrote:
A while ago I asked about the possible perils of buying a listed house
(17thC timber-framed) - the survey results were so bad that I ran away
bravely. It now seems likely that I'll be buying an unlisted 1930s "arts
and crafts" style house that seems to be pretty solid (but the survey is
next week - :eeek!).
This house has a fairly old (20+ years?) Mistral oil-fired boiler, which
is certain to be non-condensing. I need to check but I think the output
is 160k BTU. My previous boiler experience has all been with gas boilers.
What do I need to know that I may not know?
What real world efficiency savings am I likely to get by changing it for
a modern, condensing, boiler?

Personally I would run the system as is for a year to see if it is
adequate and if any other improvements in insulation etc could reduce
the size of boiler required.

Many years ago a 160k BTU boiler would have been a commercial boiler and
it was then cheaper to purchase 2 separate domestic boilers and run in
parallel using non-return valves to prevent unwanted water flows.

That might still be the case, although you would then need 2 flues.

During the discussion I've moved to the same point of view - wait and
see because the break-even is so heavily influenced by the actual oil
consumption. Blindingly obvious with hindsight but it's been useful to
have the discussion.

It would not be cheaper to install two boilers in parallel these days,
even leaving out the maintenance and increased failure risk.

You've not looked on ebay then.

Brings to mind the explanation for why Lindbergh chose a single-engined
aircraft: with a twin there was twice the chance of engine failure and
the remaining engine would not be capable of completing the task.

But the opposite applies with boilers, one running shifts the situation from urgent to not.


NT

On Sunday, 19 March 2017 09:53:24 UTC, wrote:
On 19/03/2017 02:28, John Rumm wrote:
On 19/03/2017 00:09, wrote:
On 18/03/2017 18:36, wrote:
A while ago I asked about the possible perils of buying a listed house
(17thC timber-framed) - the survey results were so bad that I ran away
bravely. It now seems likely that I'll be buying an unlisted 1930s "arts
and crafts" style house that seems to be pretty solid (but the survey is
next week - :eeek!).
This house has a fairly old (20+ years?) Mistral oil-fired boiler, which
is certain to be non-condensing. I need to check but I think the output
is 160k BTU. My previous boiler experience has all been with gas
boilers.
What do I need to know that I may not know?
What real world efficiency savings am I likely to get by changing it for
a modern, condensing, boiler?

After a bit of googling I think I can answer my own question. An
efficiency improvement of 25% on 2000 litres/year (no idea whether
that's correct) at 41p/litre is about £205, so that pays back at 15
years.

£3k for a boiler? Sounds a bit steep, or was that including commercial
fitting as well?

It was only a SWAG based on: a boiler cost of around £2200, labour
needed (these boilers are surprisingly heavy - around 270kg!) and
replacing some pipework at the same time.
Because immediate boiler replacement isn't obviously worthwhile I think
we'll plan to live there and see what the actual oil consumption is.
There are two wood burners (and I plan to open-up a third, currently
closed) fireplace so their use is going to make a big difference to oil
demand.

(In case you don't know, SWAG is Scientific Wild-Arsed Guess. I've
always liked the term and have used it most of my professional life ;-) )

If you buy a wood burning stove, be sure to get a room sealed one. Far more effective.

http://www.stovesonline.co.uk/external-air-stove.html

On Sunday, 19 March 2017 11:58:46 UTC, Bob Minchin wrote:
wrote:
On 18/03/2017 18:36, wrote:
A while ago I asked about the possible perils of buying a listed house
(17thC timber-framed) - the survey results were so bad that I ran away
bravely. It now seems likely that I'll be buying an unlisted 1930s "arts
and crafts" style house that seems to be pretty solid (but the survey is
next week - :eeek!).
This house has a fairly old (20+ years?) Mistral oil-fired boiler, which
is certain to be non-condensing. I need to check but I think the output
is 160k BTU. My previous boiler experience has all been with gas boilers.
What do I need to know that I may not know?
What real world efficiency savings am I likely to get by changing it for
a modern, condensing, boiler?

After a bit of googling I think I can answer my own question. An
efficiency improvement of 25% on 2000 litres/year (no idea whether
that's correct) at 41p/litre is about £205, so that pays back at 15
years. If that's correct, and unless there are any grants, it's worth
keeping the old boiler going for as long as reasonably possible.
Also to reinforce your decision, retro fitting a condensing boiler to
existing rads is not likely to achieve the stated efficiency. To get
even near the published figures, the flow/return temps have to be lower
and so the heat output from the rads will fall.
You will have to up the flow temp and sacrifice efficiency or fit new
bigger rads and allow for that in your capital outlay.

Another reason to insulate.
The rads will then still be big enough.

On Sunday, 19 March 2017 10:04:44 UTC, wrote:
On 19/03/2017 08:31, The Natural Philosopher wrote:
On 18/03/17 18:36, wrote:
What real world efficiency savings am I likely to get by changing it for
a modern, condensing, boiler?
Not nearly as much as getting the insulation sorted.

Boiler should be the last thing you tackle.

The window frames are steel, mostly single-glazed but some have been
double-glazed. One of the early tasks will be tidying-up the windows and
looking for ways to fit (thin) double glazing panels to them - expect
another thread on this once we've moved-in!

Apart from windows and doors I don't think there's much scope to improve
the insulation, but I'll certainly be investigating what can be done.
The construction appears to be rendered concrete block but I don't know
yet whether there's a cavity. The loft is large (purlins, so no
obstructions), high, fully boarded and with boards on the outside of the
rafters (Sarking boards?). Lifting the floorboards would be a helluva
job and adding decent insulation between the rafters would be very
expensive.

Roof insulation is vital.
Lifting floorboards is minor.
Just don't go piling a lot of stuff up there.
Also foam/fibres can be blown in.

There are grants. Might even be free.
Check with you energy provider.

On Sun, 19 Mar 2017 00:09:44 +0000, nospam wrote:

On 18/03/2017 18:36, wrote:
A while ago I asked about the possible perils of buying a listed house
(17thC timber-framed) - the survey results were so bad that I ran away
bravely. It now seems likely that I'll be buying an unlisted 1930s
"arts and crafts" style house that seems to be pretty solid (but the
survey is next week - :eeek!).
This house has a fairly old (20+ years?) Mistral oil-fired boiler,
which is certain to be non-condensing. I need to check but I think the
output is 160k BTU. My previous boiler experience has all been with gas
boilers.
What do I need to know that I may not know?
What real world efficiency savings am I likely to get by changing it
for a modern, condensing, boiler?

After a bit of googling I think I can answer my own question. An
efficiency improvement of 25% on 2000 litres/year (no idea whether
that's correct) at 41p/litre is about £205, so that pays back at 15
years. If that's correct, and unless there are any grants, it's worth
keeping the old boiler going for as long as reasonably possible.

It's the absence of such ROI reasoning that allowed the billions of
pounds to be frittered away on solar farms and wind turbines by the
government fulfilling the manifesto promises made purely to win votes
away from the Green Party here in the UK. I guess even the most basic
"Back of a pack of ciggies" long term investment costs analysis were too
much of an "Inconvenient Truth" to be raised as the entirely reasonable
objection to implementing such projects beyond the level of small scale
proof of concept.

--
Johnny B Good

On 19/03/17 10:04, wrote:
On 19/03/2017 08:31, The Natural Philosopher wrote:
On 18/03/17 18:36, wrote:
What real world efficiency savings am I likely to get by changing it for
a modern, condensing, boiler?
Not nearly as much as getting the insulation sorted.

Boiler should be the last thing you tackle.

The window frames are steel, mostly single-glazed but some have been
double-glazed. One of the early tasks will be tidying-up the windows and
looking for ways to fit (thin) double glazing panels to them - expect
another thread on this once we've moved-in!

Apart from windows and doors I don't think there's much scope to improve
the insulation, but I'll certainly be investigating what can be done.
The construction appears to be rendered concrete block but I don't know
yet whether there's a cavity.


If it was built since 1920s it will have a cavity as that was when it
became requirement everywhere. Cavity walls have been used since 1870s
in some areas. ie my house was built before 1900 and has a cavity.



The loft is large (purlins, so no
obstructions), high, fully boarded and with boards on the outside of the
rafters (Sarking boards?). Lifting the floorboards would be a helluva
job and adding decent insulation between the rafters would be very
expensive.


--
djc

(–€Ì¿Ä¹Ì¯–€Ì¿ Ì¿)
No low-hanging fruit, just a lot of small berries up a tall tree.

On 19/03/17 20:19, DJC wrote:
On 19/03/17 10:04, wrote:
On 19/03/2017 08:31, The Natural Philosopher wrote:
On 18/03/17 18:36, wrote:
What real world efficiency savings am I likely to get by changing it
for
a modern, condensing, boiler?
Not nearly as much as getting the insulation sorted.

Boiler should be the last thing you tackle.

The window frames are steel, mostly single-glazed but some have been
double-glazed. One of the early tasks will be tidying-up the windows and
looking for ways to fit (thin) double glazing panels to them - expect
another thread on this once we've moved-in!

Apart from windows and doors I don't think there's much scope to improve
the insulation, but I'll certainly be investigating what can be done.
The construction appears to be rendered concrete block but I don't know
yet whether there's a cavity.


If it was built since 1920s it will have a cavity as that was when it
became requirement everywhere. Cavity walls have been used since 1870s
in some areas. ie my house was built before 1900 and has a cavity.

I dont think cavity walls became a requirement until the 50s or 60-s.

Lots of solid brick 1930s stuff




--
€œIt is hard to imagine a more stupid decision or more dangerous way of
making decisions than by putting those decisions in the hands of people
who pay no price for being wrong.€�

Thomas Sowell

On 19/03/2017 21:16, The Natural Philosopher wrote:
On 19/03/17 20:19, DJC wrote:
On 19/03/17 10:04, wrote:
On 19/03/2017 08:31, The Natural Philosopher wrote:
On 18/03/17 18:36, wrote:
What real world efficiency savings am I likely to get by changing it
for
a modern, condensing, boiler?
Not nearly as much as getting the insulation sorted.

Boiler should be the last thing you tackle.

The window frames are steel, mostly single-glazed but some have been
double-glazed. One of the early tasks will be tidying-up the windows and
looking for ways to fit (thin) double glazing panels to them - expect
another thread on this once we've moved-in!

Apart from windows and doors I don't think there's much scope to improve
the insulation, but I'll certainly be investigating what can be done.
The construction appears to be rendered concrete block but I don't know
yet whether there's a cavity.


If it was built since 1920s it will have a cavity as that was when it
became requirement everywhere. Cavity walls have been used since 1870s
in some areas. ie my house was built before 1900 and has a cavity.

I dont think cavity walls became a requirement until the 50s or 60-s.

Lots of solid brick 1930s stuff

My house was built in the mid fifties, the bottom half is cavity, the
top half is tile hung block.

--
Michael Chare

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

On 19/03/2017 13:36, wrote:
On 19/03/2017 11:58, Bob Minchin wrote:
wrote:
On 18/03/2017 18:36, wrote:
A while ago I asked about the possible perils of buying a listed house
(17thC timber-framed) - the survey results were so bad that I ran away
bravely. It now seems likely that I'll be buying an unlisted 1930s
"arts
and crafts" style house that seems to be pretty solid (but the
survey is
next week - :eeek!).
This house has a fairly old (20+ years?) Mistral oil-fired boiler,
which
is certain to be non-condensing. I need to check but I think the output
is 160k BTU. My previous boiler experience has all been with gas
boilers.
What do I need to know that I may not know?
What real world efficiency savings am I likely to get by changing it
for
a modern, condensing, boiler?

After a bit of googling I think I can answer my own question. An
efficiency improvement of 25% on 2000 litres/year (no idea whether
that's correct) at 41p/litre is about £205, so that pays back at 15
years. If that's correct, and unless there are any grants, it's worth
keeping the old boiler going for as long as reasonably possible.
Also to reinforce your decision, retro fitting a condensing boiler to
existing rads is not likely to achieve the stated efficiency. To get
even near the published figures, the flow/return temps have to be lower
and so the heat output from the rads will fall.
You will have to up the flow temp and sacrifice efficiency or fit new
bigger rads and allow for that in your capital outlay.

Thanks, that's something I hadn't considered.

Unless the rads were one the small side to start with, I suspect this is
less of an issue in many cases. Most systems are only running part load
for a good part of the heating season, and that is where the condensers
gain...

When I fitted a condenser here I left most of the rads untouched (apart
from one room that was never really warm enough). My system is weather
compensated, and quite often runs flow temperatures under 50 deg C, and
so gets full condensing efficiency (which ideally needs return temps
under 54 deg c). So there would have been no benefit in larger rads
other than on the very coldest days.


--
Cheers,

John.

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

On 19/03/2017 20:19, DJC wrote:
On 19/03/17 10:04, wrote:
On 19/03/2017 08:31, The Natural Philosopher wrote:
On 18/03/17 18:36, wrote:
What real world efficiency savings am I likely to get by changing it
for
a modern, condensing, boiler?
Not nearly as much as getting the insulation sorted.

Boiler should be the last thing you tackle.

The window frames are steel, mostly single-glazed but some have been
double-glazed. One of the early tasks will be tidying-up the windows and
looking for ways to fit (thin) double glazing panels to them - expect
another thread on this once we've moved-in!

Apart from windows and doors I don't think there's much scope to improve
the insulation, but I'll certainly be investigating what can be done.
The construction appears to be rendered concrete block but I don't know
yet whether there's a cavity.


If it was built since 1920s it will have a cavity as that was when it
became requirement everywhere.

My previous solid wall place was built in 1956




--
Cheers,

John.

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

On Sunday, 19 March 2017 17:19:28 UTC, Johnny B Good wrote:
On Sun, 19 Mar 2017 00:09:44 +0000, nospam wrote:
On 18/03/2017 18:36, wrote:
A while ago I asked about the possible perils of buying a listed house
(17thC timber-framed) - the survey results were so bad that I ran away
bravely. It now seems likely that I'll be buying an unlisted 1930s
"arts and crafts" style house that seems to be pretty solid (but the
survey is next week - :eeek!).
This house has a fairly old (20+ years?) Mistral oil-fired boiler,
which is certain to be non-condensing. I need to check but I think the
output is 160k BTU. My previous boiler experience has all been with gas
boilers.
What do I need to know that I may not know?
What real world efficiency savings am I likely to get by changing it
for a modern, condensing, boiler?

After a bit of googling I think I can answer my own question. An
efficiency improvement of 25% on 2000 litres/year (no idea whether
that's correct) at 41p/litre is about £205, so that pays back at 15
years. If that's correct, and unless there are any grants, it's worth
keeping the old boiler going for as long as reasonably possible.

It's the absence of such ROI reasoning that allowed the billions of
pounds to be frittered away on solar farms and wind turbines by the
government fulfilling the manifesto promises made purely to win votes
away from the Green Party here in the UK. I guess even the most basic
"Back of a pack of ciggies" long term investment costs analysis were too
much of an "Inconvenient Truth" to be raised as the entirely reasonable
objection to implementing such projects beyond the level of small scale
proof of concept.

I passed what I always assumed was a small wind generator today, it was spinning like a top. Yet only a light breeze... something is not adding up. I reckon it's a fake, and doesn't generate a thing.


NT