I'll try to keep this as short as possible. My heating system is 28
years old and is 8mm microbore with standard steel panel radiators and
an indirect hot water cylinder.

I spent a couple of weeks this summer totally overhauling the system by
removing all the radiators and flushing them, flushing each individual
pipe in the system with (cough) mains pressure water in both directions
at the pump attachments and fitting 15mm radiator valves with reducers
to 8mm.

Quite a lot of gunk came out of the rads and the pipe work and now that
the system is refilled and bled the rads get hot much quicker than
before.

It's the balancing that I'm having problems with. I've read all the info
I can find and frankly none of it seems to have the desired effect on my
system and there are other problems.

My pump has 3 speed settings and the middle setting seems to work best.

I started by turning all the main valves and TRVs fully open and the
lock shield valves to a quarter turn from off and immediately noticed
quite noticeable sounds of rushing water in a few of the radiators. If I
open the lock shields the noise goes away but I now have no control over
the flow through the radiators.

I am trying to use one of these http://tinyurl.com/8uuqqvu to measure
the temperatures but I can't get a reading from the pipes as they are
only 8mm and trying it on the bottom corners of the rads gives wildly
varying results. I have heard mention of putting a patch of black tape
on the rads but, is this really necessary?

I can't get near to the required drop across the rads and soon get back
to the point where the rushing sound returns before any difference is
noticeable.

What am I doing wrong and what should I be doing?
--
P

On Wed, 10 Oct 2012 09:53:25 +0100, Percy wrote:

What am I doing wrong and what should I be doing?

Is the 8mm pipe work connected to a manifold(s) somewhere? I suspect it
is rather than being a loop with the rads connected in parallel across
it. I'm not sure how one would go about balancing a manifold based
system, does the FAQ cover it?

Noise indicative that the water is being pushed too fast through a small
gap, turn the pump down. Also with the water circulating fast it doesn't
get a chance to lose heat to the room, hence not able to get the 10
degree or so drop across a given rad.

--
Cheers
Dave.

In article , Percy writes
I'll try to keep this as short as possible. My heating system is 28
years old and is 8mm microbore with standard steel panel radiators and
an indirect hot water cylinder.

It's the balancing that I'm having problems with. I've read all the info
I can find and frankly none of it seems to have the desired effect on my
system and there are other problems.

Is this the method you are following:

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

My pump has 3 speed settings and the middle setting seems to work best.

That's a good start, yes.

I started by turning all the main valves and TRVs fully open and the
lock shield valves to a quarter turn from off and immediately noticed
quite noticeable sounds of rushing water in a few of the radiators. If I
open the lock shields the noise goes away but I now have no control over
the flow through the radiators.

Classic noob mistake, what you have done is throttle the system and that
is not what you do at all. You start with all lockshields fully open and
only start to close ones that show low temperature drop. At the end of
the process (after many cycles) you will expect to see lockshields on
large rads on long pipe runs far from the boiler still fully open and
small rads close to the boiler perhaps on the quarter or half turn open
that you have attempted. Use a measurement table as described and
measure all rads within 5 or 10 mins, then work out how much each is to
be adjusted on that loop and make all the changes at once before waiting
20mins for the system to stabilise again. You can make gross changes at
the start eg. if a rad is dropping virtually nothing then go from fully
open (say 8/9 turns) to half shut (4T) in one loop, if it's still
dropping next to nothing then half the opening again on the next loop
(2T) and fine tune once you start getting meaningful drops. As Phil
suggests in his guide I note lockshield open-ness as number of quarter
turns from closed as this avoids the use of fractions.

I am trying to use one of these http://tinyurl.com/8uuqqvu to measure
the temperatures but I can't get a reading from the pipes as they are
only 8mm and trying it on the bottom corners of the rads gives wildly
varying results. I have heard mention of putting a patch of black tape
on the rads but, is this really necessary?

The reason for the tape has been well described here before and yes it
is necessary. Your tape is in the wrong place though, hottest place is
at the top of the panel closest to the inlet end, coldest place is at
the bottom of the panel closest to the outlet end, this is where the
patches should be. If you need help determining which is flow and return
then read the guide at the link again. A patch of tape about 30mm square
is fine (it doesn't need to be black, I use white) and to keep the
measurement target small you can just use the IR thermometer in contact
with the target (most have a window aperture about 20mm dia).

I can't get near to the required drop across the rads and soon get back
to the point where the rushing sound returns before any difference is
noticeable.

There is no such thing as a 'required' drop (read the process and
philosophy described on the above link again), the system drop is a
function of boiler output and total rad loading and unless you have
designed it so the rads can sink all the heat that the boiler can
produce then the overall return temperature will be higher than the
ideal and you wont get the magic 20, 15 or 10 degree drop that you hope
for. Throttling the system to compensate for this and force a lower
return temperature is not the way to do it, you'll just have to put up
with the lower drop.

What am I doing wrong and what should I be doing?

Have another go and post back if you still have probs.
--
fred
it's a ba-na-na . . . .

On 10/10/2012 09:53, Percy wrote:

I am trying to use one of these http://tinyurl.com/8uuqqvu to measure
the temperatures but I can't get a reading from the pipes as they are
only 8mm and trying it on the bottom corners of the rads gives wildly
varying results. I have heard mention of putting a patch of black tape
on the rads but, is this really necessary?

You should be able to get a reading off the painted rad close to the
valve position. You won't get a sensible[1] reading of the unpainted
pipe or valve metalwork though, without putting a patch of tape on them
first and placing the thermometer close to the patch.

[1] The emissivity of the surface will be notably different from that
assumed by the thermometer. Some (possibly yours) have the ability to
adjust the assumed figure, but its quite a faff getting the number
"right" for any given material. Its generally easier to go with the
default value that works for most non metalic surfaces and use a bit of
tape as a target.


--
Cheers,

John.

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

In article , fred writes

There is no such thing as a 'required' drop (read the process and
philosophy described on the above link again), the system drop is a
function of boiler output and total rad loading and unless you have
designed it so the rads can sink all the heat that the boiler can
produce then the overall return temperature will be higher than the
ideal and you wont get the magic 20, 15 or 10 degree drop that you hope
for. Throttling the system to compensate for this and force a lower
return temperature is not the way to do it, you'll just have to put up
with the lower drop.

What I should have said was that the target is the same drop across all
rads rather than some target numerical drop. V small rads will rarely
achieve full drop though and you just have to live with that/those
one(s) being different.
--
fred
it's a ba-na-na . . . .

Nothing to do with the problem but the title of this thread had me wondering
if it was.
Overbalancing radiators, IE they were in a pile and over balanced
or
You were a novelty act and wre trying to balance radiators, where I
wondered?
or
what in fact you did mean that they were all doing their own thing and
casing problems.

Briabn

--
From the Sofa of Brian Gaff Reply address is active
"Percy" wrote in message ...
I'll try to keep this as short as possible. My heating system is 28 years
old and is 8mm microbore with standard steel panel radiators and an
indirect hot water cylinder.

I spent a couple of weeks this summer totally overhauling the system by
removing all the radiators and flushing them, flushing each individual
pipe in the system with (cough) mains pressure water in both directions at
the pump attachments and fitting 15mm radiator valves with reducers to
8mm.

Quite a lot of gunk came out of the rads and the pipe work and now that
the system is refilled and bled the rads get hot much quicker than before.

It's the balancing that I'm having problems with. I've read all the info I
can find and frankly none of it seems to have the desired effect on my
system and there are other problems.

My pump has 3 speed settings and the middle setting seems to work best.

I started by turning all the main valves and TRVs fully open and the lock
shield valves to a quarter turn from off and immediately noticed quite
noticeable sounds of rushing water in a few of the radiators. If I open
the lock shields the noise goes away but I now have no control over the
flow through the radiators.

I am trying to use one of these http://tinyurl.com/8uuqqvu to measure the
temperatures but I can't get a reading from the pipes as they are only 8mm
and trying it on the bottom corners of the rads gives wildly varying
results. I have heard mention of putting a patch of black tape on the rads
but, is this really necessary?

I can't get near to the required drop across the rads and soon get back to
the point where the rushing sound returns before any difference is
noticeable.

What am I doing wrong and what should I be doing?
--
P

On Wed, 10 Oct 2012, "Brian Gaff" writ:

Nothing to do with the problem but the title of this thread had me wondering
if it was.
Overbalancing radiators, IE they were in a pile and over balanced
or
You were a novelty act and wre trying to balance radiators, where I
wondered?
or
what in fact you did mean that they were all doing their own thing and
casing problems.

Briabn


Brian, I really think you should get out more )
--
P

On Wednesday, October 10, 2012 9:53:27 AM UTC+1, Percy wrote:
I'll try to keep this as short as possible. My heating system is 28

years old and is 8mm microbore with standard steel panel radiators and

an indirect hot water cylinder.



I spent a couple of weeks this summer totally overhauling the system by

removing all the radiators and flushing them, flushing each individual

pipe in the system with (cough) mains pressure water in both directions

at the pump attachments and fitting 15mm radiator valves with reducers

to 8mm.



Quite a lot of gunk came out of the rads and the pipe work and now that

the system is refilled and bled the rads get hot much quicker than

before.



It's the balancing that I'm having problems with. I've read all the info

I can find and frankly none of it seems to have the desired effect on my

system and there are other problems.



My pump has 3 speed settings and the middle setting seems to work best.



I started by turning all the main valves and TRVs fully open and the

lock shield valves to a quarter turn from off and immediately noticed

quite noticeable sounds of rushing water in a few of the radiators. If I

open the lock shields the noise goes away but I now have no control over

the flow through the radiators.



I am trying to use one of these http://tinyurl.com/8uuqqvu to measure

the temperatures but I can't get a reading from the pipes as they are

only 8mm and trying it on the bottom corners of the rads gives wildly

varying results. I have heard mention of putting a patch of black tape

on the rads but, is this really necessary?



I can't get near to the required drop across the rads and soon get back

to the point where the rushing sound returns before any difference is

noticeable.



What am I doing wrong and what should I be doing?


People have explained. Just one point: balancing rad temp drops isn't quite what's wanted, the goal is to balance room temps as near as possible before employing the TRVs. The 2 thing aren't quite the same because
a) rad area to room area varies
b) wall area to room area varies, affecting heat loss per floor area
c) other factors also effect the wanted heat output per room, such as desired temp, exterior wall finishes, sunlight etc


NT

On Thu, 11 Oct 2012 04:17:52 -0700 (PDT), wrote:

On Wednesday, October 10, 2012 9:53:27 AM UTC+1, Percy wrote:
snippity snip

What am I doing wrong and what should I be doing?


People have explained. Just one point: balancing rad temp drops isn't quite what's wanted, the
goal is to balance room temps as near as possible before employing the TRVs. The 2 thing aren't
quite the same because
a) rad area to room area varies
b) wall area to room area varies, affecting heat loss per floor area
c) other factors also effect the wanted heat output per room, such as desired temp, exterior
wall finishes, sunlight etc

And the procedure to achieve this is what?

Sorry, but I think balancing radiator temperature drops IS what's wanted. That way each
radiator will achieve its design output or as near as the plumbing will permit. The TRV's
take up the inevitable mismatch between (a) what the designer had in mind, and (b) what
temperature the end requires from day to day.

Of course should you happen to have a grossly oversized radiator it is sensible to
throttle its LSV back thus increasing its temp drop and (counter-intuitively) reducing its
heat output. This will free up some extra heat to go to other radiators, at least one of
which is invariably under-sized.

The rule to remember is that throttling back an LSV reduces the water speed through the
radiator, and consequently the water cools more and the outlet temperature becomes lower.
In other words the temperature drop increases and the average radiator temperature is
lower so less heat is given out to the room.

Perhaps this is what you're getting at? Is it not clear in the FAQ, it's ages since I've
read it?

--
Phil Addison

On 15/10/2012 09:56, Percy wrote:


As requested, a follow up on progress so far. Starting from scratch as
per FAQ, all the upstairs and one downstairs radiator were at least 10C
more than the other downstairs radiators. Fearing a long drawn out,
running around like a blue a***d fly event, I opted to take a simple
measurement of the temperature at the top centre of each radiator as
they warmed up, repeated over a number of cycles from cold. I was soon
able to bring them all within a few degrees of each other and now find
that the radiators that were hottest are within a turn or less of off.
The colder radiators are still turned fully on.

None of the drops across the radiators are anywhere near the much quoted
11C but they are all warming up evenly and seem to be within a degree or
two of each other when hot.

Are the drops more or less than 11 degrees? If less, can you run the
pump on a lower setting? This should increase the drop.

I shall now play about with refining the
settings but I am a much happier newbie than I was.

Perhaps the quick and simple method I employed to get to a starting
point may be worth mentioning in the FAQ.

An even quicker and dirtier method is to go round feeling the rads with
a calibrated hand, and to throttle back the hottest ones. Getting
exactly the same drop isn't that important - what really matters is
making sure that one or two rads are not hogging all the flow to the
detriment of the others. As long as they *all* get hot at about the same
rate, that's good enough.
--
Cheers,
Roger
____________
Please reply to Newsgroup. Whilst email address is valid, it is seldom
checked.

On Mon, 15 Oct 2012 09:56:18 +0100, Percy wrote:

On Wed, 10 Oct 2012, "fred" writ:

In article , Percy writes

As requested, a follow up on progress so far. Starting from scratch as
per FAQ, all the upstairs and one downstairs radiator were at least 10C
more than the other downstairs radiators. Fearing a long drawn out,
running around like a blue a***d fly event, I opted to take a simple
measurement of the temperature at the top centre of each radiator as
they warmed up, repeated over a number of cycles from cold. I was soon
able to bring them all within a few degrees of each other and now find
that the radiators that were hottest are within a turn or less of off.
The colder radiators are still turned fully on.

It is quite normal to finish with some LSVs nearly off, and the previously coldest rad
wide open.

None of the drops across the radiators are anywhere near the much quoted
11C but they are all warming up evenly and seem to be within a degree or

It may well be much quoted, but not by the FAQ. That states "Similarly the oft quoted 11
deg C drop across the radiators is really nothing to do with the radiators! It is the
temperature gradient the *boiler* is designed to produce when it is going flat out *and*
the pump is producing the specified flow rate. So if you have less than 11C drop it just
means that either you have too high a water circulation rate or/and the radiators are not
large enough to extract the full rating from the boiler."

As Roger says, if you are getting a lot less than 11 degrees on ALL of them you could
benefit by slowing the pump.

two of each other when hot. I shall now play about with refining the
settings but I am a much happier newbie than I was.

That's what we aim for!

Perhaps the quick and simple method I employed to get to a starting
point may be worth mentioning in the FAQ.

Yes the FAQ does need expanding there. Roger has the right idea, starting from cold as
soon as the boiler starts to fire, go round and find the ones starting to get hot and
throttle them back till the cold ones start receiving hot water. Of course if you already
know you have some cold ones, make sure their LSVs are wide open before you start. In a
properly balanced system the will all start heating up when the boler fires. Sometimes
this is impossible which means there is a design fault in the sytem, usually a too long
run of too small a bore pipework.

The FAQ is really written for a new or unknown system.

Thanks again!


--
Phil Addison

On 17/10/2012 00:24, Phil Addison wrote:
On Mon, 15 Oct 2012 09:56:18 +0100, Percy wrote:

Perhaps the quick and simple method I employed to get to a starting
point may be worth mentioning in the FAQ.

Yes the FAQ does need expanding there. Roger has the right idea, starting from cold as

If you want, dump the text from the FAQ into a wiki article and tweak it
about, and I will knobble the original FAQ page and point it at the wiki
version when you are happy. Or failing that, add some supporting notes
on the wiki and I can link them from the end of the FAQ


--
Cheers,

John.

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

On Wed, 17 Oct 2012 02:23:22 +0100, John Rumm wrote:

On 17/10/2012 00:24, Phil Addison wrote:
On Mon, 15 Oct 2012 09:56:18 +0100, Percy wrote:

Perhaps the quick and simple method I employed to get to a starting
point may be worth mentioning in the FAQ.

Yes the FAQ does need expanding there. Roger has the right idea, starting from cold as

If you want, dump the text from the FAQ into a wiki article and tweak it
about, and I will knobble the original FAQ page and point it at the wiki
version when you are happy. Or failing that, add some supporting notes
on the wiki and I can link them from the end of the FAQ

I'm pushed for time but by all means copy the balancing faq across to the wiki if you care
to. Perhaps insert something along lines of "The procedure below is for a new or unknown
system, but if your system is 'sort-of' working you might save some time by starting with
the existing settings. Then starting from cold, as soon as the boiler starts to fire, go
round and find the rads starting to get hot and throttle them back till the cold ones
start receiving hot water as well. Of course if you already know you have some cold ones,
make sure their LSVs are wide open before you start. In a properly balanced system all
rads should start heating up together when the boiler fires.

Sometimes it isn't possible to achieve a balance which means there is a design fault in
the sytem, usually one (or more) rad fed with too long a run and/or insufficient pipe
bore."

--
Phil Addison

On 19/10/2012 00:23, Phil Addison wrote:
On Wed, 17 Oct 2012 02:23:22 +0100, John Rumm wrote:

On 17/10/2012 00:24, Phil Addison wrote:
On Mon, 15 Oct 2012 09:56:18 +0100, Percy wrote:

Perhaps the quick and simple method I employed to get to a starting
point may be worth mentioning in the FAQ.

Yes the FAQ does need expanding there. Roger has the right idea, starting from cold as

If you want, dump the text from the FAQ into a wiki article and tweak it
about, and I will knobble the original FAQ page and point it at the wiki
version when you are happy. Or failing that, add some supporting notes
on the wiki and I can link them from the end of the FAQ

I'm pushed for time but by all means copy the balancing faq across to the wiki if you care

My memory must be going... I went to copy the content, and then found
out that I had already done it in August!

to. Perhaps insert something along lines of "The procedure below is for a new or unknown
system, but if your system is 'sort-of' working you might save some time by starting with
the existing settings. Then starting from cold, as soon as the boiler starts to fire, go
round and find the rads starting to get hot and throttle them back till the cold ones
start receiving hot water as well. Of course if you already know you have some cold ones,
make sure their LSVs are wide open before you start. In a properly balanced system all
rads should start heating up together when the boiler fires.

Sometimes it isn't possible to achieve a balance which means there is a design fault in
the sytem, usually one (or more) rad fed with too long a run and/or insufficient pipe
bore."

Added...


--
Cheers,

John.

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

On Fri, 19 Oct 2012 15:19:54 +0100, John Rumm wrote:

My memory must be going... I went to copy the content, and then found
out that I had already done it in August!

Copy of what?

--
Phil Addison

On 20/10/2012 20:09, Phil Addison wrote:
On Fri, 19 Oct 2012 15:19:54 +0100, John Rumm wrote:

My memory must be going... I went to copy the content, and then found
out that I had already done it in August!

Copy of what?

I can't remember...

who am I anyway?

--
Cheers,

John.

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