I have a brand new combi running 18 radiators + 1 shower in my house. No
complaints there.

Problem is that the radiators seem to be getting very cold very quickly as
soon as the boiler is switched off. My suspicion is that the cause could be
because some of the pipes (copper) hat feed the downstairs radiators are not
insulated. I have a 1m high space under the house, where the pipes are
located, and it is freezing cold and drafty there.

Does it make sense? Will it be a good idea to insulate the pipes? It
shouldn't be a very big job.

What shall I use? I was thinking about something like this (
http://www.screwfix.com/app/sfd/cat/...0943&ts=33331), but: 1. it
seem to come in various levels of thinkness (which is suitable?), and 2. it
may be tricky to fit in some places.

Any advice will be much appreciated.

JoeJoe wrote:
I have a brand new combi running 18 radiators + 1 shower in my house. No
complaints there.

Problem is that the radiators seem to be getting very cold very quickly as
soon as the boiler is switched off. My suspicion is that the cause could be
because some of the pipes (copper) hat feed the downstairs radiators are not
insulated. I have a 1m high space under the house, where the pipes are
located, and it is freezing cold and drafty there.

Does it make sense?

Not really. Once the boiler shuts off, there is no more heat input into
the system. The various components will lose heat to the surroundings.
The rate of this heat loss will depend on how good each component is at
losing heat. Radiators are, by design, good at losing heat.


Will it be a good idea to insulate the pipes? It
shouldn't be a very big job.

Certainly not a bad idea to insulate them, but it won't make a
measurable difference to how quickly your radiators lose heat.


What shall I use? I was thinking about something like this (
http://www.screwfix.com/app/sfd/cat/...10943&ts=33331)

That's the stuff.


but: 1. it
seem to come in various levels of thinkness (which is suitable?)

The thickest you can fit in.


and 2. it may be tricky to fit in some places.

If you can't reach a particular piece of pipe, just leave it.


--
Grunff

"JoeJoe" wrote in message
...
I have a brand new combi running 18 radiators + 1 shower in my house. No
complaints there.

Problem is that the radiators seem to be getting very cold very quickly as
soon as the boiler is switched off.

Good. It means they are doing their job, i.e. radiating, very well.


My suspicion is that the cause could be
because some of the pipes (copper) hat feed the downstairs radiators are
not
insulated. I have a 1m high space under the house, where the pipes are
located, and it is freezing cold and drafty there.

Does it make sense?

No. 99% of the heat loss from the radiators will be to the room itself. Only
a tiny part will go back down the thin pipes to radiate under the floor.


Will it be a good idea to insulate the pipes?

Of course. You're losing heat to the underfloor space all the time the pipes
are hot while the boiler is on.
--
Dave Baker
Puma Race Engines
www.pumaracing.co.uk
Camp USA engineer minces about for high performance specialist (4,4,7)

In article ,
JoeJoe wrote:
I have a brand new combi running 18 radiators + 1 shower in my house. No
complaints there.

Problem is that the radiators seem to be getting very cold very quickly
as soon as the boiler is switched off. My suspicion is that the cause
could be because some of the pipes (copper) hat feed the downstairs
radiators are not insulated. I have a 1m high space under the house,
where the pipes are located, and it is freezing cold and drafty there.

If the boiler is off there's no point in the pump running so the
temperature of pipes elsewhere shouldn't make any difference.

--
*If love is blind, why is lingerie so popular?

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

On Tue, 12 Dec 2006 14:27:21 -0000, "JoeJoe" wrote:

|I have a brand new combi running 18 radiators + 1 shower in my house. No
|complaints there.
|
|Problem is that the radiators seem to be getting very cold very quickly as
|soon as the boiler is switched off. My suspicion is that the cause could be
|because some of the pipes (copper) hat feed the downstairs radiators are not
|insulated. I have a 1m high space under the house, where the pipes are
|located, and it is freezing cold and drafty there.
|
|Does it make sense? Will it be a good idea to insulate the pipes? It
|shouldn't be a very big job.
|
|What shall I use? I was thinking about something like this (
|http://www.screwfix.com/app/sfd/cat/...0943&ts=33331), but: 1. it
|seem to come in various levels of thinkness (which is suitable?), and 2. it
|may be tricky to fit in some places.
|
|Any advice will be much appreciated.

Definitely insulate under floor pipes *ASAP*. I am in process of doing
some myself. I am using the Water Regulations stuff from Wicks, IMO
well worth it because of the thickness of the insulation. It is very stiff
and difficult to get on the pipe. I open the insulation up till the other
side almost splits, shove it on the pipe, and hold it on place with Cable
Ties. Where necessary I trim a bit of insulation away, with my specially
sharpened Swiss Army Knife.

The only problem I have had is that my Swiss Army Knife is used as a fob
for the Car keys, and I left it under the floor, and did not want to go
there to retrieve it in half way clean clothes. :-(

--
Dave Fawthrop dave hyphenologist co uk Google Groups is IME the *worst*
method of accessing usenet. GG subscribers would be well advised get a
newsreader, say Agent, and a newsserver, say news.individual.net. These
will allow them: to see only *new* posts, a killfile, and other goodies.

On Tue, 12 Dec 2006 14:43:43 +0000, Grunff wrote:

|JoeJoe wrote:
| I have a brand new combi running 18 radiators + 1 shower in my house. No
| complaints there.
|
| Problem is that the radiators seem to be getting very cold very quickly as
| soon as the boiler is switched off. My suspicion is that the cause could be
| because some of the pipes (copper) hat feed the downstairs radiators are not
| insulated. I have a 1m high space under the house, where the pipes are
| located, and it is freezing cold and drafty there.
|
| Does it make sense?
|
|Not really. Once the boiler shuts off, there is no more heat input into
|the system. The various components will lose heat to the surroundings.
|The rate of this heat loss will depend on how good each component is at
|losing heat. Radiators are, by design, good at losing heat.
|
|
| Will it be a good idea to insulate the pipes? It
| shouldn't be a very big job.
|
|Certainly not a bad idea to insulate them, but it won't make a
|measurable difference to how quickly your radiators lose heat.

But will make a huge difference to your Gas bill.
--
Dave Fawthrop dave hyphenologist co uk Google Groups is IME the *worst*
method of accessing usenet. GG subscribers would be well advised get a
newsreader, say Agent, and a newsserver, say news.individual.net. These
will allow them: to see only *new* posts, a killfile, and other goodies.

Dave Fawthrop wrote:

|Certainly not a bad idea to insulate them, but it won't make a
|measurable difference to how quickly your radiators lose heat.

But will make a huge difference to your Gas bill.

With 18 radiators I think the ££ difference would be pretty insignificant.

--
http://gymratz.co.uk - Best Gym Equipment & Bodybuilding Supplements UK.
http://gymratz.co.uk/polar-heart-rate-monitors/ Polar HeartRate Monitors
http://fitness-equipment-uk.com - UK's No.1 Fitness Equipment Suppliers.
http://water-rower.co.uk - Worlds best prices on the Worlds best Rower.

The message
from "JoeJoe" contains these words:

Problem is that the radiators seem to be getting very cold very quickly as
soon as the boiler is switched off. My suspicion is that the cause could be
because some of the pipes (copper) hat feed the downstairs radiators
are not
insulated.

As others have said, it'll only really matter if the pump is still
running once the boiler's off. I'd lag the pipes in the cold space
anyway, but radiators do cool down quickly - that's what they're for!

--
Skipweasel
Pay no attention to that man behind the curtain.

Dave Fawthrop wrote:

But will make a huge difference to your Gas bill.

I doubt it, a few percent at best. No doubt it's worth doing, but don't
expect huge savings.


--
Grunff

We were somewhere around Barstow, on the edge of the desert, when the
drugs began to take hold. I remember "JoeJoe" saying
something like:

Problem is that the radiators seem to be getting very cold very quickly as
soon as the boiler is switched off. My suspicion is that the cause could be
because some of the pipes (copper) hat feed the downstairs radiators are not
insulated. I have a 1m high space under the house, where the pipes are
located, and it is freezing cold and drafty there.

Does it make sense? Will it be a good idea to insulate the pipes? It
shouldn't be a very big job.

The underhouse pipes are obviously losing heat - and if the pump is
continuing to run after the boiler shuts down, then the colder water
from the pipes is entering the radiators and cooling them down. Even if
the pump isn't running, the next time it starts, it's shoving cold water
into the rads before the hot stuff (which has lost some heat to the
underfloor) arrives.

So yes; insulate, insulate, insulate.
--

Dave

On Tue, 12 Dec 2006 18:18:15 +0000, Grunff wrote:

|Dave Fawthrop wrote:
|
| But will make a huge difference to your Gas bill.
|
|I doubt it, a few percent at best. No doubt it's worth doing, but don't
|expect huge savings.

Well in my case the pipes have about half the surface area of the
radiators, at double the differential temperature.

Work it out for yourself, I am busy with the job.
--
Dave Fawthrop dave hyphenologist co uk Google Groups is IME the *worst*
method of accessing usenet. GG subscribers would be well advised get a
newsreader, say Agent, and a newsserver, say news.individual.net. These
will allow them: to see only *new* posts, a killfile, and other goodies.

"Grimly Curmudgeon" wrote in message
...
We were somewhere around Barstow, on the edge of the desert, when the
drugs began to take hold. I remember "JoeJoe" saying
something like:

Problem is that the radiators seem to be getting very cold very quickly as
soon as the boiler is switched off. My suspicion is that the cause could
be
because some of the pipes (copper) hat feed the downstairs radiators are
not
insulated. I have a 1m high space under the house, where the pipes are
located, and it is freezing cold and drafty there.

Does it make sense? Will it be a good idea to insulate the pipes? It
shouldn't be a very big job.

The underhouse pipes are obviously losing heat - and if the pump is
continuing to run after the boiler shuts down, then the colder water
from the pipes is entering the radiators and cooling them down. Even if
the pump isn't running, the next time it starts, it's shoving cold water
into the rads before the hot stuff (which has lost some heat to the
underfloor) arrives.

So yes; insulate, insulate, insulate.

Thank you all for the very useful advice. Although I am sure that the pump
does not continue to run once the boiler is turned off, it still makes sense
to insulate the pipes anyway.

Looks like my Saturday is booked then... ;-(

On Tue, 12 Dec 2006 17:13:41 +0000 (GMT), Dave Plowman (News) wrote:

If the boiler is off there's no point in the pump running ...

Unless the boiler needs pump overrun which modern low capacity ali ones
generally do. B-)

so the temperature of pipes elsewhere shouldn't make any difference.

Well I suspect that exceeive cooling of the pipes could well set up
gravity flow through the rads, though that would depend a bit on the
layout. Certainly worth insulating the pipes in the void but prehaps
leave a short section un insulated to provide a little background warmth
down there.

--
Cheers
Dave. pam is missing e-mail

In message , "Dave Plowman (News)"
writes
If the boiler is off there's no point in the pump running so the
temperature of pipes elsewhere shouldn't make any difference.

Does nobody over run the pump anymore?
--
Clint Sharp

In article ,
Clint Sharp wrote:
If the boiler is off there's no point in the pump running so the
temperature of pipes elsewhere shouldn't make any difference.

Does nobody over run the pump anymore?

Until the rads go cold?

--
*Whatever kind of look you were going for, you missed.

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

JoeJoe wrote:
I have a brand new combi running 18 radiators + 1 shower in my house. No
complaints there.

Problem is that the radiators seem to be getting very cold very quickly as
soon as the boiler is switched off. My suspicion is that the cause could be
because some of the pipes (copper) hat feed the downstairs radiators are not
insulated. I have a 1m high space under the house, where the pipes are
located, and it is freezing cold and drafty there.

Just a thought - check that all your radiators are properly bled of air
- a part full rad looses heat faster when the boiler is switched off

Charlie

In message , "Dave Plowman (News)"
writes
In article ,
Clint Sharp wrote:
If the boiler is off there's no point in the pump running so the
temperature of pipes elsewhere shouldn't make any difference.

Does nobody over run the pump anymore?

Until the rads go cold?

That wasn't quite the point I was making, just that "If the boiler is
off there's no point in the pump running" is not entirely accurate, pump
overrun can help the system extract heat from the boiler that would
otherwise be wasted. Something in the back of my mind tells me it's
kinder to boilers as well but that may not be true.
--
Clint Sharp