I want to modify the pipework feeding a radiator on a combi boiler system
but I could do with some advice on how to go about it as I am a novice at CH
systems.

My idea was to use a couple of freezer kits that go around the pipe
isolating the section, avoiding draining down the whole system. I havn't
used these kits before, but guess that it is best to release the pressure in
the system before starting. If I shut the water off at the house stopcock
and open a radiator vent valve, will this be suffiencient to release the
pressure in the system? I'm thinking about air stored somewhere - in a
closed header tank?

When the pipework changes are done, are there any potential problems
about getting any lost corrosion protection fluid / antifreeze back in - and
getting any air out of the system to restore normal operation?

Thanks.

Roger R

On Tue, 18 Nov 2008 16:31:03 -0000, "Roger R"
wrote:

I want to modify the pipework feeding a radiator on a combi boiler system
but I could do with some advice on how to go about it as I am a novice at CH
systems.

My idea was to use a couple of freezer kits that go around the pipe
isolating the section, avoiding draining down the whole system. I havn't
used these kits before, but guess that it is best to release the pressure in
the system before starting. If I shut the water off at the house stopcock
and open a radiator vent valve, will this be suffiencient to release the
pressure in the system? I'm thinking about air stored somewhere - in a
closed header tank?

When the pipework changes are done, are there any potential problems
about getting any lost corrosion protection fluid / antifreeze back in - and
getting any air out of the system to restore normal operation?

Thanks.

Roger R

I have a thread somewhere up there ..around the 9th of Nov...for a
similar situation 'cept I'm replacing a rad . I've done everything
except connect up the new pipes ( the rad is a different size) and
what I am going to do is shut off the boiler ( Combi sealed system)
,close off all the others rads incl using decorators caps,drain down
the pipework ,cut the pipes to the old rad and join the new piping
then close the drain tap,fill up using the filling loop having added
some additional Sentinel and bleed the system .

In article ,
Roger R wrote:
I want to modify the pipework feeding a radiator on a combi boiler
system but I could do with some advice on how to go about it as I am a
novice at CH systems.

My idea was to use a couple of freezer kits that go around the pipe
isolating the section, avoiding draining down the whole system.

Why? If it's difficult to drain at the moment because of a poorly
positioned drain now's the time to sort that.

It sounds like you're not terribly experienced and those freezer thingies
cost a lot and of course soon melt. Just what you need half way through
the job. And it would be a good time to add new inhibitor as well.

I havn't used these kits before, but guess that it is best to release
the pressure in the system before starting. If I shut the water off at
the house stopcock and open a radiator vent valve, will this be
suffiencient to release the pressure in the system? I'm thinking about
air stored somewhere - in a closed header tank?

If it's a sealed system their should be no water feed to it anyway. The
filling loop should be disconnected after use. If an open one with header
tank there should be a stopcock - or you could tie up the ball valve.

When the pipework changes are done, are there any potential problems
about getting any lost corrosion protection fluid / antifreeze back in -
and getting any air out of the system to restore normal operation?

Pressurized systems don't normally airlock so are just bled in the usual
way. Best to do all this and make sure there are no leaks on the new work
before partial draining down again to add inhibitor. The normal way is to
use concentrate and a gun - same as the ones for sealers - and the
concentrate should come with an adaptor tube to feed in via a bleed screw.

--
*Gargling is a good way to see if your throat leaks.

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

On Tue, 18 Nov 2008 16:58:35 +0000 (GMT), "Dave Plowman (News)"
wrote:

In article ,
Roger R wrote:
I want to modify the pipework feeding a radiator on a combi boiler
system but I could do with some advice on how to go about it as I am a
novice at CH systems.

My idea was to use a couple of freezer kits that go around the pipe
isolating the section, avoiding draining down the whole system.

Why? If it's difficult to drain at the moment because of a poorly
positioned drain now's the time to sort that.

It sounds like you're not terribly experienced and those freezer thingies
cost a lot and of course soon melt. Just what you need half way through
the job. And it would be a good time to add new inhibitor as well.

I havn't used these kits before, but guess that it is best to release
the pressure in the system before starting. If I shut the water off at
the house stopcock and open a radiator vent valve, will this be
suffiencient to release the pressure in the system? I'm thinking about
air stored somewhere - in a closed header tank?



If it's a sealed system their should be no water feed to it anyway. The
filling loop should be disconnected after use.

I've seen this mentioned a few places but never seen an explanation as
to why it need be removed . It was connected on my Alpha when it came
out of the box and has styed in situ ever since .The fitter made no
mention of removing it ....not sure what the manual says ( must look)
but surely if the taps in the loop are in the off position thats good
enough . Seems more convenient to have it connected rather than
faffing about anytime u need to topup ..even if it is a rare occasion.
Anyone know?

In article ,
wrote:
If it's a sealed system their should be no water feed to it anyway. The
filling loop should be disconnected after use.

I've seen this mentioned a few places but never seen an explanation as
to why it need be removed . It was connected on my Alpha when it came
out of the box and has styed in situ ever since .The fitter made no
mention of removing it ....not sure what the manual says ( must look)
but surely if the taps in the loop are in the off position thats good
enough . Seems more convenient to have it connected rather than
faffing about anytime u need to topup ..even if it is a rare occasion.
Anyone know?

I'd say it's just to prevent the mains water being left on.

--
*24 hours in a day ... 24 beers in a case ... coincidence? *

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

"Dave Plowman (News)" wrote in message
...
In article ,
wrote:
If it's a sealed system their should be no water feed to it anyway. The
filling loop should be disconnected after use.

I've seen this mentioned a few places but never seen an explanation as
to why it need be removed . It was connected on my Alpha when it came
out of the box and has styed in situ ever since .The fitter made no
mention of removing it ....not sure what the manual says ( must look)
but surely if the taps in the loop are in the off position thats good
enough . Seems more convenient to have it connected rather than
faffing about anytime u need to topup ..even if it is a rare occasion.
Anyone know?

I'd say it's just to prevent the mains water being left on.

If a tap is left on a little, the system could continue to fill without
being noticed. If you get the habit of disconnecting the fill loop after
topping up, you notice quicker that a tap has been left on, at either end of
the fill loop.

On Tue, 18 Nov 2008 17:33:02 GMT, "BigWallop"
wrote:


"Dave Plowman (News)" wrote in message
...
In article ,
wrote:
If it's a sealed system their should be no water feed to it anyway. The
filling loop should be disconnected after use.

I've seen this mentioned a few places but never seen an explanation as
to why it need be removed . It was connected on my Alpha when it came
out of the box and has styed in situ ever since .The fitter made no
mention of removing it ....not sure what the manual says ( must look)
but surely if the taps in the loop are in the off position thats good
enough . Seems more convenient to have it connected rather than
faffing about anytime u need to topup ..even if it is a rare occasion.
Anyone know?

I'd say it's just to prevent the mains water being left on.

If a tap is left on a little, the system could continue to fill without
being noticed. If you get the habit of disconnecting the fill loop after
topping up, you notice quicker that a tap has been left on, at either end of
the fill loop.



So it's advice for idiots then .That's what I suspected . :-)

wrote in message
...
snipped

I'd say it's just to prevent the mains water being left on.

If a tap is left on a little, the system could continue to fill without
being noticed. If you get the habit of disconnecting the fill loop
after
topping up, you notice quicker that a tap has been left on, at either end
of
the fill loop.



So it's advice for idiots then .That's what I suspected . :-)


Literally, yes. :-) But with those little flappy paddle taps, it is
possible to leave one on a little. The same happened to me with a washing
machine valve. Just didn't tighten the tap off as much as I should have.
The tiny drip, and it was tiny, over a week of being left unattended, didn't
do the wooden floor much good. :-((

On Tue, 18 Nov 2008 18:03:03 GMT, "BigWallop"
wrote:


wrote in message
.. .
snipped

I'd say it's just to prevent the mains water being left on.

If a tap is left on a little, the system could continue to fill without
being noticed. If you get the habit of disconnecting the fill loop
after
topping up, you notice quicker that a tap has been left on, at either end
of
the fill loop.



So it's advice for idiots then .That's what I suspected . :-)


Literally, yes. :-) But with those little flappy paddle taps, it is
possible to leave one on a little. The same happened to me with a washing
machine valve. Just didn't tighten the tap off as much as I should have.
The tiny drip, and it was tiny, over a week of being left unattended, didn't
do the wooden floor much good. :-((


No it wouldn't ....I have a wooden floor immediately below my boiler
so if I took the loop off and there was drip from the tap my floor
would get it .However the boiler is right next to the sink so a glance
across daily can tell me if the pressure is going past where it
should be ....altho' it won't be cos the taps are def OFF :-)

wrote in message
...
On Tue, 18 Nov 2008 17:33:02 GMT, "BigWallop"
wrote:


"Dave Plowman (News)" wrote in message
...
In article ,
wrote:
If it's a sealed system their should be no water feed to it anyway.
The
filling loop should be disconnected after use.

I've seen this mentioned a few places but never seen an explanation as
to why it need be removed . It was connected on my Alpha when it came
out of the box and has styed in situ ever since .The fitter made no
mention of removing it ....not sure what the manual says ( must look)
but surely if the taps in the loop are in the off position thats good
enough . Seems more convenient to have it connected rather than
faffing about anytime u need to topup ..even if it is a rare occasion.
Anyone know?

I'd say it's just to prevent the mains water being left on.

If a tap is left on a little, the system could continue to fill without
being noticed. If you get the habit of disconnecting the fill loop after
topping up, you notice quicker that a tap has been left on, at either end
of
the fill loop.



So it's advice for idiots then .That's what I suspected . :-)



I think it is also to comply with regulations - you wouldn't want your C/H
water back feeding into the water mains if the mains pressure fell.


Incidentally - back to the pint - Will the system the OP has have an
accumulator - air pressure thing. If so some water will still be under
pressure when it is isolated.

wrote in message
...


So it's advice for idiots then .That's what I suspected . :-)

Probably.. there is the little thing about expansion and a filler loop is
stopped at both ends so if the temp changes it may become stressed depending
on what its made from.

On Tue, 18 Nov 2008 16:31:03 -0000 someone who may be "Roger R"
wrote this:-

I want to modify the pipework feeding a radiator on a combi boiler system
but I could do with some advice on how to go about it as I am a novice at CH
systems.

My idea was to use a couple of freezer kits that go around the pipe
isolating the section, avoiding draining down the whole system.

I would advise not using these kits by novices, who tend to work
slowly and may come to a sudden stop when they discover the bit they
have forgotten. It is not good to then be worrying about the ice
plugs melting.

I suggest draining down the whole system, as had been said this is
the time to fit drain points to make future work easier. If
necessary you can then put in a system cleanser (if you don't know
the history of the system), then inhibitor. These can be put into
radiators with a suitable gadget, there should be instructions with
the bottle it comes in. To take one example,
http://www.screwfix.com/prods/84838/Plumbing/Central-Heating-Treatment/No-Nonsense-Cleaner-1Ltr
comes with a little pipe which fits into a radiator.


--
David Hansen, Edinburgh
I will *always* explain revoked encryption keys, unless RIP prevents me
http://www.opsi.gov.uk/acts/acts2000/00023--e.htm#54

"Roger R" wrote in message
...
I want to modify the pipework feeding a radiator on a combi boiler system
but I could do with some advice on how to go about it as I am a novice at
CH
systems.

My idea was to use a couple of freezer kits that go around the pipe
isolating the section, avoiding draining down the whole system. I havn't
used these kits before, but guess that it is best to release the pressure
in
the system before starting. If I shut the water off at the house
stopcock
and open a radiator vent valve, will this be suffiencient to release the
pressure in the system? I'm thinking about air stored somewhere - in a
closed header tank?

When the pipework changes are done, are there any potential problems
about getting any lost corrosion protection fluid / antifreeze back in -
and
getting any air out of the system to restore normal operation?

Thanks.

Roger R

You shouldn't need to turn off the main house stopcock, as the radiator
water is not permanently fed from the mains supply.

You boiler probably has an expansion vessel inside it, so if you can isolate
the central heating pipes at the boiler, then do it. - make sure your boiler
is off during this work!)

Now, where is it you will be cutting the pipe? Assuming you are!
If it is under a floor, I would just use a pipe slice and cut the pipe, then
shove a push fit (reusable) end stop on the end - water loss should be
minimal (last time I did it, it was probably less than 1/4 litre)

If you plan to solder the pipe, then this won't work, as it needs to be
dry - if you are going to use push fit fittings, then this should be really
easy!

If you don't fancy doing it like this, then you need to drain the pipe work
(not the whole system)

To do this, you need to go round and turn off all the radiators you don't
want to drain (Including turning off the lockshield valves, but make sure
you make a note of how many turns that are set to now, so you can out them
back as they were.

Now isolate the CH pipes at the boiler if you can.

Now open your drain valve(s)

When the water stops (or almost stops) go and undo the bleed screw on and
radiators you need to drain (You may not need to drain any, in which case,
undo the nut on the pipe entering the radiator you are working on (on the
pipe side) a little (you should hear air being sucked in)

If you are altering the other pipe on this radiator, do the same to this.

now your pipe work should be mostly drained, so you can disconnect the pipe
fully.

If you blow down the pipe hard, this will expel any remaining water!


Complete you alterations and reconnect the radiator


Now to refill...

Close the drain taps!

make sure all your connection are tight

if you drained the radiator, close both valves now

If you isolated the boiler, go and open one of the valves.

Go to your radiator and open the bleed screw

open the lockshield valve, and observe if it hisses at you
If it doesn't, close the lockshield, and open the other valve

If it still doesn't, then the boiler has lost pressure, and needs to be
re-pressured - open the other valve on the boiler, and then partially
pressure the boiler using the filling loop (So, say 0.5 bar)

now go back to your radiator and open the lockshield - it should hiss this
time!
Close the lockshield and do the same with the other valve, then close it
again

Check for leaks in you new pipes

If it stops hissing, before water emerges from the bleed valve, close the
lockshield again, and go and re-pressure the boiler using the filling loop

Again, keep checking for leaks in you new pipes!

repeat until water squirts from the bleed screw.

Now bring the pressure up to 1.5 bar (Or whatever is normal on your system),
and check for leaks in the pipe work you have altered

Check the pressure again, and refill if required

If you can run the pump up on the boiler, without firing, then do this for 5
minutes or so, turn the boiler off again, then bleed the radiator you are
working on (leave all the others off for now) If not just turn on the
boiler, but keep the thermostat on the boiler low.

Go round and reset all the radiator valves back to their original positions.

check the pressure and top up if required

Run the boiler again for 10 minutes (pump only if you can, or just on low)

Go round and bleed all the radiators (there shouldn't be much air in them,
but there may be a bit!)

Job done.

Toby...

wrote in message
...
On Tue, 18 Nov 2008 17:33:02 GMT, "BigWallop"
wrote:


"Dave Plowman (News)" wrote in message
...
In article ,
wrote:
If it's a sealed system their should be no water feed to it anyway.
The
filling loop should be disconnected after use.

I've seen this mentioned a few places but never seen an explanation
as
to why it need be removed . It was connected on my Alpha when it came
out of the box and has styed in situ ever since .The fitter made no
mention of removing it ....not sure what the manual says ( must look)
but surely if the taps in the loop are in the off position thats good
enough . Seems more convenient to have it connected rather than
faffing about anytime u need to topup ..even if it is a rare
occasion.
Anyone know?

I'd say it's just to prevent the mains water being left on.

If a tap is left on a little, the system could continue to fill without
being noticed. If you get the habit of disconnecting the fill loop
after
topping up, you notice quicker that a tap has been left on, at either end
of
the fill loop.



So it's advice for idiots then .That's what I suspected . :-)

Not advice for idiots but water regulations. When disconnected it is not
possible for contaminated water to backflow into mains water system.

This will be shown in the installation instructions.

On Tue, 18 Nov 2008 22:53:22 -0000, "Heliotrope Smith"
wrote:


wrote in message
.. .
On Tue, 18 Nov 2008 17:33:02 GMT, "BigWallop"
wrote:


"Dave Plowman (News)" wrote in message
...
In article ,
wrote:
If it's a sealed system their should be no water feed to it anyway.
The
filling loop should be disconnected after use.

I've seen this mentioned a few places but never seen an explanation
as
to why it need be removed . It was connected on my Alpha when it came
out of the box and has styed in situ ever since .The fitter made no
mention of removing it ....not sure what the manual says ( must look)
but surely if the taps in the loop are in the off position thats good
enough . Seems more convenient to have it connected rather than
faffing about anytime u need to topup ..even if it is a rare
occasion.
Anyone know?

I'd say it's just to prevent the mains water being left on.

If a tap is left on a little, the system could continue to fill without
being noticed. If you get the habit of disconnecting the fill loop
after
topping up, you notice quicker that a tap has been left on, at either end
of
the fill loop.



So it's advice for idiots then .That's what I suspected . :-)

Not advice for idiots but water regulations. When disconnected it is not
possible for contaminated water to backflow into mains water system.

This will be shown in the installation instructions.


Oh Yeah....Regulations....regulations...regulations. You always keep
to rules do you :-)
This damn Country is overrun with regulations and this is one that I
am going to continue to ignore .

In article ,
wrote:
Not advice for idiots but water regulations. When disconnected it is
not possible for contaminated water to backflow into mains water system.

This will be shown in the installation instructions.


Oh Yeah....Regulations....regulations...regulations. You always keep
to rules do you :-)
This damn Country is overrun with regulations and this is one that I
am going to continue to ignore .

Trouble is you might contaminate other's drinking water too - not just
yours. Unlikely I know. Of course if you want to drink water that's been
lying around in your boiler etc for ages and mixed with gawd knows what
that's your business.

--
*If tennis elbow is painful, imagine suffering with tennis balls *

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

"Dave Plowman (News)" wrote in message
...
It sounds like you're not terribly experienced and those freezer thingies
cost a lot and of course soon melt. Just what you need half way through
the job. And it would be a good time to add new inhibitor as well.

Thanks for your comments.

I'll take the advice, avoiding the freezer kit and drain down the rad.

I now understand about the filling loop and how it is used, that it is
unnecessary to shut off the water main stop cock while doing the job, which
will enable refreshments to be available at intervals.

Incidently the boiler is in the garage and the rad is upstairs in the
bathroom, so that proabably makes it a bit simpler.

Inhibitor in tubes. I noticed them in the DIY shed today.

Roger R

I would advise not using these kits by novices, who tend to work
slowly and may come to a sudden stop when they discover the bit they
have forgotten. It is not good to then be worrying about the ice
plugs melting.

You strike a chord there as I often find the necessity to visit the diy shed
in the middle of a job.

I suggest draining down the whole system, as had been said this is
the time to fit drain points to make future work easier. If
necessary you can then put in a system cleanser (if you don't know
the history of the system), then inhibitor. These can be put into
radiators with a suitable gadget, there should be instructions with
the bottle it comes in.

The boiler is in the garage and the rad to be worked on is in the upstairs
bathroom. I will probably be able to just drain that one down without
needing to drain the whole system as it is quite recent, no more than two
years old.

Roger R

"Toby" wrote in message
...
You shouldn't need to turn off the main house stopcock, as the radiator
water is not permanently fed from the mains supply.

Job done.


Many thanks for your comprehensive step by step guide.

The boiler is a modern but not current Worcester Bosch located in the
garage. It's only been in about two years.

The rad in question is upstairs in the bathroom, and as I intend to cut
the pipes, I'll close the valves on the others to minimise loss and drain
it down.

Thanks again for your effort in typing out all the steps.

Roger R

wrote in message
...

I have a thread somewhere up there ..around the 9th of Nov...

Thanks for your reply.
I looked up your thread and saw the helpful response by Roger Mills.
That post and those received here seem to cover all the bases.

Roger R

Roger R wrote:
"Toby" wrote in message
...
You shouldn't need to turn off the main house stopcock, as the
radiator water is not permanently fed from the mains supply.

Job done.


Many thanks for your comprehensive step by step guide.

The boiler is a modern but not current Worcester Bosch located in the
garage. It's only been in about two years.

The rad in question is upstairs in the bathroom, and as I intend to
cut the pipes, I'll close the valves on the others to minimise loss
and drain it down.

Thanks again for your effort in typing out all the steps.

Roger R

No probs - Just to add to what I said, before about cutting it "live"
without draining down if it is under the floor, this only applies if it is
on the ground floor, not upstairs! as you don't want spill water where there
is a room below!

I would recommend you purchase at least two push fit end stops for the size
pipe you are cutting (reusable ones like this
http://www.screwfix.com/prods/24331
then if you have an emergency, and water starts to come out in large
quantities, you can just shove it on the end to stop it.

Make sure you get demountable ones, as some of them will go on, but need to
be cut off!

Put an old (large) towel down under where you are cutting, just in case you
haven't drained it down fully, and get a surprise!

The best pipe cutter I have used is a pipe slice like this
http://www.screwfix.com/prods/29457

I have also got one a bit like this
http://www.screwfix.com/prods/84140
But it is more awkward to use, and requires FAR more space around the pipe
you are cutting, so I would defiantly recommend the pipe slice cutters.

You say it is in a bathroom - it is a normal radiator, or a towel rail?
If it's a towel rail, it will probably have a cap on the top like this
http://www.ultimatehandyman.co.uk/to...leed_screw.jpg

If so, then the whole "nut" can be removed, to pour in the inhibitor with a
funnel - this will save having to "inject" it, and will probably be cheaper.

Even if it is not a towel rail, you may have a radiator in the house with a
similar cap on the side - just attach a short length of hose to the funnel,
and stick the other end in here to add the inhibitor (after draining a
suitable amount of water from the radiator first, of course!)

Toby...

"Roger R" wrote in message
...

"Toby" wrote in message
...
You shouldn't need to turn off the main house stopcock, as the radiator
water is not permanently fed from the mains supply.

Job done.


Many thanks for your comprehensive step by step guide.

The boiler is a modern but not current Worcester Bosch located in the
garage. It's only been in about two years.

The rad in question is upstairs in the bathroom, and as I intend to cut
the pipes, I'll close the valves on the others to minimise loss and drain
it down.

Thanks again for your effort in typing out all the steps.

Get your wet/dry vac out before you start.
They will vac up any spills before they can go anywhere.
I had to replace the washer on a drain cock last week and the aqua vac meant
I didn't get everything wet while completely unscrewing the plug and
removing it.
The wife moaned about having to hold her finger over the hole though while I
was putting the new washer on its post so I will have to find a cork next
time.