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  #1   Report Post  
Simon Langford
 
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Default balancing radiators - is my boiler too small?

I'm having difficulting getting the radiators on the 2nd floor of our
house to heat up. My efforts have so far involved closing down the
LSVs almost completely on the hottest rads (kitchen area and ground
floor), leaving the LSVs wide open on the 2nd floor, and somewhere in
between on the 1st floor.

On balancing radiators, the FAQ says...

"The important thing is that the return water coming out of each
radiator is good and hot. If it's only warm you need to open its Lock
Shield Valve (LSV) some more, or if it's already wide open you have to
close the LSVs on the hottest radiators instead."

The problem is that the 2nd floor rads are still not hot (just warm),
and the ground and 1st floor rads now have cool return pipes. If I
open up the LSVs so get hot return pipes on the ground floor, then the
2nd floor rads are even less hot.

Do you think I need a bigger boiler (it's already a pretty big one)?
Or would a faster pump help?

Thanks,

Simon.
  #2   Report Post  
IMM
 
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"Simon Langford" wrote in message
om...
I'm having difficulting getting the radiators on the 2nd floor of our
house to heat up. My efforts have so far involved closing down the
LSVs almost completely on the hottest rads (kitchen area and ground
floor), leaving the LSVs wide open on the 2nd floor, and somewhere in
between on the 1st floor.

On balancing radiators, the FAQ says...

"The important thing is that the return water coming out of each
radiator is good and hot. If it's only warm you need to open its Lock
Shield Valve (LSV) some more, or if it's already wide open you have to
close the LSVs on the hottest radiators instead."

The problem is that the 2nd floor rads are still not hot (just warm),
and the ground and 1st floor rads now have cool return pipes. If I
open up the LSVs so get hot return pipes on the ground floor, then the
2nd floor rads are even less hot.

Do you think I need a bigger boiler (it's already a pretty big one)?
Or would a faster pump help?


Are the pipes large enough? Is there too many elbows rather than bends?
The pump may be too small or not on the highest setting.

How large is boiler? Size of house, etc?


  #3   Report Post  
Dave Plowman (News)
 
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In article ,
Simon Langford wrote:
The problem is that the 2nd floor rads are still not hot (just warm),
and the ground and 1st floor rads now have cool return pipes. If I
open up the LSVs so get hot return pipes on the ground floor, then the
2nd floor rads are even less hot.


Do you think I need a bigger boiler (it's already a pretty big one)?
Or would a faster pump help?


The size of the boiler makes no difference to the water circulation. If
you aren't getting even temperatures across all the rads, then this is the
problem.

--
*Don't squat with your spurs on *

Dave Plowman London SW
To e-mail, change noise into sound.
  #4   Report Post  
Phil Addison
 
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On 6 Oct 2004 04:14:24 -0700, (Simon Langford)
wrote:

I'm having difficulting getting the radiators on the 2nd floor of our
house to heat up. My efforts have so far involved closing down the
LSVs almost completely on the hottest rads (kitchen area and ground
floor), leaving the LSVs wide open on the 2nd floor, and somewhere in
between on the 1st floor.


Have you actually followed the detailed procedure, or is the above all
you have done?

On balancing radiators, the FAQ says...

"The important thing is that the return water coming out of each
radiator is good and hot. If it's only warm you need to open its Lock
Shield Valve (LSV) some more, or if it's already wide open you have to
close the LSVs on the hottest radiators instead."


True, but it then gives detailed instructions on what to do.

The problem is that the 2nd floor rads are still not hot (just warm),
and the ground and 1st floor rads now have cool return pipes. If I
open up the LSVs so get hot return pipes on the ground floor, then the
2nd floor rads are even less hot.

Do you think I need a bigger boiler (it's already a pretty big one)?
Or would a faster pump help?


If you *have* followed the FAQ procedure, it seems that there is some
inadequacy in the plumbing design. To track this down, try the
following:

Turn off the boiler.
Open both valves fully on one radiator and close down all the others.
Turn boiler back on.

If that radiator heats up, repeat for each of the others in turn.

If you find one or more that won't heat, then either

the pipe run is too long for the bore used,

or the pump is not producing enough pressure (too small, broken, set too
slow),

or there is a blockage in the rad or pipework (sludge or airlock).

or a combination of these.

The boiler size would only be a problem if it is firing continuously
flat out and the radiators are still not getting all equally hot.

If that does not help you will need to give us much more details of the
system and what it is doing.

Phil
The uk.d-i-y FAQ is at
http://www.diyfaq.org.uk/
Remove NOSPAM from address to email me
  #5   Report Post  
Phil Addison
 
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On Wed, 6 Oct 2004 12:24:05 +0100, "IMM" wrote:


"Simon Langford" wrote in message
om...
I'm having difficulting getting the radiators on the 2nd floor of our
house to heat up. My efforts have so far involved closing down the
LSVs almost completely on the hottest rads (kitchen area and ground
floor), leaving the LSVs wide open on the 2nd floor, and somewhere in
between on the 1st floor.

On balancing radiators, the FAQ says...

"The important thing is that the return water coming out of each
radiator is good and hot. If it's only warm you need to open its Lock
Shield Valve (LSV) some more, or if it's already wide open you have to
close the LSVs on the hottest radiators instead."

The problem is that the 2nd floor rads are still not hot (just warm),
and the ground and 1st floor rads now have cool return pipes. If I
open up the LSVs so get hot return pipes on the ground floor, then the
2nd floor rads are even less hot.

Do you think I need a bigger boiler (it's already a pretty big one)?
Or would a faster pump help?


Are the pipes large enough? Is there too many elbows rather than bends?


How do you expect the original poster to know the answer to that?

Phil
The uk.d-i-y FAQ is at http://www.diyfaq.org.uk/
Remove NOSPAM from address to email me


  #6   Report Post  
Set Square
 
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In an earlier contribution to this discussion,
Simon Langford wrote:

I'm having difficulting getting the radiators on the 2nd floor of our
house to heat up. My efforts have so far involved closing down the
LSVs almost completely on the hottest rads (kitchen area and ground
floor), leaving the LSVs wide open on the 2nd floor, and somewhere in
between on the 1st floor.

On balancing radiators, the FAQ says...

"The important thing is that the return water coming out of each
radiator is good and hot. If it's only warm you need to open its Lock
Shield Valve (LSV) some more, or if it's already wide open you have to
close the LSVs on the hottest radiators instead."

The problem is that the 2nd floor rads are still not hot (just warm),
and the ground and 1st floor rads now have cool return pipes. If I
open up the LSVs so get hot return pipes on the ground floor, then the
2nd floor rads are even less hot.

Do you think I need a bigger boiler (it's already a pretty big one)?
Or would a faster pump help?

Thanks,

Simon.


Is the boiler running continuously, or is it cycling on and off on its own
stat? If the latter, the boiler has spare capacity - you're just not
harnessing it fully.

The water needs pumping round with a bit more urge - so that you can get
water to the 2nd floor radiators without starving the others. Does your pump
have a higher speed setting than you are currently using? If so, turn it up.
If not, fit a more powerful one.

You need to be able to get an adequate flow to all radiators - with a
uniform temperature drop - with all the TRVs wide open. Only then should you
turn down the TRVs to establish the right comfort level in each room.
--
Cheers,
Set Square
______
Please reply to newsgroup. Reply address is invalid.


  #7   Report Post  
IMM
 
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"Phil Addison" wrote in message
...
On Wed, 6 Oct 2004 12:24:05 +0100, "IMM" wrote:


"Simon Langford" wrote in message
om...
I'm having difficulting getting the radiators on the 2nd floor of our
house to heat up. My efforts have so far involved closing down the
LSVs almost completely on the hottest rads (kitchen area and ground
floor), leaving the LSVs wide open on the 2nd floor, and somewhere in
between on the 1st floor.

On balancing radiators, the FAQ says...

"The important thing is that the return water coming out of each
radiator is good and hot. If it's only warm you need to open its Lock
Shield Valve (LSV) some more, or if it's already wide open you have to
close the LSVs on the hottest radiators instead."

The problem is that the 2nd floor rads are still not hot (just warm),
and the ground and 1st floor rads now have cool return pipes. If I
open up the LSVs so get hot return pipes on the ground floor, then the
2nd floor rads are even less hot.

Do you think I need a bigger boiler (it's already a pretty big one)?
Or would a faster pump help?


Are the pipes large enough? Is there too many elbows rather than bends?


How do you expect the original poster to know the answer to that?


Erm, erm, it's his system.


  #8   Report Post  
Phil Addison
 
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On Wed, 6 Oct 2004 13:56:01 +0100, "IMM" wrote:

"Phil Addison" wrote in message
...

Do you think I need a bigger boiler (it's already a pretty big one)?
Or would a faster pump help?


Are the pipes large enough? Is there too many elbows rather than bends?


How do you expect the original poster to know the answer to that?


Erm, erm, it's his system.


Oh, so now you think that everyone that owns a central heating system is
capable of calculating the required pipe sizes. That's rich coming from
the one that refers to all diyers as incompetent.

And do try to remember to snip, there's a good chap.

Phil
The uk.d-i-y FAQ is at http://www.diyfaq.org.uk/
Remove NOSPAM from address to email me
  #9   Report Post  
Ed Sirett
 
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On Wed, 06 Oct 2004 04:14:24 -0700, Simon Langford wrote:

There are number of ways forward:

1) If the boiler is fires up and never stops on its own thermostat until
it's turned off then it simply is not powerful enough, or there is something
very wrong with it. This is possible but less likely than (2).

2) The pump is simply not pushing the water around hard enough. The boiler
is working fine, it gets hot and cuts in and out as needed but the water
is not moving around well enough for the number of radiators and size of
house and size of pipe work in your installation.

3) As (2) but the pump has become very ineffective - I have known pumps to
erode away in adverse circumstances.

Details of the make and model of boiler would be useful also is the pump
in the boiler or is it elsewhere. If the latter then it may well be a two
or 3 speed unit and all you have to do is turn it up a notch.

--
Ed Sirett - Property maintainer and registered gas fitter.
The FAQ for uk.diy is at www.diyfaq.org.uk
Gas fitting FAQ http://www.makewrite.demon.co.uk/GasFitting.html
Sealed CH FAQ http://www.makewrite.demon.co.uk/SealedCH.html


  #10   Report Post  
Jan Wysocki
 
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In article , Simon Langford wrote:
[snip]
The problem is that the 2nd floor rads are still not hot (just warm),
and the ground and 1st floor rads now have cool return pipes. If I
open up the LSVs so get hot return pipes on the ground floor, then the
2nd floor rads are even less hot.

Do you think I need a bigger boiler (it's already a pretty big one)?
Or would a faster pump help?


It seems suspicious that it's just the higher radiators that don't
get hot. Have you tried bleeding them to check that they're not
full of gas? Your central heating has presumably been idle all
summer and gas released by corrosion may have collected upstairs.

--
Jan


  #11   Report Post  
Simon Langford
 
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Phil Addison wrote in message . ..

Have you actually followed the detailed procedure, or is the above all
you have done?


I pretty much summed up all that I've done in my first para - i.e.
just closed down the LSVs on the hottest (ground floor) rads, hoping
that would force some hot water to make its way up to the second
floor. I've not done any proper temperature readings (except using my
hand!). All of the go/return plumbing is concealed below the
flooring, so I cannot tell how the plumbing is routed. There is about
a meter of exposed 'main' pipework near the boiler and I guess the
external diameter is about 25mm.


If you *have* followed the FAQ procedure, it seems that there is some
inadequacy in the plumbing design. To track this down, try the
following:

Turn off the boiler.
Open both valves fully on one radiator and close down all the others.
Turn boiler back on.

If that radiator heats up, repeat for each of the others in turn.


I tried that last night - with all the others locked off, my top rads
heat up nice and hot. So no blockages, airlocks, etc.


The boiler size would only be a problem if it is firing continuously
flat out and the radiators are still not getting all equally hot.


This does seem to be the case.


If that does not help you will need to give us much more details of the
system and what it is doing.


OK: I have 10 rads on the ground floor (double panels ranging from
50cm to 120cm, and a 200cm single panel), 2 on the first floor and 2
on the second floor. And a chrome towel rail on each floor. The
boiler is a Worcester Highflow 400, running off LPG (costs a
fortune!). It has an built-in pump which is not speed adjustable.
(The manual says "if there is a switch, it will be factory set to
maximum and should not be adjusted".)

The whole system was brand new about 18 months ago. I had the same
problem all last winter (we had to get electric heaters on the top
floor!). Surely whoever installed it would have used an adequate size
boiler? It's physically much bigger than in my last house -- and that
was a 3-storey house too. I wonder whether the problem is that there
are so many more rads on the ground floor than on the upper floors?

Thanks again,

Simon.
  #12   Report Post  
Dave Plowman (News)
 
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In article ,
Simon Langford wrote:
I wonder whether the problem is that there
are so many more rads on the ground floor than on the upper floors?


Please go through the balancing procedure described in the FAQ.

--
*Never slap a man who's chewing tobacco *

Dave Plowman London SW
To e-mail, change noise into sound.
  #13   Report Post  
IMM
 
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"Phil Addison" wrote in message
...
On Wed, 6 Oct 2004 13:56:01 +0100, "IMM" wrote:

"Phil Addison" wrote in message
...

Do you think I need a bigger boiler (it's already a pretty big

one)?
Or would a faster pump help?

Are the pipes large enough? Is there too many elbows rather than

bends?

How do you expect the original poster to know the answer to that?


Erm, erm, it's his system.


Oh, so now you think that everyone that owns a central heating system is
capable of calculating the required pipe sizes.


I'm sure he can tell us how much 22mm or 15mm there is.


  #14   Report Post  
John Laird
 
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On Thu, 07 Oct 2004 09:36:53 +0100, "Dave Plowman (News)"
wrote:

In article ,
Simon Langford wrote:
I wonder whether the problem is that there
are so many more rads on the ground floor than on the upper floors?


Please go through the balancing procedure described in the FAQ.


To be fair, I think the OP has made some steps in that direction. Where he
probably needs help is in judging the amount to open up the LSVs on the
lower radiators so as not to starve the upper-floor units of heat. I spent
some time re-balancing my system a couple of years ago, and was quite
surprised that some radiator valves literally only need to be open half a
turn (maybe even less), while others needed to be fully open. I didn't use
a thermometer, it has to be said. All my radiators have TRVs and I wasn't
entirely convinced that you can follow a rigid approach with one valve when
at the other end of the radiator there is another working all by itself (and
in general they are almost never fully open or closed but constantly
adjusting, especially during times when the water is heating up). Even now,
some radiators take a little longer than others to warm up, but once the
system is fully heated, they are heating about as evenly as I would want.

With the vast majority of the OP's radiators on the ground floor, these are
the ones that will, in the main, need to be virtually closed off. He does
have quite a large load but the boiler is spec'd at 24kW and ought to be
able to cope. Likewise, one would hope the boiler designers fitted a
suitable size pump integral pump.

--
We had a meeting of the minds but yours didn't show up.

Mail john rather than nospam...
  #15   Report Post  
Dave Plowman (News)
 
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In article ,
John Laird wrote:
Please go through the balancing procedure described in the FAQ.


To be fair, I think the OP has made some steps in that direction. Where
he probably needs help is in judging the amount to open up the LSVs on
the lower radiators so as not to starve the upper-floor units of heat.
I spent some time re-balancing my system a couple of years ago, and was
quite surprised that some radiator valves literally only need to be open
half a turn (maybe even less), while others needed to be fully open.


It's some time since I've read the FAQ, but isn't this covered in that?
Gate valves tend to be very non linear, as opposed to 'tap' types.

I didn't use a thermometer, it has to be said.


It makes life so much easier. And accurate DVMs that incorporate a
temperature probe are cheap these days - and will find more uses than a
pipe thermometer.

All my radiators have TRVs
and I wasn't entirely convinced that you can follow a rigid approach
with one valve when at the other end of the radiator there is another
working all by itself (and in general they are almost never fully open
or closed but constantly adjusting, especially during times when the
water is heating up). Even now, some radiators take a little longer
than others to warm up, but once the system is fully heated, they are
heating about as evenly as I would want.


I didn't believe just how important taking time to balance the system
properly was - thinking you could just rely on the TRVs. But if you want
the house to warm up evenly, it's vital.

With the vast majority of the OP's radiators on the ground floor, these
are the ones that will, in the main, need to be virtually closed off.


Yes.

He does have quite a large load but the boiler is spec'd at 24kW and
ought to be able to cope. Likewise, one would hope the boiler designers
fitted a suitable size pump integral pump.


But you need to key down the flow to the rads that are the offenders
before worrying about the pump. I've also got a three story house, and my
pump is set on minimum (out of three settings).

--
*Growing old is inevitable, growing up is optional *

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


  #16   Report Post  
Phil Addison
 
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On 7 Oct 2004 01:26:21 -0700, (Simon Langford)
wrote:

Phil Addison wrote in message news:
...

Have you actually followed the detailed procedure, or is the above all
you have done?


I pretty much summed up all that I've done in my first para - i.e.
just closed down the LSVs on the hottest (ground floor) rads, hoping
that would force some hot water to make its way up to the second
floor. I've not done any proper temperature readings (except using my
hand!). All of the go/return plumbing is concealed below the
flooring, so I cannot tell how the plumbing is routed. There is about
a meter of exposed 'main' pipework near the boiler and I guess the
external diameter is about 25mm.


Has it always been like this? If not, has anything been changed?

The 'about 25mm' pipe would either be 22mm or 28mm.

What diameter pipes connect to the rads on 2nd floor? If they are skinny
(8 or 10mm outside diameter) that is a likely cause, assuming you have
properly balanced the system. Even 15mm may be
pushing it depending on the length of run and size of the rads.

If that is the problem you just might be able to fix it with a more
powerful pump, but I wouldn't hold out much hope because if the pipes
are too skinny the resistance goes up *very* rapidly as you try to
increase the flow rate. The length limits for the runs are really pretty
firm, and if exceeded for a given heat load (i.e. radiator size), there
is not much alternative to replacing with a larger bore.

On the other hand it may be the pipes are OK, but you have one of the
other problems I mentioned.

If you *have* followed the FAQ procedure, it seems that there is some
inadequacy in the plumbing design. To track this down, try the
following:

Turn off the boiler.
Open both valves fully on one radiator and close down all the others.
Turn boiler back on.

If that radiator heats up, repeat for each of the others in turn.


I tried that last night - with all the others locked off, my top rads
heat up nice and hot. So no blockages, airlocks, etc.


That is a good indication (but only that) that it is just a balancing
problem. What you need to do now is *very* slightly crack open the LSV
on the downstairs rads to see if they can be got hot without
short-circuiting the upstairs loop. It is very important not to open the
LSV any more than what gives a hot downstairs radiator. Opening it too
much will give no additional benefit to that rad but will cause it to
bypass water that should be going to the upper floors.

As others have said, you do need to go further than these rough tests
and carefully follow the balancing procedure. I have high hopes that
that is all that is wrong. A £20 IR thermometer will be a great help to
speed up the process which is otherwise very tedious. If you use one, I
find a square of black PVC insulating tape stuck to the pipes to be an
excellent standard surface from which to measure the temperature.

The boiler size would only be a problem if it is firing continuously
flat out and the radiators are still not getting all equally hot.


This does seem to be the case.


Not sure what you mean. So far the rads are not balanced to equally
heat, so we cannot yet draw conclusions about the boiler.

If that does not help you will need to give us much more details of the
system and what it is doing.


OK: I have 10 rads on the ground floor (double panels ranging from
50cm to 120cm, and a 200cm single panel), 2 on the first floor and 2
on the second floor. And a chrome towel rail on each floor.


Don't forget the towel rails are rads that need balancing too. They can
also short-circuit the upper loops.

The boiler is a Worcester Highflow 400, running off LPG (costs a
fortune!). It has an built-in pump which is not speed adjustable.
(The manual says "if there is a switch, it will be factory set to
maximum and should not be adjusted".)

The whole system was brand new about 18 months ago. I had the same
problem all last winter (we had to get electric heaters on the top
floor!). Surely whoever installed it would have used an adequate size
boiler? It's physically much bigger than in my last house -- and that
was a 3-storey house too. I wonder whether the problem is that there
are so many more rads on the ground floor than on the upper floors?


Sounds like a typical installation where it is all carefully designed by
a heating engineer, and then installed by a plumber who has no idea of
the importance of balancing. In the groups experience, it seems that
virtually the only systems that get balanced are those done by DIYers.
It's probably not relevant here, but do you have a decent set of
controls? i.e. programmer, room stats, separate control over hot
water/central heating, and possibly ability to turn off
upstairs/downstairs zones?

If you can't get it balanced I should start raising hell with the
installer on the basis that it was never working to spec (e.g. to raise
rooms by about 24C over outside temp of -3C). This will be aided if you
can show charts of room temperature attained vs outside temp. The
inside/outside differential is roughly linear, so that if the rad in a
room raises it by 5C more than outside on a warm day, that is also what
it will do when it is -3C outside. So measure room temps and convert
them to what it will be when the outside is -3C and ask the installer
what he intends to do about it. These measurements should be with all
the room, TRVs and boiler stats turned to max.

Is the boiler producing very hot water at its flow, and with cool
returning water? If so the heat must be going somewhere, assuming the
pump is running!! Is it running? Can you hear it/feel it vibrating? Even
so it may still be damaged if any vanes are broken off inside. Take
the end cap off and see if the spindle is spinning - only an egg cup of
water will come out.

Phil

Phil
The uk.d-i-y FAQ is at
http://www.diyfaq.org.uk/
Remove NOSPAM from address to email me
  #18   Report Post  
Simon Langford
 
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Thanks for all the replies and help everyone. I think I'm getting
somewhere now. I screwed down all the radiators and towel rails apart
from the top floor and ran the boiler for 30 minutes. Sure enough the
top floor gets nice and hot.

Then I opened up the ground and first floors just a little bit, until
some warmth came through. This morning when the heating came on,
everything was nice and warm.

When I checked the pressure in the system before forcing the heat up
to the top floor, it was at 1 bar. After getting the top floor hot it
was down to almost zero, so maybe there was a blockage somewhere which
has now been shifted. I'm going to do a proper bleed tonight, and
might get myself a digital thermometer as recommended here, to do a
proper balance.

I'm still pretty sure that the boiler runs flat out (i.e. never cuts
out under its own thermostat). It is quite a large house, especially
the ground floor which is more than twice the area of the other floors
and has some very high ceilings. So maybe a 24KW boiler is only just
up to the job? We're about to remove a large radiator from the
kitchen and put a wood burning stove in its place, so that might help
the boiler load. (I know the kitchen will be colder when the stove's
not lit...)

Anyway, thanks for all the help.

Simon.
  #19   Report Post  
IMM
 
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"Simon Langford" wrote in message
om...
Thanks for all the replies and help everyone. I think I'm getting
somewhere now. I screwed down all the radiators and towel rails apart
from the top floor and ran the boiler for 30 minutes. Sure enough the
top floor gets nice and hot.

Then I opened up the ground and first floors just a little bit, until
some warmth came through. This morning when the heating came on,
everything was nice and warm.

When I checked the pressure in the system before forcing the heat up
to the top floor, it was at 1 bar. After getting the top floor hot it
was down to almost zero, so maybe there was a blockage somewhere which
has now been shifted. I'm going to do a proper bleed tonight, and
might get myself a digital thermometer as recommended here, to do a
proper balance.

I'm still pretty sure that the boiler runs flat out (i.e. never cuts
out under its own thermostat). It is quite a large house, especially
the ground floor which is more than twice the area of the other floors
and has some very high ceilings. So maybe a 24KW boiler is only just
up to the job? We're about to remove a large radiator from the
kitchen and put a wood burning stove in its place, so that might help
the boiler load. (I know the kitchen will be colder when the stove's
not lit...)

Anyway, thanks for all the help.

Simon.


If the boiler is borderline install extra insulation in the loft. Then go
around with a silicon gun and get rid of air leaks.


  #20   Report Post  
Dave Plowman (News)
 
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In article ,
IMM wrote:
If the boiler is borderline install extra insulation in the loft.


But only if the boiler is borderline?

Then go around with a silicon gun and get rid of air leaks.


Absolutely. Seal up all doors windows and airbricks. Haven't had any posts
on condensation yet.

--
* I like you. You remind me of when I was young and stupid

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


  #21   Report Post  
Phil Addison
 
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On 8 Oct 2004 02:45:03 -0700, (Simon Langford)
wrote:

Then I opened up the ground and first floors just a little bit, until
some warmth came through. This morning when the heating came on,
everything was nice and warm.


That's promising.

When I checked the pressure in the system before forcing the heat up
to the top floor, it was at 1 bar. After getting the top floor hot it
was down to almost zero, so maybe there was a blockage somewhere which
has now been shifted.


Checkout Ed Sirrets combi/Sealed System FAQ.

I'm going to do a proper bleed tonight, and
might get myself a digital thermometer as recommended here, to do a
proper balance.


Having tried the digital multi-meter thermocouple type, and the 'pocket'
IR type, I can assure you that the IR type makes the task an order of
magnitude easier. I can't find the one I have online anymore, but these
two look similar
http://www.thermometersdirect.co.uk/item257.htm
http://www.mh-1.com/ordering.htm

I'm still pretty sure that the boiler runs flat out (i.e. never cuts
out under its own thermostat). It is quite a large house, especially
the ground floor which is more than twice the area of the other floors
and has some very high ceilings. So maybe a 24KW boiler is only just
up to the job?


A google search for Andy Hall's posts on calculating what the radiator
(and hence boiler) sizes should get you the info you need to check it
out.

With an undersized boiler, accurate balancing is even more important to
get the best of what you have. If the boiler is undersized, you probably
will end up with a larger temp drop across the rads than the oft quoted
11C; that doesn't matter - what is important is to get the same drop
across each rad.

We're about to remove a large radiator from the
kitchen and put a wood burning stove in its place, so that might help
the boiler load. (I know the kitchen will be colder when the stove's
not lit...)


I have a friend who managed to connect a wood-burning stove (with back
boiler) in parallel with his central heating boiler.

Phil
The uk.d-i-y FAQ is at http://www.diyfaq.org.uk/
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  #22   Report Post  
Dave Plowman (News)
 
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In article ,
Phil Addison wrote:
Having tried the digital multi-meter thermocouple type, and the 'pocket'
IR type, I can assure you that the IR type makes the task an order of
magnitude easier.


Is it as versatile, though? Maplin do a DVM with temp probe for about a
tenner, and a DVM has many other uses too (if you haven't already got one).

Can you also the temperature of a domestic oven with the IR type? It's
nice to know just how far out a new one actually is...

--
*A plateau is a high form of flattery.*

Dave Plowman London SW
To e-mail, change noise into sound.
  #23   Report Post  
Richard Porter
 
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On 8 Oct 2004 "Dave Plowman (News)" wrote:

In article ,
IMM wrote:
If the boiler is borderline install extra insulation in the loft.


But only if the boiler is borderline?

Then go around with a silicon gun and get rid of air leaks.


Absolutely. Seal up all doors windows and airbricks. Haven't had any posts
on condensation yet.


Quite right! Make sure that absolutely NO OXYGEN can get into the house.
Then light the gas fire or a gas ring if you haven't got a fire. This
should burn off the remaining oxygen and generate lots of carbon
monoxide. After that you should have no further problems.

Unfortunately your next of kin may.

--
Richard Porter
Mail to username ricp at domain minijem.plus.com
"You can't have Windows without pains."
  #24   Report Post  
nick smith
 
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When I checked the pressure in the system before forcing the heat up
to the top floor, it was at 1 bar. After getting the top floor hot it
was down to almost zero, so maybe there was a blockage somewhere which
has now been shifted.


If the pressure is 1 bar at ground level, you would EXPECT zero pressure 30
feet up - is it a 3 floor house ?

Nick


  #25   Report Post  
John Laird
 
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On Fri, 08 Oct 2004 15:21:11 GMT, "nick smith" wrote:

When I checked the pressure in the system before forcing the heat up
to the top floor, it was at 1 bar. After getting the top floor hot it
was down to almost zero, so maybe there was a blockage somewhere which
has now been shifted.


If the pressure is 1 bar at ground level, you would EXPECT zero pressure 30
feet up - is it a 3 floor house ?


I've never been quite sure what effect a pump has. If the gauge is "behind"
the pump, would a drop from the static pressure be expected ? This drop
from 1 bar to nearly zero confused me. It only seems to make sense if the
pressure behind the pump *can* fall, in which case what the OP is observing
is the pump working harder than before, trying to push the water around the
upper floor pipework. (We've exchanged emails and apparently all the
inter-floor plumbing is hidden from sight, but I suspect too much has been
run in 15mm.)

--
The current death rate? One per person, of course.

Mail john rather than nospam...


  #26   Report Post  
IMM
 
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"Richard Porter" wrote in message
...
On 8 Oct 2004 "Dave Plowman (News)" wrote:

In article ,
IMM wrote:
If the boiler is borderline install extra insulation in the loft.


But only if the boiler is borderline?

Then go around with a silicon gun and get rid of air leaks.


Absolutely. Seal up all doors windows and airbricks. Haven't had any

posts
on condensation yet.


Quite right! Make sure that absolutely NO OXYGEN can get into the house.
Then light the gas fire or a gas ring if you haven't got a fire. This
should burn off the remaining oxygen and generate lots of carbon
monoxide. After that you should have no further problems.

Unfortunately your next of kin may.


Some mothers.....


  #27   Report Post  
Phil Addison
 
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On Fri, 08 Oct 2004 13:38:01 +0100, "Dave Plowman (News)"
wrote:

In article ,
Phil Addison wrote:
Having tried the digital multi-meter thermocouple type, and the 'pocket'
IR type, I can assure you that the IR type makes the task an order of
magnitude easier.


Is it as versatile, though? Maplin do a DVM with temp probe for about a
tenner, and a DVM has many other uses too (if you haven't already got one).


Horses for courses! I have several multi-meters, 1 of which has a
thermocouple K-bead on a flying lead , and a maplin food probe.

The maplin probe was great for checking the core temp of a joint of beef
but when I tried to monitor the meat as it cooked in the oven the lead
melted!! Seems the probe was good for 200C or so, but not the flex
cable. Doh!!

The thermocouple K-bead is accurate in melting ice and boiling water,
but its not very good at measuring surface temperature because of the
difficulty of getting good thermal and mechanical contact between a tiny
near spherical bead and e.g. a grubby 15mm pipe. Before I had my IR that
is what I used for balancing with a 'clever' arrangement of rubber and
aluminium foil glued into a giant clothes peg. It takes time (lots of
it) to rig that onto the pipe of a radiator and then to repeat it on the
other side, not to mention backache - all that kneeling down and up
again.

With the IR, I at first could not get consistent readings, depended
exactly which bit of pipe you pointed it at, or at the chrome valve etc.
In the end I went for the black emitter idea and stuck a square of black
PVC insulating tape to each flow and return pipe just below the valves.
With that I get the same reading each time and it is quick. I can run
round the house with a clipboard and the IR meter measuring each of the
14 rads in 1/4hr or so.

Can you also the temperature of a domestic oven with the IR type? It's
nice to know just how far out a new one actually is...


Sort of. It measures surface temperatures not air temp so you have to
open the oven and point it at the hot walls, and no, it won't work
through the glass door. I use the thermocouple K-bead DVM for the oven -
it measures the air temp and its flex seems to stand up to the heat, and
is thin enough to close the oven door on it.

Phil
The uk.d-i-y FAQ is at http://www.diyfaq.org.uk/
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  #28   Report Post  
Phil Addison
 
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On Fri, 08 Oct 2004 17:57:37 +0100, John Laird
wrote:

On Fri, 08 Oct 2004 15:21:11 GMT, "nick smith" wrote:

When I checked the pressure in the system before forcing the heat up
to the top floor, it was at 1 bar. After getting the top floor hot it
was down to almost zero, so maybe there was a blockage somewhere which
has now been shifted.

If the pressure is 1 bar at ground level, you would EXPECT zero pressure 30
feet up - is it a 3 floor house ?


Surely this is the reading on the boiler gauge?

I've never been quite sure what effect a pump has. If the gauge is "behind"
the pump, would a drop from the static pressure be expected ? This drop
from 1 bar to nearly zero confused me. It only seems to make sense if the
pressure behind the pump *can* fall, in which case what the OP is observing
is the pump working harder than before, trying to push the water around the
upper floor pipework.


The static pressure will not be affected by the pump. That only affects
the... err... dynamic pressure. Think of a closed circuit consisting of
a battery and bulb, and float this from one terminal of another battery.
Switching on the bulb doesn't affect the voltage of the other battery.

I think its more likely that Simon has lost pressure in the system,
perhaps due to bleeding a radiator. Ed Sirret's Sealed Heating System
FAQ http://www.makewrite.demon.co.uk/SealedCH.html explains what to do
in that case.

(We've exchanged emails and apparently all the
inter-floor plumbing is hidden from sight, but I suspect too much has been
run in 15mm.)


Or even 10mm. What diameter pipe emerges to feed the rads?

Phil
The uk.d-i-y FAQ is at http://www.diyfaq.org.uk/
Remove NOSPAM from address to email me
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IMM
 
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"Richard Porter" wrote in message
...
On 8 Oct 2004 "Dave Plowman (News)" wrote:

In article ,
IMM wrote:
If the boiler is borderline install extra insulation in the loft.


But only if the boiler is borderline?

Then go around with a silicon gun and get rid of air leaks.


Absolutely. Seal up all doors windows and airbricks. Haven't had any

posts
on condensation yet.


Quite right! Make sure that absolutely NO OXYGEN can get into the house.
Then light the gas fire or a gas ring if you haven't got a fire. This
should burn off the remaining oxygen and generate lots of carbon
monoxide. After that you should have no further problems.

Unfortunately your next of kin may.


Air leakage may be 30-50% of a typical fuel bill. The Canadians say "built
tight ventilate right" Very simple really.




  #31   Report Post  
Andy Wade
 
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Ed Sirett wrote:

1) If the boiler is fires up and never stops on its own thermostat until
it's turned off then it simply is not powerful enough, [...]


Unless of course it has a modulating burner.

--
Andy
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