At present I have a system which has individual heating controls on all
radiators apart from the one in the hall which is not controlled
individually.
There is a temperature control on the boiler
What is the best system for CH Control ?
Many years ago I had a system where there was a central thermostat control
with no controls on the radiators
Is it possible or desirable to have individual controls on the radiators but
in addition have a central thermostatic control as well
Blair

On 24/12/2011 15:05, bm wrote:
At present I have a system which has individual heating controls on all
radiators apart from the one in the hall which is not controlled
individually.
There is a temperature control on the boiler
What is the best system for CH Control ?
Many years ago I had a system where there was a central thermostat control
with no controls on the radiators
Is it possible or desirable to have individual controls on the radiators but
in addition have a central thermostatic control as well

Ideally you should have the rad valve setup that you have, plus a main
thermostat in the hall. That allows the boiler to be shut off once the
house is up to temperature. With your setup as it currently is, all the
time the programmer has the heating "on", the boiler will have to keep
running and cycle on its own internal water temperature stat, even when
the house is already warm enough.


--
Cheers,

John.

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

On 24/12/2011 15:05, bm wrote:
At present I have a system which has individual heating controls on all
radiators apart from the one in the hall which is not controlled
individually.
There is a temperature control on the boiler
What is the best system for CH Control ?
Many years ago I had a system where there was a central thermostat control
with no controls on the radiators
Is it possible or desirable to have individual controls on the radiators but
in addition have a central thermostatic control as well
Blair


As said, ideally you need a room stat as well. It's not too hard to add
one, especially the wireless type. Do you have combi or heat only boiler?

--
David

On Sat, 24 Dec 2011 15:05:03 -0000, "bm" wrote:

At present I have a system which has individual heating controls on all
radiators apart from the one in the hall which is not controlled
individually.

That sounds weird as that is the ideal layout for a good system but
the installer seems to have missed out on the final bit, the hall
thermostat. As the hall rad has no thermostat, they obviously intended
to have one but didn't for some reason.

In message , John
Rumm wrote

Ideally you should have the rad valve setup that you have, plus a main
thermostat in the hall.

And if you want to save money put the thermostat in the room you use
most for sitting down. Don't have a thermostatic radiator valve on
radiators in the same room as the room thermostat.

If you get a wireless room thermostat you can experiment into the best
position within the house for fitting.
--
Alan
news2009 {at} admac {dot} myzen {dot} co {dot} uk

"gremlin_95" wrote in message
...
On 24/12/2011 15:05, bm wrote:
At present I have a system which has individual heating controls on all
radiators apart from the one in the hall which is not controlled
individually.
There is a temperature control on the boiler
What is the best system for CH Control ?
Many years ago I had a system where there was a central thermostat
control
with no controls on the radiators
Is it possible or desirable to have individual controls on the radiators
but
in addition have a central thermostatic control as well
Blair


As said, ideally you need a room stat as well. It's not too hard to add
one, especially the wireless type. Do you have combi or heat only boiler?

--
David
I do not have a combi boiler My boiler heats the water in the storage tank
and the central heating.
My wife wanted a storage tank which was a useful hot cupboard for drying
clothes etc.
In addition my experience with a combi boiler is that unless the hot runs
slow the water will not be warm enough. so it takes a long time to fill a
bath
Your idea of a wireless thermosat sounds the answer as wiring an existing
house would be difficult
Many thanks
Blair

"Ericp" wrote in message
news
On Sat, 24 Dec 2011 15:05:03 -0000, "bm" wrote:

At present I have a system which has individual heating controls on all
radiators apart from the one in the hall which is not controlled
individually.

That sounds weird as that is the ideal layout for a good system but
the installer seems to have missed out on the final bit, the hall
thermostat. As the hall rad has no thermostat, they obviously intended
to have one but didn't for some reason.

I understand that this was for safety reasons. I was told that there must be
at least one which is on all the time
Blair

"John Rumm" wrote in message
o.uk...
On 24/12/2011 15:05, bm wrote:
At present I have a system which has individual heating controls on all
radiators apart from the one in the hall which is not controlled
individually.
There is a temperature control on the boiler
What is the best system for CH Control ?
Many years ago I had a system where there was a central thermostat
control
with no controls on the radiators
Is it possible or desirable to have individual controls on the radiators
but
in addition have a central thermostatic control as well

Ideally you should have the rad valve setup that you have, plus a main
thermostat in the hall. That allows the boiler to be shut off once the
house is up to temperature. With your setup as it currently is, all the
time the programmer has the heating "on", the boiler will have to keep
running and cycle on its own internal water temperature stat, even when
the house is already warm enough.


--
Cheers,

John.

Many thanks for you help
Blair

In message , bm writes

"gremlin_95" wrote in message
...
On 24/12/2011 15:05, bm wrote:
At present I have a system which has individual heating controls on all
radiators apart from the one in the hall which is not controlled
individually.
There is a temperature control on the boiler
What is the best system for CH Control ?
Many years ago I had a system where there was a central thermostat
control
with no controls on the radiators
Is it possible or desirable to have individual controls on the radiators
but
in addition have a central thermostatic control as well
Blair


As said, ideally you need a room stat as well. It's not too hard to add
one, especially the wireless type. Do you have combi or heat only boiler?

--
David
I do not have a combi boiler My boiler heats the water in the storage tank
and the central heating.
My wife wanted a storage tank which was a useful hot cupboard for drying
clothes etc.
In addition my experience with a combi boiler is that unless the hot runs
slow the water will not be warm enough. so it takes a long time to fill a
bath

Then your boiler is under spec'd



--
geoff

"geoff" wrote in message
...
In message , bm writes

"gremlin_95" wrote in message
...
On 24/12/2011 15:05, bm wrote:
At present I have a system which has individual heating controls on all
radiators apart from the one in the hall which is not controlled
individually.
There is a temperature control on the boiler
What is the best system for CH Control ?
Many years ago I had a system where there was a central thermostat
control
with no controls on the radiators
Is it possible or desirable to have individual controls on the
radiators
but
in addition have a central thermostatic control as well
Blair


As said, ideally you need a room stat as well. It's not too hard to add
one, especially the wireless type. Do you have combi or heat only
boiler?

--
David
I do not have a combi boiler My boiler heats the water in the storage tank
and the central heating.
My wife wanted a storage tank which was a useful hot cupboard for drying
clothes etc.
In addition my experience with a combi boiler is that unless the hot runs
slow the water will not be warm enough. so it takes a long time to fill a
bath

Then your boiler is under spec'd



--
geoff
I should also have added that it is a condensing boiler
Blair

bm wrote:

Your idea of a wireless thermosat sounds the answer as wiring an existing
house would be difficult

Honeywell for wireless stats.
They are the only makers that use the 800+MHz band (800mHz?), so dont
get interference from other wireless devices. They are also 'paired' at
the factory, so should be plug and play.

I would go for one of the programmable ones, probably the CM 927, then
you can set different temperatures for different times.
They are £20 - 30 more than other makes, but worth it for the 'no
hassle' of getting the wireless to work. I've fitted 2 Salus room stats,
and both needed return visits, as the wireless was being interuppted by
some other wireless device, so always fit Honeywell now.

It will also make a big difference to your heating bill - I couldnt
beleive how little the boiler was burning when I fitted my own,
previously, like yours, I had my boiler on its internal stat, and it
would be on all day burning away, i've been in this afternoon, and it
has only come on 3 or 4 times in the last hour, with the temperature a
comfortable 20 degrees. I think it helps with balancing out the house
temperature too, if one room is too hot, turn it down, and once
balanced, the system will be efficient.
You'll get your money back in reduced gas bills after a year or less by
fitting a room stat.

Alan.

--
To reply by e-mail, change the ' + ' to 'plus'.

On 24/12/2011 16:24, Alan wrote:
In message , John
Rumm wrote

Ideally you should have the rad valve setup that you have, plus a main
thermostat in the hall.

And if you want to save money put the thermostat in the room you use
most for sitting down. Don't have a thermostatic radiator valve on
radiators in the same room as the room thermostat.

If you get a wireless room thermostat you can experiment into the best
position within the house for fitting.

and you can always take the thermostatic head off the rad in that room -
with most that will have the effect of leaving the rad full on. (make
sure the rads have been properly balanced however, rather than relying
on the TRV to bodge it for you)

--
Cheers,

John.

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

On 24/12/2011 17:03, bm wrote:
wrote in message
...
In , writes

wrote in message
...
On 24/12/2011 15:05, bm wrote:
At present I have a system which has individual heating controls on all
radiators apart from the one in the hall which is not controlled
individually.
There is a temperature control on the boiler
What is the best system for CH Control ?
Many years ago I had a system where there was a central thermostat
control
with no controls on the radiators
Is it possible or desirable to have individual controls on the
radiators
but
in addition have a central thermostatic control as well
Blair


As said, ideally you need a room stat as well. It's not too hard to add
one, especially the wireless type. Do you have combi or heat only
boiler?

--
David
I do not have a combi boiler My boiler heats the water in the storage tank
and the central heating.
My wife wanted a storage tank which was a useful hot cupboard for drying
clothes etc.
In addition my experience with a combi boiler is that unless the hot runs
slow the water will not be warm enough. so it takes a long time to fill a
bath

Then your boiler is under spec'd



--
geoff

I should also have added that it is a condensing boiler
Blair

As are pretty much all you buy these days... I think Geoff was
commenting on combis and slow water delivery. You need a very powerful
one to be able to get a reasonable flow of hot water out of it. With a
storage system like yours then you can specify a lower powered boiler
for running the rads, and heating the cylinder, since it does not need
to do the hot water on demand, but can take its time over it!


--
Cheers,

John.

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

On 24/12/2011 16:33, bm wrote:
wrote in message
news
On Sat, 24 Dec 2011 15:05:03 -0000, wrote:

At present I have a system which has individual heating controls on all
radiators apart from the one in the hall which is not controlled
individually.

That sounds weird as that is the ideal layout for a good system but
the installer seems to have missed out on the final bit, the hall
thermostat. As the hall rad has no thermostat, they obviously intended
to have one but didn't for some reason.

I understand that this was for safety reasons. I was told that there must be
at least one which is on all the time

That can be true - depends on other factors. You typically need some
form of "bypass" to allow the pump to keep circulating water through the
boiler. If all the rads had TMVs then once the house is warm and they
all shut off, the water flow would be blocked. One solution to this is
leaving at least one rad "open" (with lockshield valves at both ends so
that its difficult to accidentally turn it "off"). Other options include
an automatic bypass valve (a pressure sensitive affair that only passes
water when there no other path through the system), or a boiler with an
internal bypass capability.

Alas there seem to be lots of plumbers out there who either do not
understand the significance of proper controls, or are penny pinching by
not fitting them.


--
Cheers,

John.

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

In message , John
Rumm writes
On 24/12/2011 17:03, bm wrote:
wrote in message
...
In , writes

wrote in message
...
On 24/12/2011 15:05, bm wrote:
At present I have a system which has individual heating controls on all
radiators apart from the one in the hall which is not controlled
individually.
There is a temperature control on the boiler
What is the best system for CH Control ?
Many years ago I had a system where there was a central thermostat
control
with no controls on the radiators
Is it possible or desirable to have individual controls on the
radiators
but
in addition have a central thermostatic control as well
Blair


As said, ideally you need a room stat as well. It's not too hard to add
one, especially the wireless type. Do you have combi or heat only
boiler?

--
David
I do not have a combi boiler My boiler heats the water in the storage tank
and the central heating.
My wife wanted a storage tank which was a useful hot cupboard for drying
clothes etc.
In addition my experience with a combi boiler is that unless the hot runs
slow the water will not be warm enough. so it takes a long time to fill a
bath

Then your boiler is under spec'd



--
geoff

I should also have added that it is a condensing boiler
Blair

As are pretty much all you buy these days... I think Geoff was
commenting on combis and slow water delivery. You need a very powerful
one to be able to get a reasonable flow of hot water out of it.

Not really, mine is a 28kW which is fairly standard nowadays, and it
delivers sufficient flow rate.


Combis suffer somewhat from a historical bad press

With a storage system like yours then you can specify a lower powered
boiler for running the rads, and heating the cylinder, since it does
not need to do the hot water on demand, but can take its time over it!



--
geoff

On 24/12/2011 17:32, A.Lee wrote:
wrote:

Your idea of a wireless thermosat sounds the answer as wiring an existing
house would be difficult
Honeywell for wireless stats.
They are the only makers that use the 800+MHz band (800mHz?), so dont
get interference from other wireless devices. They are also 'paired' at
the factory, so should be plug and play.

I would go for one of the programmable ones, probably the CM 927, then
you can set different temperatures for different times.
They are £20 - 30 more than other makes, but worth it for the 'no
hassle' of getting the wireless to work. I've fitted 2 Salus room stats,
and both needed return visits, as the wireless was being interuppted by
some other wireless device, so always fit Honeywell now.

It will also make a big difference to your heating bill - I couldnt
beleive how little the boiler was burning when I fitted my own,
previously, like yours, I had my boiler on its internal stat, and it
would be on all day burning away, i've been in this afternoon, and it
has only come on 3 or 4 times in the last hour, with the temperature a
comfortable 20 degrees. I think it helps with balancing out the house
temperature too, if one room is too hot, turn it down, and once
balanced, the system will be efficient.
You'll get your money back in reduced gas bills after a year or less by
fitting a room stat.

Alan.

It does make a very big difference, well worth it.

--
David

On Sat, 24 Dec 2011 17:32:11 +0000, A.Lee wrote:

Honeywell for wireless stats.

I like Danfoss, but WTH...

They are the only makers that use the 800+MHz band (800mHz?),

Hum, where abouts in 800MHz? Presumably 863 to 870MHz aka Ch70. It
might get "interesting" when the switch over to digital television is
complete and the "800MHz band" is sold off for 4G mobile broadband
use. They will have access to Ch69. Of course Ch70 is currently used
by quite a bit of stuff already a lot of which uses a continious
carrier for radio microphones or cordless headphones. Unlike kit in
433Mhz that is mainly just a short burst when required, AFAIK there
are no continious carrier devices in 433.

You'll get your money back in reduced gas bills after a year or less by
fitting a room stat.

Aye, a system without a means to shut the boiler right down when the
house is warm will waste expensive gas. A programable stat also
enables sensible temperatures through out the day rather than just a
single one. Be aware that some programable stats are 5+2 days only,
fine for a M-F wage slave but not if your life style or work pattern
is not that boring. Go for one that can do true 7 day programing, you
can set it up for 5+2 if you want but you retain the flexibilty.

--
Cheers
Dave.

On Sat, 24 Dec 2011 19:32:09 +0000, geoff wrote:

I think Geoff was commenting on combis and slow water delivery.
You
need a very powerful one to be able to get a reasonable flow of
hot
water out of it.

Not really, mine is a 28kW which is fairly standard nowadays, and it
delivers sufficient flow rate.

28kW is quite a powerful boiler. A modernish house won't need
anything like that to keep it warm.

If I've got the maths right 28kW can only manage 10l/min raising the
temperature from 10 to 50C.

(28/(4.187*40))*60

--
Cheers
Dave.

"Dave Liquorice" wrote in message
ll.co.uk...

If I've got the maths right 28kW can only manage 10l/min raising the
temperature from 10 to 50C.

50C is a bit warm for baths and showers, maybe 44C.

On 24/12/2011 22:17, Dave Liquorice wrote:
On Sat, 24 Dec 2011 19:32:09 +0000, geoff wrote:

I think Geoff was commenting on combis and slow water delivery.
You
need a very powerful one to be able to get a reasonable flow of
hot
water out of it.
Not really, mine is a 28kW which is fairly standard nowadays, and it
delivers sufficient flow rate.
28kW is quite a powerful boiler. A modernish house won't need
anything like that to keep it warm.

If I've got the maths right 28kW can only manage 10l/min raising the
temperature from 10 to 50C.

(28/(4.187*40))*60

It would be 28kw for the hot water, heating would be rated at something
like 19kw maybe.

--
David

In message o.uk, Dave
Liquorice writes
On Sat, 24 Dec 2011 19:32:09 +0000, geoff wrote:

I think Geoff was commenting on combis and slow water delivery.
You
need a very powerful one to be able to get a reasonable flow of
hot
water out of it.

Not really, mine is a 28kW which is fairly standard nowadays, and it
delivers sufficient flow rate.

28kW is quite a powerful boiler. A modernish house won't need
anything like that to keep it warm.


But then, you're missing the bleeding obvious

you need to spec the boiler for hot water, not central heating


If I've got the maths right 28kW can only manage 10l/min raising the
temperature from 10 to 50C.

(28/(4.187*40))*60

I have no problem with the temp and flow rate

I think that Worcester boilers deliver more than the spec'd value in HW
mode 29k IIRC

--
geoff

On Sat, 24 Dec 2011 22:59:54 -0000, dennis@home wrote:

If I've got the maths right 28kW can only manage 10l/min raising
the
temperature from 10 to 50C.

50C is a bit warm for baths and showers, maybe 44C.

50C is a bit warm for baths but not for washing up, in fact 50C is
probably a bit cool for that...

50C is about what the mixer valve on the DHW output of our thermal
store is set to. Put the plug in, fill the bath with HW only and it's
about the right temperature when the about 4" deep, the pipe run is a
quite long to the bath though.

--
Cheers
Dave.

"John Rumm" wrote in message
o.uk...
On 24/12/2011 16:24, Alan wrote:
In message , John
Rumm wrote

Ideally you should have the rad valve setup that you have, plus a main
thermostat in the hall.

And if you want to save money put the thermostat in the room you use
most for sitting down. Don't have a thermostatic radiator valve on
radiators in the same room as the room thermostat.

If you get a wireless room thermostat you can experiment into the best
position within the house for fitting.

and you can always take the thermostatic head off the rad in that room -
with most that will have the effect of leaving the rad full on. (make sure
the rads have been properly balanced however, rather than relying on the
TRV to bodge it for you)

--
Cheers,

John.

Many thanks for you help
I don't understand what balancing the radiators mean How do I do this ?
Blair

On 25/12/2011 09:33, bm wrote:
"John wrote in message
o.uk...
On 24/12/2011 16:24, Alan wrote:
In messageUfCdnUsQDcY0bWjTnZ2dnUVZ8gKdnZ2d@brightvie w.co.uk, John
wrote

Ideally you should have the rad valve setup that you have, plus a main
thermostat in the hall.

And if you want to save money put the thermostat in the room you use
most for sitting down. Don't have a thermostatic radiator valve on
radiators in the same room as the room thermostat.

If you get a wireless room thermostat you can experiment into the best
position within the house for fitting.

and you can always take the thermostatic head off the rad in that room -
with most that will have the effect of leaving the rad full on. (make sure
the rads have been properly balanced however, rather than relying on the
TRV to bodge it for you)

--
Cheers,

John.

Many thanks for you help
I don't understand what balancing the radiators mean How do I do this ?


Basically ensuring that the water flow through each of the rads is
tweaked such that they all get equally hot, and heat up their respective
rooms at much the same rate.

Rads typically have a valve on both ends. One is called a lockshield
valve and is designed to be adjustable with a tool rather than by hand
(it normally has a cap over it so you don't see the tap part). When
balancing a system you adjust the setting of this valve on each of the
rads to ensure that water flows well through all of them.

If you don't do this, some rads will get very hot, some only warm, and
some may never heat at all. Some plumbers try to avoid doing this
properly by relying on the TRVs. Hence the hot rads warm their rooms to
the point that the TRV starts to shut off the water flow. This then
allows water to flow in the cooler rads and they can start heating their
rooms. However is not ideal since you get delayed heating in some rooms.


A couple of variations on the procedu

http://www.diyfaq.org.uk/plumbing/rad-balance.html

http://wiki.diyfaq.org.uk/index.php?...ng_radiator s


--
Cheers,

John.

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

On 25/12/2011 09:43, Terry Fields wrote:

John Rumm wrote:

With a
storage system like yours then you can specify a lower powered boiler
for running the rads, and heating the cylinder, since it does not need
to do the hot water on demand, but can take its time over it!

The house we bought some 18 months ago is fitted with a heat store,
and I love it to bits - although recognising there's no CH/DW backup
if things go wrong. However, the chap next door is a Gas Safe engineer
and familiar with the system as he has one as well.

Add an immersion heater or three to the store and you have a backup for
both CH and DHW ;-)




--
Cheers,

John.

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

On 24/12/2011 22:06, Dave Liquorice wrote:

Hum, where abouts in 800MHz? Presumably 863 to 870MHz aka Ch70. It
might get "interesting" when the switch over to digital television is
complete and the "800MHz band" is sold off for 4G mobile broadband
use. They will have access to Ch69.

Yes:
http://stakeholders.ofcom.org.uk/bin...xes/Update.pdf

I guess the threat to short-range devices (SRDs) will be mainly from the
4G/LTE base transmissions, rather than the closer (in frequency) but
lower power, mobiles. The frequency spacing between the top of the LTE
base transmit band and the lower edge of the SRD allocation is quite
wide - 42 MHz - so it ought to be possible to design new SRD kit with
sufficient immunity. Existing products might not have adequate
filtering and dynamic range though... That said, the LTE base
transmissions will be quite powerful - up to around 4 kW EIRP if all
three frequency blocks are in use - so it's by no means a trivial EMC
problem.

Of course Ch70 is currently used by quite a bit of stuff already a
lot of which uses a continious carrier for radio microphones or
cordless headphones. Unlike kit in 433Mhz that is mainly just a short
burst when required, AFAIK there are no continious carrier devices in
433.

UHF radio mics are moving from ch 69 to ch 38, are they not? And 433
MHz SRDs haven't been free from receiver immunity problems either (from
TETRA and 70 cm amateur radio).

--
Andy

In article , Andy Wade spambucket@maxw
ell.myzen.co.uk scribeth thus
On 24/12/2011 22:06, Dave Liquorice wrote:

Hum, where abouts in 800MHz? Presumably 863 to 870MHz aka Ch70. It
might get "interesting" when the switch over to digital television is
complete and the "800MHz band" is sold off for 4G mobile broadband
use. They will have access to Ch69.

Yes:
http://stakeholders.ofcom.org.uk/bin...xes/Update.pdf

I guess the threat to short-range devices (SRDs) will be mainly from the
4G/LTE base transmissions, rather than the closer (in frequency) but
lower power, mobiles. The frequency spacing between the top of the LTE
base transmit band and the lower edge of the SRD allocation is quite
wide - 42 MHz - so it ought to be possible to design new SRD kit with
sufficient immunity. Existing products might not have adequate
filtering and dynamic range though... That said, the LTE base
transmissions will be quite powerful - up to around 4 kW EIRP

So thats the base transmit power is it?..

if all
three frequency blocks are in use - so it's by no means a trivial EMC
problem.

Of course Ch70 is currently used by quite a bit of stuff already a
lot of which uses a continious carrier for radio microphones or
cordless headphones. Unlike kit in 433Mhz that is mainly just a short
burst when required, AFAIK there are no continious carrier devices in
433.

UHF radio mics are moving from ch 69 to ch 38, are they not? And 433
MHz SRDs haven't been free from receiver immunity problems either (from
TETRA and 70 cm amateur radio).


--
Tony Sayer

On 28/12/2011 12:14, tony sayer wrote:

So thats the base transmit power is it?..

Yes, it can definitely be in the kilowatt range. That's EIRP of course,
not TX output power.

http://stakeholders.ofcom.org.uk/bin...ary/condoc.pdf
gives the "base station in-block emission limit" as +61 dBm (~1.26 kW),
measured in 5 MHz bandwidth. In the full available 30 MHz that's around
7.5 kW, worst case. In practice max. EIRPs will apparently be 2-3 below
that, i.e. 4-point-something KW.

So on-beam, a field strength of ~35 V/m at 10 m range or 3.5 V/m at 100
metres...

Mobile power is only 200 mW per 5 MHz, so isn't such a worry.

--
Andy

"bm" wrote in message
...

In addition my experience with a combi boiler is that unless the hot runs
slow the water will not be warm enough. so it takes a long time to fill a
bath

High flow combis are available. Things have moved on.

"John Rumm" wrote in message
o.uk...

I think Geoff was commenting on combis and slow water delivery. You need a
very powerful one to be able to get a reasonable flow of hot water out of
it.

Powerful? A domestic gas meter can cope with approx 62kW. so a 35kW (approx
15 litres/min) is only using half the available capacity.

"bm" wrote in message
...

Boiler make? model? 3-way zone valve. Two zone valves. Room stat.

"geoff" wrote in message
...
In message , John Rumm
writes

As are pretty much all you buy these days... I think Geoff was commenting
on combis and slow water delivery. You need a very powerful one to be able
to get a reasonable flow of hot water out of it.

Not really, mine is a 28kW which is fairly standard nowadays, and it
delivers sufficient flow rate.

Combis suffer somewhat from a historical bad press

Maxie, you are so wise. Putting a Chav firmly in his place. You are a
fantastic man indeed.

In message o.uk, Dave
Liquorice writes
On Sat, 24 Dec 2011 19:32:09 +0000, geoff wrote:

I think Geoff was commenting on combis and slow water delivery.
You
need a very powerful one to be able to get a reasonable flow of
hot
water out of it.

Not really, mine is a 28kW which is fairly standard nowadays, and it
delivers sufficient flow rate.

28kW is quite a powerful boiler. A modernish house won't need
anything like that to keep it warm.


If I've got the maths right 28kW can only manage 10l/min raising the
temperature from 10 to 50C.

(28/(4.187*40))*60


From memory, (we had something like a 28kw combi in the old house, maybe
24KW) that sounds about right.

Sure it was sufficient for sinks and showers (good shower in fact, we
had plenty of mains pressure), but as Blair says takes a ges to fill a
bath
--
Chris French

"Dave Liquorice" wrote in message
ll.co.uk...
On Sat, 24 Dec 2011 19:32:09 +0000, geoff wrote:

I think Geoff was commenting on combis and slow water delivery.
You
need a very powerful one to be able to get a reasonable flow of
hot
water out of it.

Not really, mine is a 28kW which is fairly standard nowadays, and it
delivers sufficient flow rate.

28kW is quite a powerful boiler. A modernish house won't need
anything like that to keep it warm.

It is small for combi, which is rated on DHW performance.

If I've got the maths right 28kW can only manage 10l/min raising the
temperature from 10 to 50C.

28kW does about 11-12 litres/min, depending on model.

"chris French" wrote in message
...
In message o.uk, Dave
Liquorice writes
On Sat, 24 Dec 2011 19:32:09 +0000, geoff wrote:

I think Geoff was commenting on combis and slow water delivery.
You
need a very powerful one to be able to get a reasonable flow of
hot
water out of it.

Not really, mine is a 28kW which is fairly standard nowadays, and it
delivers sufficient flow rate.

28kW is quite a powerful boiler. A modernish house won't need
anything like that to keep it warm.


If I've got the maths right 28kW can only manage 10l/min raising the
temperature from 10 to 50C.

(28/(4.187*40))*60


From memory, (we had something like a 28kw combi in the old house, maybe
24KW) that sounds about right.

Sure it was sufficient for sinks and showers (good shower in fact, we had
plenty of mains pressure), but as Blair says takes a ges to fill a bath

35kW is becoming the norm. You can get a 50kW plus and the flow rate belts
out.

"John Rumm" wrote in message
o.uk...
On 25/12/2011 09:43, Terry Fields wrote:

John Rumm wrote:

With a
storage system like yours then you can specify a lower powered boiler
for running the rads, and heating the cylinder, since it does not need
to do the hot water on demand, but can take its time over it!

The house we bought some 18 months ago is fitted with a heat store,
and I love it to bits - although recognising there's no CH/DW backup
if things go wrong. However, the chap next door is a Gas Safe engineer
and familiar with the system as he has one as well.

Add an immersion heater or three to the store and you have a backup for
both CH and DHW ;-)

9kW immersions are available.

In article , Doctor Drivel wrote:

"chris French" wrote in message
...
In message o.uk,
Dave Liquorice writes
On Sat, 24 Dec 2011 19:32:09 +0000, geoff wrote:

I think Geoff was commenting on combis and slow water delivery.
You
need a very powerful one to be able to get a reasonable flow of
hot
water out of it.

Not really, mine is a 28kW which is fairly standard nowadays, and it
delivers sufficient flow rate.

28kW is quite a powerful boiler. A modernish house won't need anything
like that to keep it warm.


If I've got the maths right 28kW can only manage 10l/min raising the
temperature from 10 to 50C.

(28/(4.187*40))*60


From memory, (we had something like a 28kw combi in the old house,
maybe 24KW) that sounds about right.

Sure it was sufficient for sinks and showers (good shower in fact, we
had plenty of mains pressure), but as Blair says takes a ges to fill a
bath

35kW is becoming the norm. You can get a 50kW plus and the flow rate
belts out.

That is classed as "industrial" not domestic.

--
From KT24

Using a RISC OS computer running v5.16

"Terry Fields" wrote in message
...

John Rumm wrote:

With a
storage system like yours then you can specify a lower powered boiler
for running the rads, and heating the cylinder, since it does not need
to do the hot water on demand, but can take its time over it!

The house we bought some 18 months ago is fitted with a heat store,
and I love it to bits - although recognising there's no CH/DW backup
if things go wrong. However, the chap next door is a Gas Safe engineer
and familiar with the system as he has one as well.

The store runs at 72C max, and the boiler fires for a top-up when this
drops to 66C. Observation suggests this happens about every 9 hours
with no other demand for CH/DW, the heat-only 15 kW boiler burning for
~5 minutes for the top-up.

The rads heat up in less than a minute, but if the store temp drops
below 60 the CH is shut off until the store gets back to that
temperature.

SWMBO doesn't like my taking the front cover off the store and
observing the various temperature readouts, but I'm sure the boiler
can increase the store temp while someone's having a shower, for
example.

A nice simple unpressurised heat-only boiler; hot water on demand
24/7, and instant-heating rads - it has a lot going for it. OMMV...

Terry Fields

Sounds like a BoilerMate. They suffer from old-wives tales. Jobbing plumbers
do not understand them - they are good at toilet changing - and call them
sludge buckets. It is best to have the CH run off a coil in the store then
sludge occurs in the store.

Make sure the store is topped up every 3.5 years with 3 to 4 cans of
inhibitor - essential in a direct store.

As you noticed when the mid section gets below 60C the boiler cuts in
dumping "ALL" the boilers heat at the top of the store. So if a shower is
taken, a beefy boiler can be reheating faster than the draw-off. Their
selling point was that a smaller boiler can be fitted to save costs. But now
larger boilers are not expensive and many one size fits all are around as
they modulate.

As long as the flow and return pipes are the right size, you cannot fit a
large boiler onto a directly heated thermal store - it dumps all its heat
into the store. A very large boiler can reheat in few minutes and no adverse
effects. An over-large boiler on a direct rad system will result in boiler
cycling and cause premature failure of controls and maybe be the heat
exchanger.

On 29/12/2011 17:47, Doctor Drivel wrote:

"chris French" wrote in message
...
In message o.uk,
Dave Liquorice writes
On Sat, 24 Dec 2011 19:32:09 +0000, geoff wrote:

I think Geoff was commenting on combis and slow water delivery.
You
need a very powerful one to be able to get a reasonable flow of
hot
water out of it.

Not really, mine is a 28kW which is fairly standard nowadays, and it
delivers sufficient flow rate.

28kW is quite a powerful boiler. A modernish house won't need
anything like that to keep it warm.


If I've got the maths right 28kW can only manage 10l/min raising the
temperature from 10 to 50C.

(28/(4.187*40))*60


From memory, (we had something like a 28kw combi in the old house,
maybe 24KW) that sounds about right.

Sure it was sufficient for sinks and showers (good shower in fact, we
had plenty of mains pressure), but as Blair says takes a ges to fill a
bath

35kW is becoming the norm.

Having lived with a 35kW combi in the past, I would count that as about
a realistic minimum if you need bath filling. Great showers, but still
fairly feeble for volume delivery in the winter.

You can get a 50kW plus and the flow rate
belts out.

It will be better but not spectacular. You are also getting to the stage
where you are going to run out of flow capacity on a standard domestic
meter and governor if it has to share the supply with much else.


--
Cheers,

John.

/================================================== ===============\
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|-----------------------------------------------------------------|
| John Rumm - john(at)internode(dot)co(dot)uk |
\================================================= ================/

On 29/12/2011 11:19, Doctor Drivel wrote:

"John Rumm" wrote in message
o.uk...

I think Geoff was commenting on combis and slow water delivery. You
need a very powerful one to be able to get a reasonable flow of hot
water out of it.

Powerful? A domestic gas meter can cope with approx 62kW. so a 35kW
(approx 15 litres/min) is only using half the available capacity.

Not sure what your point is...

Lots of installers still slap in 24kW combis for moderate sized
households, and their DHW performance is fairly feeble, and hence it
does the reputation of the breed as a whole a disservice.

I would class 35kW and up as a moderately powerful combi, in the sense
that is about the point where it becomes tolerable to live with in a
house that uses the bath reasonably often. Many makers don't do anything
much above 40kW for the domestic market.

With the fairly decent cold main feed we have in this place, even a 60kW
combi would be marginal.

If you were selecting a PHE for a heatbank fed from a decent mains
supply, you would probably stick a 100kW unit in there to make sure you
always got adequate performance from it.


--
Cheers,

John.

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