On 13 Dec 2023 at 23:18:19 GMT, alan_m wrote:

> On 13/12/2023 15:35, RJH wrote:
>> On 12 Dec 2023 at 09:45:47 GMT, Tim+ wrote:
>>
>>> Maybe outside mounting is worth considering? Relatively rare for gas
>>> boilers here but it seemed to be he normally in New Zealand.
>>>
>>> https://www.flexiheatuk.com/product/external-gas-boiler/
>>
>> Or a heat pump - £7500 grant available right now . . .
>
> If the system is that old the CH is probably designed for a very high
> flow temperature. £7500 may not make too much of a dent in the cost of
> modifying the rest of the system:)

IIUC, new rads - not the end of the world, but the heat pump survey* guy
mentioned 3 metre double units. Not sure where they'd go . . .

* as a condition of the grant application I had to get a £200 non-refundable
survey, which includes solar and a new EPC. That may be the way this installer
works - others may vary. But applicants have to go through an approved
installer to qualify for the grant.

It may be that my house isn't suitable - placing the unit will be tricky,
apparently. So waste of money if I decide not to go ahead - and I probably
won't, it's all been too vague and hard sell.

--
Cheers, Rob, Sheffield UK

On Thursday 14 December 2023 at 09:28:33 UTC, RJH wrote:
> > If the system is that old the CH is probably designed for a very high
> > flow temperature. £7500 may not make too much of a dent in the cost of
> > modifying the rest of the system:)

A Baxi Buggerit may still be on the old single-pipe system so completely new return pipes to all radiators would be needed.

> IIUC, new rads - not the end of the world, but the heat pump survey* guy
> mentioned 3 metre double units. Not sure where they'd go . . .

You could use fan assisted radiators eg Myson; they have a high output in a small size. A bit ugly and noisy though.

Owain

RJH <patchmoney@gmx.com> wrote:
> IIUC, new rads - not the end of the world, but the heat pump survey* guy
> mentioned 3 metre double units. Not sure where they'd go . . .

Could you get triple units, or increase the height?

If you know your room heat loss (the installer must have done the calcs, ask
to see them) you can choose rads to meet the output at the appropriate flow
temp - there are online calculators. There may be alternative options than
the one they've suggested.

> * as a condition of the grant application I had to get a £200
> non-refundable survey, which includes solar and a new EPC. That may be
> the way this installer works - others may vary. But applicants have to go
> through an approved installer to qualify for the grant.

It's probably just the installer wants paying for doing the survey, if you
choose not to go ahead. They don't need to do that, but it helps confirm
the customer isn't kicking tyres. If they're busy they probably don't want
to do the work on spec.

If your EPC is more than 10 years old you would need that doing for the
grant, and that costs ~£70-100 anyway. Not sure about solar, I think you
only need to do that for the ECO grant (where your energy company is paying
and they do a whole-house energy recommendation - insulation etc) rather
than the Boiler Upgrade grant (which is just for a heating replacement).

Have they registered the new EPC? (Check epcregister.com)

> It may be that my house isn't suitable - placing the unit will be tricky,
> apparently. So waste of money if I decide not to go ahead - and I probably
> won't, it's all been too vague and hard sell.

The heat loss calcs and EPC are likely useful even if you don't go ahead.
What was the problem with placing the unit - do you have an outside wall for
it? Are you in a tight site (flat, 2-up 2-down terrace or something)?

Vague and hard sell is not a good look though, I agree.

Theo

On Tuesday 12 December 2023 at 23:01:33 UTC, David Wade wrote:
> On 12/12/2023 22:03, Animal wrote:
> > On Tuesday 12 December 2023 at 03:17:40 UTC, Use-Author-Suppli...@127.1 wrote:
> >> Theo <theom...@chiark.greenend.org.uk> wrote:
> >> : Fredxx <fre...@spam.invalid> wrote:
> >> : > By way of example the 248436 is a 26 fin heat exchanger and new will
> >> : > cost ?5-600.
> >> : >
> >> : > While it is admirable to effect a repair, the economics of running an
> >> : > old boiler, plus the cost of this part assuming you can get it, makes it
> >> : > a no-brainer to upgrade to a more modern boiler.
> >>
> >> : I would agree, although the one we had was located in the chimney breast in
> >> : the living room. Installing a regular boiler would have meant moving it (to
> >> : an outside wall, likely in the kitchen), re-piping the heating and gas to
> >> : get there, and then doing something with the gaping hole in the fireplace.
> >> : (potentially adding a gas fire if you used that function)
> >>
> >> : That's a lot more work than just replacing a heat exchanger.
> >>
> >> : Another thought would be, if you're going to have to relocate the boiler
> >> : anyway, it might be worth looking at a heat pump. It might be say 2x
> >> : disruption compared to moving the boiler, but the unit can go outside which
> >> : might give you more options compared with a boiler that needs to be inside.
> >>
> >> : I agree with not throwing good money after bad though. If I were the OP,
> >> : since the boiler is still working, I'd probably be planning my next move -
> >> : which would likely mean something more substantial than trying to source a
> >> : heat exchanger to keep the old girl staggering along.
> >> My thanks to everyone who followed-up. There were some useful pointers.
> >>
> >> I'll check out
> >> https://boilerrecycling.co.uk/product-category/heat-exchangers?filter_brand=baxi
> >> soon.
> >>
> >> My main problem with a wall mounted condensing boiler is that there is
> >> nowhere it could be installed without significantly spoiling the room it
> >> would have to go in, probably the kitchen. As you suggest there is a lot
> >> more work, plumbing involved. The built-in obsolescence of modern boilers
> >> also irritates me. Our current one must be about 50 years old. No modern
> >> condensing one is going to even get close to that!
> >>
> >> It is pity that Baxi discontinued their 'HE' BBU which would have been
> >> something at least worth considering.
> >>
> >> The BG engineer who serviced it said the heat exchanger had a tiny leak and
> >> that at some stage it will fail. The trouble is I don't have any idea when.
> >> Unfortunately I was out at work when he came (due to BG's admin mistake) so
> >> did not get a chance to see where the leak was myself and ask him about it.
> >>
> >> I am not even very sure of the construction of this particular HE, from
> >> photos on suppliers websites and the engineering drawings on Baxi's website.
> >> It appears to consist of two (upper and lower) cast iron sections held
> >> together with bolts. I read elsewhere that some kind of gaskets may be
> >> involved in sealing the two sections together, and that any leaks would be
> >> more likely in/around the gaskets (which presumably can be replaced?) rather
> >> than in the the cast iron sections. I've really no idea though. I would be
> >> interested to know if anyone has taken one of these apart or has seen one
> >> close up.
> >>
> >> Cheers
> >> Tom
> >>
> >> : Theo
> >
> > So in summary you've no idea whether you need a new HX. Find out if it leaks, and if it does tell us its construction. Leaks are fixable many ways.
> You are going to struggle with this. You say its in good condition, yet
> if its deteriorated enough for a leak in the heat exchanger, it isn't.
>
> Whilst these things can be repaired, won't you need to find a GasSafe
> registered fitter to do the work?

They're not the usual choice for HX repairs

> I am not sure any one would want to do
> this and certify it as "safe" ...

Do you need it certified? If I get my car rad fixed I don't get anything certified. If I put waterglass leak sealant in a CH system I don't need to get it certified.

On 10/12/2023 21:38, Tim+ wrote:
> <Use-Author-Supplied-Address-Header@[127.1]> wrote:
>> At some stage I am going to need a replacement heat exchanger for an elderly
>> but otherwise in GWO Baxi Bermuda 45/4E BBU.
>>
>> Baxi have confirmed that neither the original part (Baxi part no. 233910, GC
>> no. 193156) or its replacement (Baxi part no. 248436, GC no. 193156, now
>> classified as 'obsolete') are available.
>>
>> I have checked with many UK heating parts suppliers who stock genuine Baxi
>> parts. None have this part or can get hold of it.
>>
>> My question is: Are there any third party manufacturers/suppliers, in the UK
>> or abroad, who can supply a compatible part? In the past I'm sure I read
>> that there were Chinese manufacturers of Baxi compatible parts but I have
>> not managed find any references for this particular part.
>>
>> Many thanks
>> Tom
>>
>> Ps. Before anyone comments, I know that BBUs are less efficient than modern
>> wall mounted condensing boilers.
>> Pps. The email address in the header is just a spam-trap.
>
> Whilst I can empathise with keeping an old any trusty appliance going, when
> it comes to the Baxi Bermuda I really do think it’s time to thank it for
> its long years of service and sling it in a skip (when it dies). That or
> turn it into an “installation” in Tate Modern.
>
I slung mine in the local amenity tip metal skip 20 years ago.
'Sling' needs to be qualified by 'struggled on my own' on account
of its significant weight.

These cast iron heat exchangers are bullet proof but what fails is
the bolts that hold the two halves together.

Chap across the road still has his and a few years back was also
looking for a possible new heat exchanger.

If the property uses class 2 flue blocks then they are more efficient
than believed because the wall of the bedroom above gets the extra
heat from these flue blocks. The houses on my estate had much smaller
radiators in this bedroom compared to the other bedrooms for this reason.

> Do you plan to replace the heat exchanger yourself? Even if you do manage
> to find a Chinese heat exchanger you might well find it difficult to find a
> fitter who will fit a heat exchanger to such an obsolete boiler.
>
> Tim
>
>
The galvanised metal casing also tends to rot away.

On 11/12/2023 20:29, John Rumm wrote:
> On 11/12/2023 11:29, Theo wrote:
>> Fredxx <fredxx@spam.invalid> wrote:
>>> By way of example the 248436 is a 26 fin heat exchanger and new will
>>> cost £5-600.
>>>
>>> While it is admirable to effect a repair, the economics of running an
>>> old boiler, plus the cost of this part assuming you can get it, makes it
>>> a no-brainer to upgrade to a more modern boiler.
>>
>> I would agree, although the one we had was located in the chimney
>> breast in
>> the living room.  Installing a regular boiler would have meant moving
>> it (to
>> an outside wall, likely in the kitchen), re-piping the heating and gas to
>> get there, and then doing something with the gaping hole in the
>> fireplace.
>> (potentially adding a gas fire if you used that function)
>>
>> That's a lot more work than just replacing a heat exchanger.
>>
>> Another thought would be, if you're going to have to relocate the boiler
>> anyway, it might be worth looking at a heat pump.  It might be say 2x
>> disruption compared to moving the boiler, but the unit can go outside
>> which
>> might give you more options compared with a boiler that needs to be
>> inside.
>
> There are boilers designed for external installation as well...
>
>

Baxi did make and sell a condensing replacement for their old
baxi bermuda back boilers but they took it off the market after
about a year from what I remember. Not too many installers
wanted to fit one because it required a new flu liner which
made it a no-go for properties with class 2 flue blocks (and
there must be hundreds of thousands of that type of late 60's,
70's and early 80's houses).

On 14/12/2023 12:31, Owain Lastname wrote:
> On Thursday 14 December 2023 at 09:28:33 UTC, RJH wrote:
>>> If the system is that old the CH is probably designed for a very high
>>> flow temperature. £7500 may not make too much of a dent in the cost of
>>> modifying the rest of the system:)
>
> A Baxi Buggerit may still be on the old single-pipe system so completely new return pipes to all radiators would be needed.
>
50 years old means the house was built circa 1973, so it will probably
have proper dual 28/20/15mm pipe runs to the hot tank (C plan) and
rads via a pump.

On 14 Dec 2023 at 18:24:02 GMT, Theo wrote:

> RJH <patchmoney@gmx.com> wrote:
>> IIUC, new rads - not the end of the world, but the heat pump survey* guy
>> mentioned 3 metre double units. Not sure where they'd go . . .
>
> Could you get triple units, or increase the height?
>
Yes, probably. But if it's going to take all this upheaval I'd rather look at
underfloor heating.

> If you know your room heat loss (the installer must have done the calcs, ask
> to see them) you can choose rads to meet the output at the appropriate flow
> temp - there are online calculators. There may be alternative options than
> the one they've suggested.
>

I'm going to wait for the report.

I have done some calculations, but they don't correspond to measurements such
as heat loss and temperature reached in one particular room. The culprit is I
think a bay window. Despite dry lining, heavy curtains, cavity fill, a
seemingly insulated bay roof (snow took a while to melt), and what look to me
to be decent DG units, the temperature in the room is always a couple of
degrees below other rooms, despite an oversized radiator, and drops more
quickly than other rooms.

No real idea what's going on. I'm insulating the floor at the moment

>> * as a condition of the grant application I had to get a £200
>> non-refundable survey, which includes solar and a new EPC. That may be
>> the way this installer works - others may vary. But applicants have to go
>> through an approved installer to qualify for the grant.
>
> It's probably just the installer wants paying for doing the survey, if you
> choose not to go ahead. They don't need to do that, but it helps confirm
> the customer isn't kicking tyres. If they're busy they probably don't want
> to do the work on spec.
>
> If your EPC is more than 10 years old you would need that doing for the
> grant, and that costs ~£70-100 anyway. Not sure about solar, I think you
> only need to do that for the ECO grant (where your energy company is paying
> and they do a whole-house energy recommendation - insulation etc) rather
> than the Boiler Upgrade grant (which is just for a heating replacement).
>
> Have they registered the new EPC? (Check epcregister.com)

I'd like a new EPC as a lot of work was done since the 2017 original. Nothing
on the regsiter yet - survey done 5 days ago.

>
>> It may be that my house isn't suitable - placing the unit will be tricky,
>> apparently. So waste of money if I decide not to go ahead - and I probably
>> won't, it's all been too vague and hard sell.
>
> The heat loss calcs and EPC are likely useful even if you don't go ahead.
> What was the problem with placing the unit - do you have an outside wall for
> it? Are you in a tight site (flat, 2-up 2-down terrace or something)?
>

It's a 1920 semi. I'm not too sure what the problem is TBH - just a lot of
tutting as he walked around.

> Vague and hard sell is not a good look though, I agree.
>
> Theo

--
Cheers, Rob, Sheffield UK

RJH <patchmoney@gmx.com> wrote:
> On 14 Dec 2023 at 18:24:02 GMT, Theo wrote:
>
> > RJH <patchmoney@gmx.com> wrote:
> >> IIUC, new rads - not the end of the world, but the heat pump survey* guy
> >> mentioned 3 metre double units. Not sure where they'd go . . .
> >
> > Could you get triple units, or increase the height?
> >
> Yes, probably. But if it's going to take all this upheaval I'd rather look at
> underfloor heating.

Depends how much faff it is to insulate under the UFH - no point just
heating the ground. Suspended or solid floors?

> I'm going to wait for the report.
>
> I have done some calculations, but they don't correspond to measurements such
> as heat loss and temperature reached in one particular room. The culprit is I
> think a bay window. Despite dry lining, heavy curtains, cavity fill, a
> seemingly insulated bay roof (snow took a while to melt), and what look to me
> to be decent DG units, the temperature in the room is always a couple of
> degrees below other rooms, despite an oversized radiator, and drops more
> quickly than other rooms.
>
> No real idea what's going on. I'm insulating the floor at the moment

It would be worth finding out, because if you can solve that problem your
bills will go down, irrespective of heating source.

In my case, I have a couple of rooms upstairs with about 3.6m x 0.6m of what
looks to be perfectly fine 20yo UPVC double glazing, but actually there's a
lot of heat loss through the glass. I fitted some cellular blinds (Hoppvals
from Ikea, cut to size with a hacksaw) and it made a big difference.

If you can get hold of a thermal camera it would be useful to offer clues.

> > Have they registered the new EPC? (Check epcregister.com)
>
> I'd like a new EPC as a lot of work was done since the 2017 original. Nothing
> on the regsiter yet - survey done 5 days ago.

I think for some of the grants you want an EPC score that's not awful but
not great, and they won't pay if your EPC is too good. (not sure if that's
current, I'm not up to date with all the different kinds at the moment)

> >> It may be that my house isn't suitable - placing the unit will be tricky,
> >> apparently. So waste of money if I decide not to go ahead - and I probably
> >> won't, it's all been too vague and hard sell.
> >
> > The heat loss calcs and EPC are likely useful even if you don't go ahead.
> > What was the problem with placing the unit - do you have an outside wall for
> > it? Are you in a tight site (flat, 2-up 2-down terrace or something)?
> >
>
> It's a 1920 semi. I'm not too sure what the problem is TBH - just a lot of
> tutting as he walked around.

There might be something about proximity to neighbours and noise nuisance.
Do you have a ground floor spot on the wall that's at least 2m from the
boundary, where you might be able to site a concrete pad and run services
(electric, central heating pipes) to? Better if it's not right next to a
sleeping room.

It is also possible to site the units some distance away with buried
pipework, with some extra cost and loss of efficiency. A house down the
road has theirs in the front garden, about 5m from the house, strategically
located behind a bush. (I bet they didn't ask the bush how it felt about
being blown cold air all winter)

Theo

On 15 Dec 2023 at 22:12:26 GMT, Theo wrote:

> RJH <patchmoney@gmx.com> wrote:
>> On 14 Dec 2023 at 18:24:02 GMT, Theo wrote:
>>
>>> RJH <patchmoney@gmx.com> wrote:
>>>> IIUC, new rads - not the end of the world, but the heat pump survey* guy
>>>> mentioned 3 metre double units. Not sure where they'd go . . .
>>>
>>> Could you get triple units, or increase the height?
>>>
>> Yes, probably. But if it's going to take all this upheaval I'd rather look at
>> underfloor heating.
>
> Depends how much faff it is to insulate under the UFH - no point just
> heating the ground. Suspended or solid floors?
>

Indeed - suspended timber, cellar underneath.

>> I'm going to wait for the report.
>>
>> I have done some calculations, but they don't correspond to measurements such
>> as heat loss and temperature reached in one particular room. The culprit is I
>> think a bay window. Despite dry lining, heavy curtains, cavity fill, a
>> seemingly insulated bay roof (snow took a while to melt), and what look to me
>> to be decent DG units, the temperature in the room is always a couple of
>> degrees below other rooms, despite an oversized radiator, and drops more
>> quickly than other rooms.
>>
>> No real idea what's going on. I'm insulating the floor at the moment
>
> It would be worth finding out, because if you can solve that problem your
> bills will go down, irrespective of heating source.
>

Pretty sure it's a combination of draughts (which I'm dealing with) and
something I can't identify with the windows. They *look* decent - wide glass
gap, kite marked. And the spot temperature of the curtains is fairly decent,
not far off room temperature. But the cold air that pours out of gaps suggests
something's going on.

> In my case, I have a couple of rooms upstairs with about 3.6m x 0.6m of what
> looks to be perfectly fine 20yo UPVC double glazing, but actually there's a
> lot of heat loss through the glass. I fitted some cellular blinds (Hoppvals
> from Ikea, cut to size with a hacksaw) and it made a big difference.
>

Issue is the windows are quite big - 2m high, and 3m fitted width. And being a
bay it'd be nice if they butted up to each other. So likely bespoke, so
expensive, and I have looked at fitted shutters but don't have the money right
now.

> If you can get hold of a thermal camera it would be useful to offer clues.

Yes, borrowed one last year, will try again. Remember getting confused around
windows with emissivity of the glass but I'm sure it's doable.

>
>>> Have they registered the new EPC? (Check epcregister.com)
>>
>> I'd like a new EPC as a lot of work was done since the 2017 original. Nothing
>> on the regsiter yet - survey done 5 days ago.
>
> I think for some of the grants you want an EPC score that's not awful but
> not great, and they won't pay if your EPC is too good. (not sure if that's
> current, I'm not up to date with all the different kinds at the moment)
>
>>>> It may be that my house isn't suitable - placing the unit will be tricky,
>>>> apparently. So waste of money if I decide not to go ahead - and I probably
>>>> won't, it's all been too vague and hard sell.
>>>
>>> The heat loss calcs and EPC are likely useful even if you don't go ahead.
>>> What was the problem with placing the unit - do you have an outside wall for
>>> it? Are you in a tight site (flat, 2-up 2-down terrace or something)?
>>>
>>
>> It's a 1920 semi. I'm not too sure what the problem is TBH - just a lot of
>> tutting as he walked around.
>
> There might be something about proximity to neighbours and noise nuisance.
> Do you have a ground floor spot on the wall that's at least 2m from the
> boundary, where you might be able to site a concrete pad and run services
> (electric, central heating pipes) to? Better if it's not right next to a
> sleeping room.
>
> It is also possible to site the units some distance away with buried
> pipework, with some extra cost and loss of efficiency. A house down the
> road has theirs in the front garden, about 5m from the house, strategically
> located behind a bush. (I bet they didn't ask the bush how it felt about
> being blown cold air all winter)
>

I'll see what the report says - although I'm slowly coming to accepting the
possibility it's a con. This is what's promised:

https://www.apex-surveys.co.uk/heatingsurveys
https://www.apex-surveys.co.uk/solarsurveys

Within a couple of days. It's been 5 and still no word, and he wasn't here
long - maybe 20 minutes. I can't see how he took '360 photos and a walk
through video', plus the rest of it.

We'll see :-)

--
Cheers, Rob, Sheffield UK

On 16 Dec 2023 at 10:55:12 GMT, RJH wrote:

>> It would be worth finding out, because if you can solve that problem your
>> bills will go down, irrespective of heating source.
>>
>
> Pretty sure it's a combination of draughts (which I'm dealing with) and
> something I can't identify with the windows. They *look* decent - wide glass
> gap, kite marked. And the spot temperature of the curtains is fairly decent,
> not far off room temperature. But the cold air that pours out of gaps suggests
> something's going on.

Gaps in the curtains - not the frames etc!
--
Cheers, Rob, Sheffield UK

RJH <patchmoney@gmx.com> wrote:
> On 15 Dec 2023 at 22:12:26 GMT, Theo wrote:
>
> > Depends how much faff it is to insulate under the UFH - no point just
> > heating the ground. Suspended or solid floors?
> >
>
> Indeed - suspended timber, cellar underneath.

OK, so I suppose you need to decide whether you're heating the cellar (and
insulating that) or heating the room and insulating the floor so the cellar
is 'outside'.

> Issue is the windows are quite big - 2m high, and 3m fitted width. And
> being a bay it'd be nice if they butted up to each other. So likely
> bespoke, so expensive, and I have looked at fitted shutters but don't have
> the money right now.

If you can rule out leaks through the frames (eg old aluminium without
thermal breaks) maybe worth considering replacing the sealed unit while
keeping the frames?

eg https://www.sealedunitsonline.co.uk/
has a 3x2m unit with double 6mm Planitherm glass at about £160, or £180-240
for triple glazed. I would probably go with a supplier who gives a U-value
calculation, but gives an idea.

(in my case they put the glazing beads on the outside, so it's a scaffolding
job to change the sealed units)

> > If you can get hold of a thermal camera it would be useful to offer clues.
>
> Yes, borrowed one last year, will try again. Remember getting confused
> around windows with emissivity of the glass but I'm sure it's doable.

On a cold night, briefly touch the frame, the glass and the surrounding wall
in the room - which feels coldest? Fingers sense conduction and aren't so
fussy about emissivity.

> I'll see what the report says - although I'm slowly coming to accepting the
> possibility it's a con. This is what's promised:
>
> https://www.apex-surveys.co.uk/heatingsurveys
> https://www.apex-surveys.co.uk/solarsurveys

That looks like the right kind of words in the right order, so that's
something.

> Within a couple of days. It's been 5 and still no word, and he wasn't here
> long - maybe 20 minutes. I can't see how he took '360 photos and a walk
> through video', plus the rest of it.

For the heat loss you need room measurements, sizes of window/door openings,
and the construction of all the surfaces (walls/roof/floor/etc). Does sound
a bit much to do in 20 minutes, although a laser measure can do the
measurements quick and some of them hook into the software they use (my
Bosch does Bluetooth but to a useless app, however people have written
alternative drivers for Linux etc).

> We'll see :-)

Do keep us posted :)

Theo

On 16 Dec 2023 at 13:10:27 GMT, Theo wrote:

> RJH <patchmoney@gmx.com> wrote:
>> On 15 Dec 2023 at 22:12:26 GMT, Theo wrote:
>
>> Issue is the windows are quite big - 2m high, and 3m fitted width. And
>> being a bay it'd be nice if they butted up to each other. So likely
>> bespoke, so expensive, and I have looked at fitted shutters but don't have
>> the money right now.
>
> If you can rule out leaks through the frames (eg old aluminium without
> thermal breaks) maybe worth considering replacing the sealed unit while
> keeping the frames?
>
> eg https://www.sealedunitsonline.co.uk/
> has a 3x2m unit with double 6mm Planitherm glass at about £160, or £180-240
> for triple glazed. I would probably go with a supplier who gives a U-value
> calculation, but gives an idea.

Are you sure - 3m x 2m is huge! This is a bay made up of 6 units.

The biggest single unit is 150cm w x 90cm h - that seems to be coming out at
£180? So back of a fag packet calculation about £800 for all 6 panes . . .

>>> If you can get hold of a thermal camera it would be useful to offer clues.
>>
>> Yes, borrowed one last year, will try again. Remember getting confused
>> around windows with emissivity of the glass but I'm sure it's doable.
>
> On a cold night, briefly touch the frame, the glass and the surrounding wall
> in the room - which feels coldest? Fingers sense conduction and aren't so
> fussy about emissivity.
>
I'm guessing the glass will feel considerably colder (it is right now, outside
10C, inside 18C); I'll give it a go when it's colder.

>> I'll see what the report says - although I'm slowly coming to accepting the
>> possibility it's a con. This is what's promised:
>>
>> https://www.apex-surveys.co.uk/heatingsurveys
>> https://www.apex-surveys.co.uk/solarsurveys
>
> That looks like the right kind of words in the right order, so that's
> something.
>
>> Within a couple of days. It's been 5 and still no word, and he wasn't here
>> long - maybe 20 minutes. I can't see how he took '360 photos and a walk
>> through video', plus the rest of it.
>
> For the heat loss you need room measurements, sizes of window/door openings,
> and the construction of all the surfaces (walls/roof/floor/etc). Does sound
> a bit much to do in 20 minutes, although a laser measure can do the
> measurements quick and some of them hook into the software they use (my
> Bosch does Bluetooth but to a useless app, however people have written
> alternative drivers for Linux etc).
>
>> We'll see :-)
>
> Do keep us posted :)
>

FWIW, will do!

--
Cheers, Rob, Sheffield UK

RJH <patchmoney@gmx.com> wrote:
> On 16 Dec 2023 at 13:10:27 GMT, Theo wrote:
>
> > RJH <patchmoney@gmx.com> wrote:
> >> On 15 Dec 2023 at 22:12:26 GMT, Theo wrote:
> >
> >> Issue is the windows are quite big - 2m high, and 3m fitted width. And
> >> being a bay it'd be nice if they butted up to each other. So likely
> >> bespoke, so expensive, and I have looked at fitted shutters but don't have
> >> the money right now.
> >
> > If you can rule out leaks through the frames (eg old aluminium without
> > thermal breaks) maybe worth considering replacing the sealed unit while
> > keeping the frames?
> >
> > eg https://www.sealedunitsonline.co.uk/
> > has a 3x2m unit with double 6mm Planitherm glass at about £160, or £180-240
> > for triple glazed. I would probably go with a supplier who gives a U-value
> > calculation, but gives an idea.
>
> Are you sure - 3m x 2m is huge! This is a bay made up of 6 units.

Oh, I must have put it in cm not mm :-( 3m x 2m comes in at 2k, which is not
such a good deal.

> The biggest single unit is 150cm w x 90cm h - that seems to be coming out at
> £180? So back of a fag packet calculation about £800 for all 6 panes . . .

That sounds plausible. Cost can probably be shaved a bit using a local
supplier.

> >>> If you can get hold of a thermal camera it would be useful to offer clues.
> >>
> >> Yes, borrowed one last year, will try again. Remember getting confused
> >> around windows with emissivity of the glass but I'm sure it's doable.
> >
> > On a cold night, briefly touch the frame, the glass and the surrounding wall
> > in the room - which feels coldest? Fingers sense conduction and aren't so
> > fussy about emissivity.
> >
> I'm guessing the glass will feel considerably colder (it is right now, outside
> 10C, inside 18C); I'll give it a go when it's colder.

Yes, you can feel what's conductively colder. It won't account for leaks,
but if you've already plugged those it suggests conduction is what's
remaining.

Theo

Cant you put it in the loft - if you have one. Thats where mine went when I replaced my Baxi this year. Then the wife fancied a log burner so that went in the chimney breast

sintv <sinclairtv@gmail.com> wrote:
: Cant you put it in the loft - if you have one. Thats where mine went when I replaced my Baxi this year. Then the wife fancied a log burner so that went in the chimney breast

Not easily. Almost all of the loft is now part of a loft extension.

Tom.

Ps. The email address in the header is just a spam-trap.
--
Tom Crane, Dept. Physics, Royal Holloway, University of London, Egham Hill,
Egham, Surrey, TW20 0EX, England.
Email: T dot Crane at rhul dot ac dot uk

Andrew <Andrew97d@btinternet.com> wrote:
: On 10/12/2023 21:38, Tim+ wrote:
: > <Use-Author-Supplied-Address-Header@[127.1]> wrote:
: >> At some stage I am going to need a replacement heat exchanger for an elderly
: >> but otherwise in GWO Baxi Bermuda 45/4E BBU.
: >>
: >> Baxi have confirmed that neither the original part (Baxi part no. 233910, GC
: >> no. 193156) or its replacement (Baxi part no. 248436, GC no. 193156, now
: >> classified as 'obsolete') are available.
: >>
: >> I have checked with many UK heating parts suppliers who stock genuine Baxi
: >> parts. None have this part or can get hold of it.
: >>
: >> My question is: Are there any third party manufacturers/suppliers, in the UK
: >> or abroad, who can supply a compatible part? In the past I'm sure I read
: >> that there were Chinese manufacturers of Baxi compatible parts but I have
: >> not managed find any references for this particular part.
: >>
: >> Many thanks
: >> Tom
: >>
: >> Ps. Before anyone comments, I know that BBUs are less efficient than modern
: >> wall mounted condensing boilers.
: >> Pps. The email address in the header is just a spam-trap.
: >
: > Whilst I can empathise with keeping an old any trusty appliance going, when
: > it comes to the Baxi Bermuda I really do think it?s time to thank it for
: > its long years of service and sling it in a skip (when it dies). That or
: > turn it into an ?installation? in Tate Modern.
: >
: I slung mine in the local amenity tip metal skip 20 years ago.
: 'Sling' needs to be qualified by 'struggled on my own' on account
: of its significant weight.

: These cast iron heat exchangers are bullet proof but what fails is
: the bolts that hold the two halves together.

: Chap across the road still has his and a few years back was also
: looking for a possible new heat exchanger.

: If the property uses class 2 flue blocks then they are more efficient
: than believed because the wall of the bedroom above gets the extra
: heat from these flue blocks. The houses on my estate had much smaller
: radiators in this bedroom compared to the other bedrooms for this reason.

: > Do you plan to replace the heat exchanger yourself? Even if you do manage
: > to find a Chinese heat exchanger you might well find it difficult to find a
: > fitter who will fit a heat exchanger to such an obsolete boiler.
: >
: > Tim
: >
: >
: The galvanised metal casing also tends to rot away.

I am curious about the internal plumbing of the HE, not having seen mine
for reasons explained above.

>From the engineering drawing on Baxi's website, the Boiler Return inlet
appears to be part of the lower cast iron section and the two Boiler Flow
outlets part of the upper cast iron section. Are these two sections' water
paths joined at both ends where the bolts are, only at one end or along the
full length?

Regards
Tom.

Ps. The email address in the header is just a spam-trap.
--
Tom Crane, Dept. Physics, Royal Holloway, University of London, Egham Hill,
Egham, Surrey, TW20 0EX, England.
Email: T dot Crane at rhul dot ac dot uk

On Saturday 16 December 2023 at 10:55:17 UTC, RJH wrote:
> On 15 Dec 2023 at 22:12:26 GMT, Theo wrote:
>
> > RJH <patch...@gmx.com> wrote:
> >> On 14 Dec 2023 at 18:24:02 GMT, Theo wrote:
> >>
> >>> RJH <patch...@gmx.com> wrote:
> >>>> IIUC, new rads - not the end of the world, but the heat pump survey* guy
> >>>> mentioned 3 metre double units. Not sure where they'd go . . .
> >>>
> >>> Could you get triple units, or increase the height?
> >>>
> >> Yes, probably. But if it's going to take all this upheaval I'd rather look at
> >> underfloor heating.
> >
> > Depends how much faff it is to insulate under the UFH - no point just
> > heating the ground. Suspended or solid floors?
> >
> Indeed - suspended timber, cellar underneath.
> >> I'm going to wait for the report.
> >>
> >> I have done some calculations, but they don't correspond to measurements such
> >> as heat loss and temperature reached in one particular room. The culprit is I
> >> think a bay window. Despite dry lining, heavy curtains, cavity fill, a
> >> seemingly insulated bay roof (snow took a while to melt), and what look to me
> >> to be decent DG units, the temperature in the room is always a couple of
> >> degrees below other rooms, despite an oversized radiator, and drops more
> >> quickly than other rooms.
> >>
> >> No real idea what's going on. I'm insulating the floor at the moment
> >
> > It would be worth finding out, because if you can solve that problem your
> > bills will go down, irrespective of heating source.
> >
> Pretty sure it's a combination of draughts (which I'm dealing with) and
> something I can't identify with the windows. They *look* decent - wide glass
> gap, kite marked. And the spot temperature of the curtains is fairly decent,
> not far off room temperature. But the cold air that pours out of gaps suggests
> something's going on.
> > In my case, I have a couple of rooms upstairs with about 3.6m x 0.6m of what
> > looks to be perfectly fine 20yo UPVC double glazing, but actually there's a
> > lot of heat loss through the glass. I fitted some cellular blinds (Hoppvals
> > from Ikea, cut to size with a hacksaw) and it made a big difference.
> >
> Issue is the windows are quite big - 2m high, and 3m fitted width. And being a
> bay it'd be nice if they butted up to each other. So likely bespoke, so
> expensive, and I have looked at fitted shutters but don't have the money right
> now.
> > If you can get hold of a thermal camera it would be useful to offer clues.
> Yes, borrowed one last year, will try again. Remember getting confused around
> windows with emissivity of the glass but I'm sure it's doable.
> >
> >>> Have they registered the new EPC? (Check epcregister.com)
> >>
> >> I'd like a new EPC as a lot of work was done since the 2017 original. Nothing
> >> on the regsiter yet - survey done 5 days ago.
> >
> > I think for some of the grants you want an EPC score that's not awful but
> > not great, and they won't pay if your EPC is too good. (not sure if that's
> > current, I'm not up to date with all the different kinds at the moment)
> >
> >>>> It may be that my house isn't suitable - placing the unit will be tricky,
> >>>> apparently. So waste of money if I decide not to go ahead - and I probably
> >>>> won't, it's all been too vague and hard sell.
> >>>
> >>> The heat loss calcs and EPC are likely useful even if you don't go ahead.
> >>> What was the problem with placing the unit - do you have an outside wall for
> >>> it? Are you in a tight site (flat, 2-up 2-down terrace or something)?
> >>>
> >>
> >> It's a 1920 semi. I'm not too sure what the problem is TBH - just a lot of
> >> tutting as he walked around.
> >
> > There might be something about proximity to neighbours and noise nuisance.
> > Do you have a ground floor spot on the wall that's at least 2m from the
> > boundary, where you might be able to site a concrete pad and run services
> > (electric, central heating pipes) to? Better if it's not right next to a
> > sleeping room.
> >
> > It is also possible to site the units some distance away with buried
> > pipework, with some extra cost and loss of efficiency. A house down the
> > road has theirs in the front garden, about 5m from the house, strategically
> > located behind a bush. (I bet they didn't ask the bush how it felt about
> > being blown cold air all winter)
> >
> I'll see what the report says - although I'm slowly coming to accepting the
> possibility it's a con. This is what's promised:
>
> https://www.apex-surveys.co.uk/heatingsurveys
> https://www.apex-surveys.co.uk/solarsurveys
>
> Within a couple of days. It's been 5 and still no word, and he wasn't here
> long - maybe 20 minutes. I can't see how he took '360 photos and a walk
> through video', plus the rest of it.
>
> We'll see :-)

Compared to gas, ASHP costs much more upfront, more per therm output, is noisy, takes up more space, and efficiency takes a dump when it gets near freezing. The increased cost per output is being hidden by insisting on adding insulation when installing. So yeah, it makes as much sense as many green measures.

On 20/12/2023 06:32, Animal wrote:
> On Saturday 16 December 2023 at 10:55:17 UTC, RJH wrote:
>> On 15 Dec 2023 at 22:12:26 GMT, Theo wrote:
>>
>>> RJH <patch...@gmx.com> wrote:
>>>> On 14 Dec 2023 at 18:24:02 GMT, Theo wrote:
>>>>
>>>>> RJH <patch...@gmx.com> wrote:
>>>>>> IIUC, new rads - not the end of the world, but the heat pump survey* guy
>>>>>> mentioned 3 metre double units. Not sure where they'd go . . .
>>>>>
>>>>> Could you get triple units, or increase the height?
>>>>>
>>>> Yes, probably. But if it's going to take all this upheaval I'd rather look at
>>>> underfloor heating.
>>>
>>> Depends how much faff it is to insulate under the UFH - no point just
>>> heating the ground. Suspended or solid floors?
>>>
>> Indeed - suspended timber, cellar underneath.
>>>> I'm going to wait for the report.
>>>>
>>>> I have done some calculations, but they don't correspond to measurements such
>>>> as heat loss and temperature reached in one particular room. The culprit is I
>>>> think a bay window. Despite dry lining, heavy curtains, cavity fill, a
>>>> seemingly insulated bay roof (snow took a while to melt), and what look to me
>>>> to be decent DG units, the temperature in the room is always a couple of
>>>> degrees below other rooms, despite an oversized radiator, and drops more
>>>> quickly than other rooms.
>>>>
>>>> No real idea what's going on. I'm insulating the floor at the moment
>>>
>>> It would be worth finding out, because if you can solve that problem your
>>> bills will go down, irrespective of heating source.
>>>
>> Pretty sure it's a combination of draughts (which I'm dealing with) and
>> something I can't identify with the windows. They *look* decent - wide glass
>> gap, kite marked. And the spot temperature of the curtains is fairly decent,
>> not far off room temperature. But the cold air that pours out of gaps suggests
>> something's going on.
>>> In my case, I have a couple of rooms upstairs with about 3.6m x 0.6m of what
>>> looks to be perfectly fine 20yo UPVC double glazing, but actually there's a
>>> lot of heat loss through the glass. I fitted some cellular blinds (Hoppvals
>>> from Ikea, cut to size with a hacksaw) and it made a big difference.
>>>
>> Issue is the windows are quite big - 2m high, and 3m fitted width. And being a
>> bay it'd be nice if they butted up to each other. So likely bespoke, so
>> expensive, and I have looked at fitted shutters but don't have the money right
>> now.
>>> If you can get hold of a thermal camera it would be useful to offer clues.
>> Yes, borrowed one last year, will try again. Remember getting confused around
>> windows with emissivity of the glass but I'm sure it's doable.
>>>
>>>>> Have they registered the new EPC? (Check epcregister.com)
>>>>
>>>> I'd like a new EPC as a lot of work was done since the 2017 original. Nothing
>>>> on the regsiter yet - survey done 5 days ago.
>>>
>>> I think for some of the grants you want an EPC score that's not awful but
>>> not great, and they won't pay if your EPC is too good. (not sure if that's
>>> current, I'm not up to date with all the different kinds at the moment)
>>>
>>>>>> It may be that my house isn't suitable - placing the unit will be tricky,
>>>>>> apparently. So waste of money if I decide not to go ahead - and I probably
>>>>>> won't, it's all been too vague and hard sell.
>>>>>
>>>>> The heat loss calcs and EPC are likely useful even if you don't go ahead.
>>>>> What was the problem with placing the unit - do you have an outside wall for
>>>>> it? Are you in a tight site (flat, 2-up 2-down terrace or something)?
>>>>>
>>>>
>>>> It's a 1920 semi. I'm not too sure what the problem is TBH - just a lot of
>>>> tutting as he walked around.
>>>
>>> There might be something about proximity to neighbours and noise nuisance.
>>> Do you have a ground floor spot on the wall that's at least 2m from the
>>> boundary, where you might be able to site a concrete pad and run services
>>> (electric, central heating pipes) to? Better if it's not right next to a
>>> sleeping room.
>>>
>>> It is also possible to site the units some distance away with buried
>>> pipework, with some extra cost and loss of efficiency. A house down the
>>> road has theirs in the front garden, about 5m from the house, strategically
>>> located behind a bush. (I bet they didn't ask the bush how it felt about
>>> being blown cold air all winter)
>>>
>> I'll see what the report says - although I'm slowly coming to accepting the
>> possibility it's a con. This is what's promised:
>>
>> https://www.apex-surveys.co.uk/heatingsurveys
>> https://www.apex-surveys.co.uk/solarsurveys
>>
>> Within a couple of days. It's been 5 and still no word, and he wasn't here
>> long - maybe 20 minutes. I can't see how he took '360 photos and a walk
>> through video', plus the rest of it.
>>
>> We'll see :-)
>
> Compared to gas, ASHP costs much more upfront, more per therm output, is noisy, takes up more space, and efficiency takes a dump when it gets near freezing. The increased cost per output is being hidden by insisting on adding insulation when installing. So yeah, it makes as much sense as many green measures.
>
>
I think we are wedded to the past with water in radiators to heat the
house.

I love my split AC units but I do have enough space outside for a couple
of outside units.

The only thing that keeps the gas cheaper is the stupid pricing for
electricity,

Dave

On 20/12/2023 09:04, David Wade wrote:

>
> The only thing that keeps the gas cheaper is the stupid pricing for
> electricity,
>
Well that's the price you pay for mediaeval windmills.

> Dave
>

--
“But what a weak barrier is truth when it stands in the way of an
hypothesis!”

Mary Wollstonecraft

On 20/12/2023 09:04, David Wade wrote:
> On 20/12/2023 06:32, Animal wrote:

>> Compared to gas, ASHP costs much more upfront, more per therm output,
>> is noisy, takes up more space, and efficiency takes a dump when it
>> gets near freezing. The increased cost per output is being hidden by
>> insisting on adding insulation when installing. So yeah, it makes as
>> much sense as many green measures.
>>
>>
> I think we are wedded to the past with water in radiators to heat the
> house.

It's a convenient way to distribute heat around a house. An alternative
would be ducted air, but this required bulky ducts and may be noisy.

> I love my split AC units but I do have enough space outside for a couple
> of outside units.

If you have a lot of rooms it's inconvenient to have separate
heating/cooling appliances unless they are resistive electric heaters
which are expensive to run (as you are converting "high grade" energy
(electricity) directly into "low grade" energy (heat).)

> The only thing that keeps the gas cheaper is the stupid pricing for
> electricity,

More a matter of the Second Law of Thermodynamics and its relation to
the efficiency of Heat Engines (which most power stations are).

--
Max Demian

On 20 Dec 2023 at 12:16:48 GMT, "Max Demian" <max_demian@bigfoot.com> wrote:

> On 20/12/2023 09:04, David Wade wrote:

>> The only thing that keeps the gas cheaper is the stupid pricing for
>> electricity,
>
> More a matter of the Second Law of Thermodynamics and its relation to
> the efficiency of Heat Engines (which most power stations are).

Reality, in other words.

--
"That which can be asserted without evidence, can be dismissed without evidence."
-- Christopher Hitchens

On Wed, 20 Dec 2023 12:16:48 +0000, Max Demian wrote:

> On 20/12/2023 09:04, David Wade wrote:
>> On 20/12/2023 06:32, Animal wrote:
>
>>> Compared to gas, ASHP costs much more upfront, more per therm output,
>>> is noisy, takes up more space, and efficiency takes a dump when it
>>> gets near freezing. The increased cost per output is being hidden by
>>> insisting on adding insulation when installing. So yeah, it makes as
>>> much sense as many green measures.
>>>
>>>
>> I think we are wedded to the past with water in radiators to heat the
>> house.
>
> It's a convenient way to distribute heat around a house. An alternative
> would be ducted air, but this required bulky ducts and may be noisy.
>
>> I love my split AC units but I do have enough space outside for a
>> couple of outside units.
>
> If you have a lot of rooms it's inconvenient to have separate
> heating/cooling appliances unless they are resistive electric heaters
> which are expensive to run (as you are converting "high grade" energy
> (electricity) directly into "low grade" energy (heat).)
>
>> The only thing that keeps the gas cheaper is the stupid pricing for
>> electricity,
>
> More a matter of the Second Law of Thermodynamics and its relation to
> the efficiency of Heat Engines (which most power stations are).

Partly that. Currently, my electricity per kWh is nearly 5 times gas, and
I'm sure power stations are more than 20% efficient!

nib

On 20/12/2023 12:38, Tim Streater wrote:
> On 20 Dec 2023 at 12:16:48 GMT, "Max Demian" <max_demian@bigfoot.com> wrote:
>
>> On 20/12/2023 09:04, David Wade wrote:
>
>>> The only thing that keeps the gas cheaper is the stupid pricing for
>>> electricity,
>>
>> More a matter of the Second Law of Thermodynamics and its relation to
>> the efficiency of Heat Engines (which most power stations are).
>
> Reality, in other words.
>
Reality is for people who can't handle drugs, and left wing/green
politics is for people who can't handle reality...

--
“A leader is best When people barely know he exists. Of a good leader,
who talks little,When his work is done, his aim fulfilled,They will say,
“We did this ourselves.”

― Lao Tzu, Tao Te Ching

On 20/12/2023 12:38, nib wrote:
> On Wed, 20 Dec 2023 12:16:48 +0000, Max Demian wrote:
>
>> On 20/12/2023 09:04, David Wade wrote:
>>> On 20/12/2023 06:32, Animal wrote:
>>
>>>> Compared to gas, ASHP costs much more upfront, more per therm output,
>>>> is noisy, takes up more space, and efficiency takes a dump when it
>>>> gets near freezing. The increased cost per output is being hidden by
>>>> insisting on adding insulation when installing. So yeah, it makes as
>>>> much sense as many green measures.
>>>>
>>>>
>>> I think we are wedded to the past with water in radiators to heat the
>>> house.
>>
>> It's a convenient way to distribute heat around a house. An alternative
>> would be ducted air, but this required bulky ducts and may be noisy.
>>
>>> I love my split AC units but I do have enough space outside for a
>>> couple of outside units.
>>
>> If you have a lot of rooms it's inconvenient to have separate
>> heating/cooling appliances unless they are resistive electric heaters
>> which are expensive to run (as you are converting "high grade" energy
>> (electricity) directly into "low grade" energy (heat).)
>>
>>> The only thing that keeps the gas cheaper is the stupid pricing for
>>> electricity,
>>
>> More a matter of the Second Law of Thermodynamics and its relation to
>> the efficiency of Heat Engines (which most power stations are).
>
> Partly that. Currently, my electricity per kWh is nearly 5 times gas, and
> I'm sure power stations are more than 20% efficient!

A factor of three is more common. (Mine is 3.6 ATM.) I think gas power
stations are about 40% efficient; and then there are the losses in the
power lines.

--
Max Demian