Is it correct to assume a radiator dT=40K for a modern condensing gas
boiler?

70C flow, 50C return so average 60C , nominal room T=20C

Not sure about the flow/return temps...

Oh - and what's the name of those radiator "shelves" that are curved
underneath to flow air into the room?

Couple of locations that have to be under windows, it would be useful to
stop half the hot air going the wrong side of the curtains...

Various google search terms have failed me:

radiator (heat) deflector
radiator (heat) guide

radiator shelf is all conventional shelves...

In article ,
Tim Watts writes:
Is it correct to assume a radiator dT=40K for a modern condensing gas
boiler?

70C flow, 50C return so average 60C , nominal room T=20C

I would make this the worse case.
If you can size radiators for a smaller dT, even better still.
Particularly worth considering with elderly people, where 60C
can still burn without being felt in time in some cases (and
todlers, but they will feel it).

Note that many radiator data sheets specify the power output at
completely unrealistic dT (if you can even find it specified).

Not sure about the flow/return temps...

The system I put in can maintain the house temperature with a
flow/return of 45/35 when just below freezing outside. I didn't
actually intend it to be that good (was aiming slightly higher),
but I'm pleased it is. It also means I can heat the house from
cold very quickly by setting boiler to full power (it can't
actually get the radiators to the max rated flow temperature of
82C, because their output exceeds the boiler's max output
somewhere below 80C.)

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

On 31/01/15 14:22, Andrew Gabriel wrote:
In article ,
Tim Watts writes:
Is it correct to assume a radiator dT=40K for a modern condensing gas
boiler?

70C flow, 50C return so average 60C , nominal room T=20C

I would make this the worse case.
If you can size radiators for a smaller dT, even better still.
Particularly worth considering with elderly people, where 60C
can still burn without being felt in time in some cases (and
todlers, but they will feel it).

Good point. Thank you. I don not mind twiddling the boiler CH water stat
a few times a year to balance it (manual compensation - the WBs do not
seem to have a simple weather compensator without using their fancy
controllers, which I do not want because I'll probably use an RF system).

I'm looking at the electric heating which is being monitored via ZWave
in 4 rooms.

Each of 3 bedrooms (ground floor) and the kitchen/diner have 2kW per
room electric oil rads right now (8kW total).

That is just enough to maintain the status quo at around zero outside
like it is currently.

But if we return from a few days away, it is a struggle to heat the
place from cold - I usually remotely turn all the heaters on about 6
hours in advance.

Kitchen is very space constrained because most of the walls are occupied
- prolly have to have 2 vertical rads, one at each end.

However, I found I can get a really long rad in the hall which will
probably reduce the load on the kitchen rads as currently the kitchen
heat comes back into the hall plus a lobby by the far rear door (2nd
mini hall - that gets a small rad of its own).

Son's room can have a really long thin rad.

Daughter's room is a bit tight - our bedroom is typical.

Although I'm getting the CH fitted, I will be specifying the make/models
of everything as it seems to be a little tricky to balance heat vs space
limitations.

Note that many radiator data sheets specify the power output at
completely unrealistic dT (if you can even find it specified).

I noticed! dT=50K - what is this, steam?

Not sure about the flow/return temps...

The system I put in can maintain the house temperature with a
flow/return of 45/35 when just below freezing outside. I didn't
actually intend it to be that good (was aiming slightly higher),
but I'm pleased it is.

Blimey that is amazingly good. dT=20C? Did you have lots of space for
large surface area rads?

Which make of rad did you use? Best I can find so far are either Kudox
or Stelrad and Kudox do a few in "33" (triple panel) format.

It also means I can heat the house from
cold very quickly by setting boiler to full power (it can't
actually get the radiators to the max rated flow temperature of
82C, because their output exceeds the boiler's max output
somewhere below 80C.)

In message , Tim Watts
writes

Which make of rad did you use? Best I can find so far are either Kudox
or Stelrad and Kudox do a few in "33" (triple panel) format.

I put in 3 Kudox rads last autumn.

I was happy with them. Seem well made and finished and well packed in
cardboard boxes. Even the bracket fixings were decent (decent sized wall
plugs and hex head screws
--
Chris French

In article ,
Tim Watts writes:
On 31/01/15 14:22, Andrew Gabriel wrote:
The system I put in can maintain the house temperature with a
flow/return of 45/35 when just below freezing outside. I didn't
actually intend it to be that good (was aiming slightly higher),
but I'm pleased it is.

Blimey that is amazingly good. dT=20C? Did you have lots of space for
large surface area rads?

Which make of rad did you use? Best I can find so far are either Kudox
or Stelrad and Kudox do a few in "33" (triple panel) format.

They are all Ultraheat. Compact 4 is their standard, and Compact 6
has two extra connections into the bottom of the radiator, which is
useful if you don't want to lose space at the ends for the valves,
and in the case of a triple panel, the TRV fits nicely under the
radiator.

Triple panels are good for large rooms where you don't want to lose
too much wall space - 4 of mine are triple panel Compact 6's. In
one case it's because I could only get a 400mm high radiator under
a recessed low window, the others are all in the larger rooms.

The choice of Ultraheat was because they were made just up the road,
and a local independant plumbers merchant could get me any size
within 3 hours. They had a crap website for years, but it looks
slightly better now. I can't see the Compact 6's on it, but it
never did have the full range in the past. Sometimes they supply a
Compact 6 when you order a Compact 4, which just means you have 2
extra blanking plugs to fit.

These are both triple Compact 6's:
http://www.cucumber.demon.co.uk/radiator.jpg
http://www.cucumber.demon.co.uk/radiator_tp1.jpg

http://www.ultraheat.co.uk/premier-range.html
(Ignore the prices - I think I was charged about half list price
including VAT, although VAT was less then.)

For singles and doubles, I have more recently used Selco (can't
remember what the make is, but they all look very similar), but
that was in a different location where I couldn't so easily get
the Ultraheat's, and the Selco ones were probably cheaper.

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

On 31/01/15 15:45, Andrew Gabriel wrote:
In article ,
Tim Watts writes:
On 31/01/15 14:22, Andrew Gabriel wrote:
The system I put in can maintain the house temperature with a
flow/return of 45/35 when just below freezing outside. I didn't
actually intend it to be that good (was aiming slightly higher),
but I'm pleased it is.

Blimey that is amazingly good. dT=20C? Did you have lots of space for
large surface area rads?

Which make of rad did you use? Best I can find so far are either Kudox
or Stelrad and Kudox do a few in "33" (triple panel) format.

They are all Ultraheat.

That rings a bell from a good while ago - thank you!

Compact 4 is their standard, and Compact 6
has two extra connections into the bottom of the radiator, which is
useful if you don't want to lose space at the ends for the valves,
and in the case of a triple panel, the TRV fits nicely under the
radiator.

Interesting...


Triple panels are good for large rooms where you don't want to lose
too much wall space - 4 of mine are triple panel Compact 6's. In
one case it's because I could only get a 400mm high radiator under
a recessed low window, the others are all in the larger rooms.

I was strongly considering triples for the areas that don't have a long
bit of space. It seems that verticals are not *that* efficient and for
some reason they have insane price tags.

The choice of Ultraheat was because they were made just up the road,
and a local independant plumbers merchant could get me any size
within 3 hours. They had a crap website for years, but it looks
slightly better now. I can't see the Compact 6's on it, but it
never did have the full range in the past. Sometimes they supply a
Compact 6 when you order a Compact 4, which just means you have 2
extra blanking plugs to fit.

These are both triple Compact 6's:
http://www.cucumber.demon.co.uk/radiator.jpg
http://www.cucumber.demon.co.uk/radiator_tp1.jpg

Very smart - I see what you mean about the concealed TRV.

http://www.ultraheat.co.uk/premier-range.html
(Ignore the prices - I think I was charged about half list price
including VAT, although VAT was less then.)

Brilliant - a handy reckoner for price.

For singles and doubles, I have more recently used Selco (can't
remember what the make is, but they all look very similar), but
that was in a different location where I couldn't so easily get
the Ultraheat's, and the Selco ones were probably cheaper.


Many many thanks Andrew - I am compiling a spreadsheet now...

Tim Watts wrote:

70C flow, 50C return so average 60C , nominal room T=20C

If my rooms were all at 20°C, I could live without central heating :-P

On Sat, 31 Jan 2015 12:50:14 -0000, Tim Watts wrote:

Is it correct to assume a radiator dT=40K for a modern condensing gas
boiler?

70C flow, 50C return so average 60C , nominal room T=20C

Not sure about the flow/return temps...

It's OCD to plan radiators. Just shove a radiator in each room where it's convenient to place it and see what happens. The boiler will come on more or less depending on what size you've selected and what the outside temperature is, you don't have to get it anywhere near correct.

--
Worlds most powerful nob enlarger - a space suit with a fly zip

Tim Watts wrote:

http://www.ultraheat.co.uk/premier-range.html
(Ignore the prices - I think I was charged about half list price
including VAT, although VAT was less then.)

Brilliant - a handy reckoner for price.

I bought several from Mr Central Heating last year, all doubles, some
with double fin, others single fin. Delivered from their own vehicle
rather than chucked about by some random courier.

Give them a look for prices ...

http://www.mrcentralheating.co.uk/radiators/compact-radiators

On 31/01/15 16:36, Andy Burns wrote:
Tim Watts wrote:

70C flow, 50C return so average 60C , nominal room T=20C

If my rooms were all at 20°C, I could live without central heating :-P


Valid point - when we are at 20C we will only be balancing the heat loss.

Starting temp back from a holiday might be 10C or 15C if out at work
all day which is when we want it to heat up...

On 31/01/15 16:43, Andy Burns wrote:
Tim Watts wrote:

http://www.ultraheat.co.uk/premier-range.html
(Ignore the prices - I think I was charged about half list price
including VAT, although VAT was less then.)

Brilliant - a handy reckoner for price.

I bought several from Mr Central Heating last year, all doubles, some
with double fin, others single fin. Delivered from their own vehicle
rather than chucked about by some random courier.

Give them a look for prices ...

http://www.mrcentralheating.co.uk/radiators/compact-radiators


Thank you sir! - Bookmarked...

On 31/01/15 15:45, Andrew Gabriel wrote:

The choice of Ultraheat was because they were made just up the road,
and a local independant plumbers merchant could get me any size
within 3 hours. They had a crap website for years, but it looks
slightly better now. I can't see the Compact 6's on it, but it
never did have the full range in the past. Sometimes they supply a
Compact 6 when you order a Compact 4, which just means you have 2
extra blanking plugs to fit.

They certainly seem to have almost every permutation of height, width
and panel/fin count.

The efficiencies seem good too.

Unfortunately their website, which does actually list all the CF models
and their data (in helpful units like watts and not "BTU" (BTU/h?) as
one of their competitors does!) has just died mid way through my calcs.

#AnotherPHPWebsiteBitesTheDust

In article ,
Tim Watts writes:
On 31/01/15 15:45, Andrew Gabriel wrote:

The choice of Ultraheat was because they were made just up the road,
and a local independant plumbers merchant could get me any size
within 3 hours. They had a crap website for years, but it looks
slightly better now. I can't see the Compact 6's on it, but it
never did have the full range in the past. Sometimes they supply a
Compact 6 when you order a Compact 4, which just means you have 2
extra blanking plugs to fit.

They certainly seem to have almost every permutation of height, width
and panel/fin count.

If you can get to mamufacturers rather than stockists, that is often
the case. Hence, using a small plumbers merchant which didn't stock
anything that didn't fit in a tiny shop unit, but could get anything
in hours direct from the manufacturer, can be a good thing - much
bigger choice.

The efficiencies seem good too.

Unfortunately their website, which does actually list all the CF models
and their data (in helpful units like watts and not "BTU" (BTU/h?) as
one of their competitors does!) has just died mid way through my calcs.

It always was ****e, sadly.
Might do better to phone and ask for a pricelist, which has all the
details (and you could check if they still do the Compact 6's is they
are of interest to you).

#AnotherPHPWebsiteBitesTheDust

I've had mine installed for 13 years now. A couple of comments (which
probably apply to all such radiators)...
I haven't painted any of mine - I like the enamel finish, which has
lasted fine on them all, except the one in the bathroom. This is
starting to show some signs of rust along the bottom although not
visible on the front, which I suspect is due to surface condensation
during the summer when the room gets steamy during a shower. Might
be an idea to paint a bathroom one, at least along the bottom.
The second point applies to all makes in the last 20 years which have
blanking plugs - the O-ring seals in blanking plugs don't seal for
anything like as long as proper tapered plugs. Having said that,
the Ultraheat are doing better than a B&Q and a Selco which are much
newer, and the surface for the O-ring to seal against was rough as
hell - I had to pack the thread with PTFE to make it seal there, which
is not ideal as the O-ring plug thread is rather short and parallel,
although it's working now. I much preferred tapered plugs, and I might
replace the blanking plugs with nickel tapered plugs sometime (a bit
more tricky for the one with the bleed valve).

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

On 31/01/2015 12:50, Tim Watts wrote:

Is it correct to assume a radiator dT=40K for a modern condensing gas
boiler?

70C flow, 50C return so average 60C , nominal room T=20C

Not sure about the flow/return temps...

A 20 ish degree drop is fair. The actual flow temp you would probably
assume a maximum of 70 - 75 (the boiler will go higher, but you will
lose much of the gains from the capture of the latent heat of
vapourisation that is the whole raison d'etre of a condensing boiler)



--
Cheers,

John.

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

On 31/01/2015 14:57, Tim Watts wrote:
On 31/01/15 14:22, Andrew Gabriel wrote:
In article ,
Tim Watts writes:
Is it correct to assume a radiator dT=40K for a modern condensing gas
boiler?

70C flow, 50C return so average 60C , nominal room T=20C

I would make this the worse case.
If you can size radiators for a smaller dT, even better still.
Particularly worth considering with elderly people, where 60C
can still burn without being felt in time in some cases (and
todlers, but they will feel it).

Good point. Thank you. I don not mind twiddling the boiler CH water stat
a few times a year to balance it (manual compensation - the WBs do not
seem to have a simple weather compensator without using their fancy
controllers, which I do not want because I'll probably use an RF system).

I'm looking at the electric heating which is being monitored via ZWave
in 4 rooms.

Each of 3 bedrooms (ground floor) and the kitchen/diner have 2kW per
room electric oil rads right now (8kW total).

That is just enough to maintain the status quo at around zero outside
like it is currently.

But if we return from a few days away, it is a struggle to heat the
place from cold - I usually remotely turn all the heaters on about 6
hours in advance.

Kitchen is very space constrained because most of the walls are occupied
- prolly have to have 2 vertical rads, one at each end.

However, I found I can get a really long rad in the hall which will
probably reduce the load on the kitchen rads as currently the kitchen
heat comes back into the hall plus a lobby by the far rear door (2nd
mini hall - that gets a small rad of its own).

Son's room can have a really long thin rad.

Daughter's room is a bit tight - our bedroom is typical.

Although I'm getting the CH fitted, I will be specifying the make/models
of everything as it seems to be a little tricky to balance heat vs space
limitations.

Note that many radiator data sheets specify the power output at
completely unrealistic dT (if you can even find it specified).

I noticed! dT=50K - what is this, steam?

Not sure about the flow/return temps...

The system I put in can maintain the house temperature with a
flow/return of 45/35 when just below freezing outside. I didn't
actually intend it to be that good (was aiming slightly higher),
but I'm pleased it is.

Blimey that is amazingly good. dT=20C? Did you have lots of space for
large surface area rads?

Which make of rad did you use? Best I can find so far are either Kudox
or Stelrad and Kudox do a few in "33" (triple panel) format.

IIRC, I used a few Kudox ones on my most recent rad juggling exercise.
They seem equally well made as any of the better known brands, but were
somewhat cheaper.

(note their figures specify the Tdelata as the difference between flow
temperatur and ambient - rather than between flow and return)

http://www.kudox.com/Files/Website%2...cal%20Data.pdf

--
Cheers,

John.

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

On 31/01/2015 16:36, Andy Burns wrote:
Tim Watts wrote:

70C flow, 50C return so average 60C , nominal room T=20C

If my rooms were all at 20°C, I could live without central heating :-P

Although if the heating is doing its job, that is the room temp (give or
take a bit) they will be trying to maintain hopefully ;-)


--
Cheers,

John.

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

On 31/01/2015 16:43, Uncle Peter wrote:
On Sat, 31 Jan 2015 12:50:14 -0000, Tim Watts wrote:

Is it correct to assume a radiator dT=40K for a modern condensing gas
boiler?

70C flow, 50C return so average 60C , nominal room T=20C

Not sure about the flow/return temps...

It's OCD to plan radiators. Just shove a radiator in each room where
it's convenient to place it and see what happens. The boiler will come
on more or less depending on what size you've selected and what the
outside temperature is, you don't have to get it anywhere near correct.

You should be a plumber... or "heating engineer". You know, the kind of
folks that explain why we DIY.


--
Cheers,

John.

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

On Sun, 01 Feb 2015 23:22:41 -0000, John Rumm wrote:

On 31/01/2015 16:43, Uncle Peter wrote:
On Sat, 31 Jan 2015 12:50:14 -0000, Tim Watts wrote:

Is it correct to assume a radiator dT=40K for a modern condensing gas
boiler?

70C flow, 50C return so average 60C , nominal room T=20C

Not sure about the flow/return temps...

It's OCD to plan radiators. Just shove a radiator in each room where
it's convenient to place it and see what happens. The boiler will come
on more or less depending on what size you've selected and what the
outside temperature is, you don't have to get it anywhere near correct.

You should be a plumber... or "heating engineer". You know, the kind of
folks that explain why we DIY.

We diy to save money. And to avoid all this expensive ****ing about planning ****.

--
Hello: A shout to attract attention, first recorded 1588. Popularity as a greeting coincides with use of the telephone, where it won out over Alexander Graham Bell's suggestion, ahoy.

On 01/02/15 23:15, John Rumm wrote:
On 31/01/2015 14:57, Tim Watts wrote:
On 31/01/15 14:22, Andrew Gabriel wrote:

IIRC, I used a few Kudox ones on my most recent rad juggling exercise.
They seem equally well made as any of the better known brands, but were
somewhat cheaper.

Thanks John,

(note their figures specify the Tdelata as the difference between flow
temperatur and ambient - rather than between flow and return)

http://www.kudox.com/Files/Website%2...cal%20Data.pdf

That's what I assumed - as deltaT-Flow/Return is only useful if you also
know the flow rate, which noone does

I have been looking at my ZWave power measurements. Quite interesting...

To sustain at 20-21C with 2-3C outside, averager power over a day, no
heating at night:

Our bedroom 1.5kW (contributes to hall, 2 outside walls, bay window)
Daughter's bedroom - 400W (one short outside wall)
Son's bedroom - 600W (2 outside walls, smaller windows)
Kitchen 1.5kw (contributes to hall and rear lobby)
- Also fire running in the kitchen, say 2kW more.

Total load about 6kW inc fire on an exceptionally cold day.

Conservatory - took a 2kW heater there plus power meter and temp sensor.

Started at 9C, 2kW flat out took it to 16C after 3 hours where it
plateaued. Turned heater off - it fell like a stone, 13C in one hour.


So far I've managed to spec rads with a total output of 12.4kW at
deltaT=30C (ambient 20C) so I guess 55/45C ?

At deltaT=40C the total output would be 17kW and according to your
figures that is still running in condensing mode.


The conservatory would have UFH specced at about 2kW but in winter we'd
use it just to keep the edge off the cold - say 12C and have a Myson fan
convector for rapid boost - these seem rather good - their bigger wall
model can shove out 3.8kW in Boost mode at deltaT=40C


Now, these are using the biggest radiators I can comfortably fit in -
Kitchen is awkward as I only have 2 500mm long spaces, but triple panel
rads seem to be better than verticals.

On 01/02/15 23:22, John Rumm wrote:
On 31/01/2015 16:43, Uncle Peter wrote:
On Sat, 31 Jan 2015 12:50:14 -0000, Tim Watts
wrote:

Is it correct to assume a radiator dT=40K for a modern condensing gas
boiler?

70C flow, 50C return so average 60C , nominal room T=20C

Not sure about the flow/return temps...

It's OCD to plan radiators. Just shove a radiator in each room where
it's convenient to place it and see what happens. The boiler will come
on more or less depending on what size you've selected and what the
outside temperature is, you don't have to get it anywhere near correct.

Uncle Peter is being a wally.

CH installations is one of the biggest expenses so if you don't plan,
you're a fool.

You should be a plumber... or "heating engineer". You know, the kind of
folks that explain why we DIY.

Although I'm subbing this out I don't trust any plumbers with the design
so I'm specifying stuff

Tim Watts wrote:

these are using the biggest radiators I can comfortably fit in -
Kitchen is awkward as I only have 2 500mm long spaces, but triple panel
rads seem to be better than verticals.

If you're cutting it fine on heat output, are you allowing for the
"book" figures for the radiators being quoted for TBSE plumbing, with
slightly lower output (5 to 10%) when plumbed BBOE?

In article ,
Andy Burns writes:
Tim Watts wrote:

these are using the biggest radiators I can comfortably fit in -
Kitchen is awkward as I only have 2 500mm long spaces, but triple panel
rads seem to be better than verticals.

If you're cutting it fine on heat output, are you allowing for the
"book" figures for the radiators being quoted for TBSE plumbing, with
slightly lower output (5 to 10%) when plumbed BBOE?

Doesn't make any difference for a pumped system, and he's not
going to be installing a convection circulating system.

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

On 02/02/15 09:19, Andy Burns wrote:
Tim Watts wrote:

these are using the biggest radiators I can comfortably fit in -
Kitchen is awkward as I only have 2 500mm long spaces, but triple panel
rads seem to be better than verticals.

If you're cutting it fine on heat output, are you allowing for the
"book" figures for the radiators being quoted for TBSE plumbing, with
slightly lower output (5 to 10%) when plumbed BBOE?


TBSE
BBOE?

You mean because of heat drops in the pipes?

Overall I have more than enough - it is just the kitchen and rear lobby
are hard to get a lot of power into as walls are very cluttered.

Myson blower in the lobby remains an option though. Will not be allowed
one in the kitchen as SWMBO will veto it for being noisy.

She wanted to veto the conservatory one, but I said it was the only
practical way to boost the heat there at short notice as it is of course
very lossy. The UFH there is more for spring/autumn and to keep the
chill off in winter.

Talking of which, I should probably look at antifreeze in the CH circuit
as well as inhibitor.

On 02/02/15 10:04, Andrew Gabriel wrote:
In article ,
Andy Burns writes:
Tim Watts wrote:

these are using the biggest radiators I can comfortably fit in -
Kitchen is awkward as I only have 2 500mm long spaces, but triple panel
rads seem to be better than verticals.

If you're cutting it fine on heat output, are you allowing for the
"book" figures for the radiators being quoted for TBSE plumbing, with
slightly lower output (5 to 10%) when plumbed BBOE?

Doesn't make any difference for a pumped system, and he's not
going to be installing a convection circulating system.


Oh...

Tim Watts wrote:
On 01/02/15 23:15, John Rumm wrote:
On 31/01/2015 14:57, Tim Watts wrote:
On 31/01/15 14:22, Andrew Gabriel wrote:

IIRC, I used a few Kudox ones on my most recent rad juggling exercise.
They seem equally well made as any of the better known brands, but were
somewhat cheaper.

Thanks John,

(note their figures specify the Tdelata as the difference between flow
temperatur and ambient - rather than between flow and return)

http://www.kudox.com/Files/Website%2...cal%20Data.pdf


That's what I assumed - as deltaT-Flow/Return is only useful if you also
know the flow rate, which noone does

I have been looking at my ZWave power measurements. Quite interesting...

To sustain at 20-21C with 2-3C outside, averager power over a day, no
heating at night:

Our bedroom 1.5kW (contributes to hall, 2 outside walls, bay window)
Daughter's bedroom - 400W (one short outside wall)
Son's bedroom - 600W (2 outside walls, smaller windows)
Kitchen 1.5kw (contributes to hall and rear lobby)
- Also fire running in the kitchen, say 2kW more.

Total load about 6kW inc fire on an exceptionally cold day.

Conservatory - took a 2kW heater there plus power meter and temp sensor.

Started at 9C, 2kW flat out took it to 16C after 3 hours where it
plateaued. Turned heater off - it fell like a stone, 13C in one hour.


So far I've managed to spec rads with a total output of 12.4kW at
deltaT=30C (ambient 20C) so I guess 55/45C ?

At deltaT=40C the total output would be 17kW and according to your
figures that is still running in condensing mode.


The conservatory would have UFH specced at about 2kW but in winter we'd
use it just to keep the edge off the cold - say 12C and have a Myson fan
convector for rapid boost - these seem rather good - their bigger wall
model can shove out 3.8kW in Boost mode at deltaT=40C


Now, these are using the biggest radiators I can comfortably fit in -
Kitchen is awkward as I only have 2 500mm long spaces, but triple panel
rads seem to be better than verticals.



Sounds like you'd be better off putting in heat pumps.

On 02/02/15 10:30, Capitol wrote:

Sounds like you'd be better off putting in heat pumps.

Why? That would make it worse with respect to CH flow temps.

Also - I did look at air source heat pumps. The economics are laughable.

They look good initially - with a 100% heat gain over the electrical
power input. Until you notice that that is peak rate electricity and gas
round our way is 1/3 the price of electricity kW for kW.

Tim Watts wrote:

TBSE
BBOE?

flow at _T_op with return at _B_ottom of _S_ame _E_nd, flow at _B_ottom
and return at _B_ottom of _O_pposite _E_nds, also flow at _T_op and
return at _B_ottom of _O_pposite _E_nds.

You mean because of heat drops in the pipes?

The BSEN 442 spec states that is how rads are plumbed for testing,
various sites give different de-rating factors for other plumbing types,
but I hadn't picked-up that this was not* relevant to pumped systems.

[*] Can't see how it's /totally/ irrelevant, perhaps it's negligible though.

In article ,
Andy Burns writes:
Tim Watts wrote:

TBSE
BBOE?

flow at _T_op with return at _B_ottom of _S_ame _E_nd, flow at _B_ottom
and return at _B_ottom of _O_pposite _E_nds, also flow at _T_op and
return at _B_ottom of _O_pposite _E_nds.

You mean because of heat drops in the pipes?

The BSEN 442 spec states that is how rads are plumbed for testing,
various sites give different de-rating factors for other plumbing types,
but I hadn't picked-up that this was not* relevant to pumped systems.


[*] Can't see how it's /totally/ irrelevant, perhaps it's negligible though.

If you search out infra-red pictures of radiators, you will see the
hot inlet all rises to the top in the first channel because the
convection effect inside the radiator is very strong. It therefore
doesn't make any significant difference in the radiator if you pipe
the inlet to the top or the bottom - the hot water goes straight to
the top anyway, and then uniformly descends the whole rest of the
radiator, making for a pretty much perfect contra-flow heat exchanger
with the convecting air.

If you run a pipe to the top, you will get a tiny bit extra heat
output from that pipe (but not as much as making the radiator wider
to take up the space of the pipe).

The only important thing is that the outlet/return must be at the
bottom.

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

In article ,
Tim Watts writes:
On 02/02/15 10:30, Capitol wrote:

Sounds like you'd be better off putting in heat pumps.

Why? That would make it worse with respect to CH flow temps.

Also - I did look at air source heat pumps. The economics are laughable.

They look good initially - with a 100% heat gain over the electrical
power input. Until you notice that that is peak rate electricity and gas
round our way is 1/3 the price of electricity kW for kW.

I use one in my main room (which is also my office at one end)
when I'm working at home, and don't need to heat the whole house.

Originally bought it for cooling in the summer, but it gets used
only for a few days for cooling, but much more for heating.

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

Andrew Gabriel wrote:

Andy Burns writes:

Can't see how it's /totally/ irrelevant, perhaps it's negligible though.

If you search out infra-red pictures of radiators, you will see the
hot inlet all rises to the top in the first channel because the
convection effect inside the radiator is very strong.

Searching for "radiator and FLIR" seems to find better results than
"radiator and infrared", but these images seem pretty convincing

http://signalsurveyors.co.uk/2014/08/04/117

The only important thing is that the outlet/return must be at the
bottom.

Yes, I can see BTSE being a really bad idea!

On Mon, 02 Feb 2015 08:47:12 -0000, Tim Watts wrote:

On 01/02/15 23:22, John Rumm wrote:
On 31/01/2015 16:43, Uncle Peter wrote:
On Sat, 31 Jan 2015 12:50:14 -0000, Tim Watts
wrote:

Is it correct to assume a radiator dT=40K for a modern condensing gas
boiler?

70C flow, 50C return so average 60C , nominal room T=20C

Not sure about the flow/return temps...

It's OCD to plan radiators. Just shove a radiator in each room where
it's convenient to place it and see what happens. The boiler will come
on more or less depending on what size you've selected and what the
outside temperature is, you don't have to get it anywhere near correct.

Uncle Peter is being a wally.

CH installations is one of the biggest expenses so if you don't plan,
you're a fool.

You somehow think you can make it drastically cheaper by planning? Just buy a radiator for each room, a load of pipe, and a boiler. Fit it yourself, it's not rocket surgery.

--
A fat girl served me in McDonald's at lunchtime. She said "sorry about the wait". I said, "Don't worry, you'll find a way to lose it eventually"

How do you work out what size boiler you need without some planning?In
article , Uncle Peter wrote:
On Mon, 02 Feb 2015 08:47:12 -0000, Tim Watts
wrote:

On 01/02/15 23:22, John Rumm wrote:
On 31/01/2015 16:43, Uncle Peter wrote:
On Sat, 31 Jan 2015 12:50:14 -0000, Tim Watts
wrote:

Is it correct to assume a radiator dT=40K for a modern condensing
gas boiler?

70C flow, 50C return so average 60C , nominal room T=20C

Not sure about the flow/return temps...

It's OCD to plan radiators. Just shove a radiator in each room where
it's convenient to place it and see what happens. The boiler will
come on more or less depending on what size you've selected and what
the outside temperature is, you don't have to get it anywhere near
correct.

Uncle Peter is being a wally.

CH installations is one of the biggest expenses so if you don't plan,
you're a fool.

You somehow think you can make it drastically cheaper by planning? Just
buy a radiator for each room, a load of pipe, and a boiler. Fit it
yourself, it's not rocket surgery.

How do know what size of boiler to buy without some form of planning?

--
From KT24 in Surrey

Using a RISC OS computer running v5.18

On 02/02/15 11:24, Andrew Gabriel wrote:
In article ,
Tim Watts writes:
On 02/02/15 10:30, Capitol wrote:

Sounds like you'd be better off putting in heat pumps.

Why? That would make it worse with respect to CH flow temps.

Also - I did look at air source heat pumps. The economics are laughable.

They look good initially - with a 100% heat gain over the electrical
power input. Until you notice that that is peak rate electricity and gas
round our way is 1/3 the price of electricity kW for kW.

I use one in my main room (which is also my office at one end)
when I'm working at home, and don't need to heat the whole house.

Originally bought it for cooling in the summer, but it gets used
only for a few days for cooling, but much more for heating.


I agree if it has the purpose of cooling, then it is useful on a single
room basis.

My criticism was levelled at whole house systems.

On 02/02/2015 08:47, Tim Watts wrote:
On 01/02/15 23:22, John Rumm wrote:
On 31/01/2015 16:43, Uncle Peter wrote:
On Sat, 31 Jan 2015 12:50:14 -0000, Tim Watts
wrote:

Is it correct to assume a radiator dT=40K for a modern condensing gas
boiler?

70C flow, 50C return so average 60C , nominal room T=20C

Not sure about the flow/return temps...

It's OCD to plan radiators. Just shove a radiator in each room where
it's convenient to place it and see what happens. The boiler will come
on more or less depending on what size you've selected and what the
outside temperature is, you don't have to get it anywhere near correct.

Uncle Peter is being a wally.

CH installations is one of the biggest expenses so if you don't plan,
you're a fool.


I'd agree, but IME I'd overspec as much as possible subject to space,
appearance, pipe/boiler and common sense.

One reason being it'll get the room up to temperature quicker. The other
being that calculations can be defeated by real world use. Opening doors
and windows a favourite round these parts ;-)


--
Cheers, Rob

On Mon, 02 Feb 2015 13:27:33 -0000, RJH wrote:

On 02/02/2015 08:47, Tim Watts wrote:
On 01/02/15 23:22, John Rumm wrote:
On 31/01/2015 16:43, Uncle Peter wrote:
On Sat, 31 Jan 2015 12:50:14 -0000, Tim Watts
wrote:

Is it correct to assume a radiator dT=40K for a modern condensing gas
boiler?

70C flow, 50C return so average 60C , nominal room T=20C

Not sure about the flow/return temps...

It's OCD to plan radiators. Just shove a radiator in each room where
it's convenient to place it and see what happens. The boiler will come
on more or less depending on what size you've selected and what the
outside temperature is, you don't have to get it anywhere near correct.

Uncle Peter is being a wally.

CH installations is one of the biggest expenses so if you don't plan,
you're a fool.

I'd agree, but IME I'd overspec as much as possible subject to space,
appearance, pipe/boiler and common sense.

One reason being it'll get the room up to temperature quicker.

Why let it get so far below temperature in the first place?

The other
being that calculations can be defeated by real world use. Opening doors
and windows a favourite round these parts ;-)

Did someone fart?

--
Money can't buy you true love.
It does however put you in a good bargaining position.

On Mon, 02 Feb 2015 12:28:37 -0000, charles wrote:


How do you work out what size boiler you need without some planning?In
article , Uncle Peter wrote:
On Mon, 02 Feb 2015 08:47:12 -0000, Tim Watts
wrote:

On 01/02/15 23:22, John Rumm wrote:
On 31/01/2015 16:43, Uncle Peter wrote:
On Sat, 31 Jan 2015 12:50:14 -0000, Tim Watts
wrote:

Is it correct to assume a radiator dT=40K for a modern condensing
gas boiler?

70C flow, 50C return so average 60C , nominal room T=20C

Not sure about the flow/return temps...

It's OCD to plan radiators. Just shove a radiator in each room where
it's convenient to place it and see what happens. The boiler will
come on more or less depending on what size you've selected and what
the outside temperature is, you don't have to get it anywhere near
correct.

Uncle Peter is being a wally.

CH installations is one of the biggest expenses so if you don't plan,
you're a fool.

You somehow think you can make it drastically cheaper by planning? Just
buy a radiator for each room, a load of pipe, and a boiler. Fit it
yourself, it's not rocket surgery.

How do know what size of boiler to buy without some form of planning?

Every house I've seen has a boiler that can handle about 5 times what it's doing, so I'd buy the cheapest smallest one. The only point in buying a bigger one I can see is that it wouldn't be worked do hard, and would last longer, so that's not about speccing it, that's about how much it costs per size and what money you want to shell out now.

--
Peter is listening to "Who's the best - DJ Mad Dog feat. Tommyknocker"

On 31/01/2015 16:43, Uncle Peter wrote:

It's OCD to plan radiators. Just shove a radiator in each room where
it's convenient to place it and see what happens. The boiler will come
on more or less depending on what size you've selected and what the
outside temperature is, you don't have to get it anywhere near correct.

As much as I'd like to disagree due to me being anal about such stuff,
I've found doing all the calculations and factoring outside walls,
windows, insulation, ceiling height and everything else to a precise
degree has always given me radiators with a capacity vastly greater than
required and taking up much more wall space than they ever need to.

With this in mind, when I did the radiators for the downstairs
bedrooms/hall I simply got the best sizes to fit in the gap under the
window and added some shiny panels to the walls before fitting rads.
(http://www.heatkeeper.co.uk/) (because they were pretty cheap and
potentially afforded a real benefit)

My calculation would have had massive radiators because I'm running a
max. flow of 55 degrees however even at such a low temp, with
un-insulated floors the aesthetically attractive (to fit the space
rather than formula calculated) radiators do the job brilliantly. When
the outside temp is higher than 3 degrees causing flow temp. to be even
lower than 55 the rad's run to perfection even in the north side bedroom
with 2 x outside walls.

So, from personal experience with 3 completely different properties from
a 60's semi, a Victorian flat above the shop to a 70's upsidedown
detached with half UFH and half radiators I can wholeheartedly say that
pedantic calculations serve at best to give you a grossly over-sized
radiator that will heat a room admirably with a fraction of the designed
flow temp when it's -20 outside.

Having said all that I'd still go through the whole pedantic
calculations to satisfy peace of mind, then be happy knowing I can
significantly down-size the radiators without worrying about things.

If they do struggle in the coldest of cold winters you can always crank
up the boiler to 80 degrees for a week or to to compensate and forget
about saving a few pennies from condensing.

On 02/02/2015 17:23, Uncle Peter wrote:

One reason being it'll get the room up to temperature quicker.

Why let it get so far below temperature in the first place?

Once more I have to agree...
If your loft is adequately insulated (and I know ALL about the
difference between full insulation and no insulation!) The rooms
shouldn't drop more than a few degrees at the very most between morning
"off" and evening "on" times. (mine never drop below 19 so I have
set-back on each room set to 18.5

You can simply kick the heating to come on earlier if it's not coming up
to temp. by a certain time. Same energy input excepting for a bit more
electricity to run the CH pump a little longer.

And... in the case of my UFH it's actually far more comfortable to have
the floor being "on" all the time by not quite getting to cut-off temp
compared to it going "off" (over-heating) and waiting for ambient temp
to finish rising before dropping enough for it to kick into life again.



Just more of my casual observations over the years.

On Mon, 02 Feb 2015 18:47:17 -0000, www.GymRatZ.co.uk wrote:

On 02/02/2015 17:23, Uncle Peter wrote:

One reason being it'll get the room up to temperature quicker.

Why let it get so far below temperature in the first place?

Once more I have to agree...
If your loft is adequately insulated (and I know ALL about the
difference between full insulation and no insulation!) The rooms
shouldn't drop more than a few degrees at the very most between morning
"off" and evening "on" times. (mine never drop below 19 so I have
set-back on each room set to 18.5

You can simply kick the heating to come on earlier if it's not coming up
to temp. by a certain time. Same energy input excepting for a bit more
electricity to run the CH pump a little longer.

And... in the case of my UFH it's actually far more comfortable to have
the floor being "on" all the time by not quite getting to cut-off temp
compared to it going "off" (over-heating) and waiting for ambient temp
to finish rising before dropping enough for it to kick into life again.



Just more of my casual observations over the years.

Why make things so complicated? I just set my heating to one temperature and leave it there 24/7. I doubt you save much by allowing the house to cool a little then reheat it again.

--
Give a man a fish and he will eat for a day; teach a man to fish and he will eat for a lifetime; give a man religion and he will die praying for a fish