I need to add a couple of tees to a sealed central heating system.

It is a large one with more than 400 litres of water in it.

I am thinking of leaving some large radiators full of water by closing both valves in each of them and drain the rest of the system. Then cut the pipes and solder.

By leaving some radiators full of water I save time (shorter draining, less venting etc.), water and inhibitor.

Can this be done or will I run the risk of unexpected water ruining the soldering?

On 2 Oct, 18:28, asalcedo wrote:
I need to add a couple of tees to a sealed central heating system.

It is a large one with more than 400 litres of water in it.

I am thinking of leaving some large radiators full of water by closing
both valves in each of them and drain the rest of the system. Then cut
the pipes and solder.

By leaving some radiators full of water I save time (shorter draining,
less venting etc.), water and inhibitor.

Can this be done or will I run the risk of unexpected water ruining the
soldering?

--
asalcedo

I did this a little while ago by freezing the pipes. I looked at the
kit you can buy from B&Q and when I had recovered from the shock of
seeing the price I had a think and wondered if you could do the same
thing with butane. I ended up buying a few tins of butane for 60p each
from a cheap shop and then wrapping the pipe in old socks, making a
pipe from a length of thin copper tube and injecting the butane into
the sock. I have a temperature probe, bought for cooking, and within a
minute or two the temperature was -15C. I know it is obvious, but I
suppose I ought to say it, if you try this makes sure it is well
ventilated and no naked flames etc. etc. It got so bloody cold that I
reckon it would have stayed frozen for a couple of hours, especially
if it was wrapped in silver foil.

wrote in message
...
On 2 Oct, 18:28, asalcedo wrote:
I need to add a couple of tees to a sealed central heating system.

It is a large one with more than 400 litres of water in it.

I am thinking of leaving some large radiators full of water by closing
both valves in each of them and drain the rest of the system. Then cut
the pipes and solder.

By leaving some radiators full of water I save time (shorter draining,
less venting etc.), water and inhibitor.

Can this be done or will I run the risk of unexpected water ruining the
soldering?

--
asalcedo

I did this a little while ago by freezing the pipes. I looked at the
kit you can buy from B&Q and when I had recovered from the shock of
seeing the price I had a think and wondered if you could do the same
thing with butane. I ended up buying a few tins of butane for 60p each
from a cheap shop and then wrapping the pipe in old socks, making a
pipe from a length of thin copper tube and injecting the butane into
the sock. I have a temperature probe, bought for cooking, and within a
minute or two the temperature was -15C. I know it is obvious, but I
suppose I ought to say it, if you try this makes sure it is well
ventilated and no naked flames etc. etc. It got so bloody cold that I
reckon it would have stayed frozen for a couple of hours, especially
if it was wrapped in silver foil.

You can probably get cold enough by mixing salt and crushed ice.. its
cheaper than butane and probably safer.
You need at least as much ice as the quantity of water you need to freeze so
don't think a couple of ice cube trays is enough.

asalcedo wrote:
I need to add a couple of tees to a sealed central heating system.

It is a large one with more than 400 litres of water in it.

I am thinking of leaving some large radiators full of water by closing
both valves in each of them and drain the rest of the system. Then cut
the pipes and solder.

By leaving some radiators full of water I save time (shorter draining,
less venting etc.), water and inhibitor.

Can this be done or will I run the risk of unexpected water ruining the
soldering?

Do you have to solder? For grafting bits onto an existing system, I find
that a service valve (full bore) and a pushfit fitting of some sort
(cuprofit look almost as neat as capillary) will let you cut into a
"live" system and not lose more than a cup full of water. You can then
extend at your leisure and use the valves to finally bring the new bit
online.

--
Cheers,

John.

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

wrote:
On 2 Oct, 18:28, asalcedo wrote:
I need to add a couple of tees to a sealed central heating system.

It is a large one with more than 400 litres of water in it.

I am thinking of leaving some large radiators full of water by closing
both valves in each of them and drain the rest of the system. Then cut
the pipes and solder.

By leaving some radiators full of water I save time (shorter draining,
less venting etc.), water and inhibitor.

Can this be done or will I run the risk of unexpected water ruining the
soldering?

--
asalcedo

I did this a little while ago by freezing the pipes. I looked at the
kit you can buy from B&Q and when I had recovered from the shock of
seeing the price I had a think and wondered if you could do the same
thing with butane. I ended up buying a few tins of butane for 60p each
from a cheap shop and then wrapping the pipe in old socks, making a
pipe from a length of thin copper tube and injecting the butane into
the sock. I have a temperature probe, bought for cooking, and within a
minute or two the temperature was -15C. I know it is obvious, but I
suppose I ought to say it, if you try this makes sure it is well
ventilated and no naked flames etc. etc. It got so bloody cold that I
reckon it would have stayed frozen for a couple of hours, especially
if it was wrapped in silver foil.
is that wise if you are going to then solder the tee's???
I do hope you have some bloody good insurance

--
Kevin R
Reply address works

John Rumm wrote:
asalcedo wrote:
I need to add a couple of tees to a sealed central heating system.

It is a large one with more than 400 litres of water in it.

I am thinking of leaving some large radiators full of water by
closing both valves in each of them and drain the rest of the
system. Then cut the pipes and solder.

By leaving some radiators full of water I save time (shorter
draining, less venting etc.), water and inhibitor.

Can this be done or will I run the risk of unexpected water ruining
the soldering?

Do you have to solder? For grafting bits onto an existing system, I
find that a service valve (full bore) and a pushfit fitting of some
sort (cuprofit look almost as neat as capillary) will let you cut
into a "live" system and not lose more than a cup full of water. You
can then extend at your leisure and use the valves to finally bring
the new bit online.

By 'live' do you mean full of water under header tank pressure?


--
Dave - The Medway Handyman
www.medwayhandyman.co.uk

The Medway Handyman wrote:

Do you have to solder? For grafting bits onto an existing system, I
find that a service valve (full bore) and a pushfit fitting of some
sort (cuprofit look almost as neat as capillary) will let you cut
into a "live" system and not lose more than a cup full of water. You
can then extend at your leisure and use the valves to finally bring
the new bit online.

By 'live' do you mean full of water under header tank pressure?

Yup, or on a sealed system - just drain a little water from it to drop
the pressure before you start. (a couple of litres will normally be
enough).

My preferred technique is have the fitting and valve ready assembled,
and use a pipe cutter on the offending pipe (close to somewhere like a
rad valve so that there will only be water flow from one direction).
Once it starts to hiss, cut a bit further, and then give a sharp wiggle
to snap off the pipe, placing your thumb over the wet end as you do. Now
pick up the prepared fitting, and swap its position for your thumb.
Finally wipe your glasses to remove the splashes! ;-)

(Old towel under the work area of course!)

--
Cheers,

John.

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

"John Rumm" wrote in message
et...
The Medway Handyman wrote:

Do you have to solder? For grafting bits onto an existing system, I
find that a service valve (full bore) and a pushfit fitting of some
sort (cuprofit look almost as neat as capillary) will let you cut
into a "live" system and not lose more than a cup full of water. You
can then extend at your leisure and use the valves to finally bring
the new bit online.

By 'live' do you mean full of water under header tank pressure?

Yup, or on a sealed system - just drain a little water from it to drop the
pressure before you start. (a couple of litres will normally be enough).

My preferred technique is have the fitting and valve ready assembled, and
use a pipe cutter on the offending pipe (close to somewhere like a rad
valve so that there will only be water flow from one direction). Once it
starts to hiss, cut a bit further, and then give a sharp wiggle to snap
off the pipe, placing your thumb over the wet end as you do. Now pick up
the prepared fitting, and swap its position for your thumb. Finally wipe
your glasses to remove the splashes! ;-)

(Old towel under the work area of course!)


Pretty much exactly what I did when I last added to the central heating, as
it was under the (ground!) floor floorboards, spillage wasn't really an
issue (Other than the bit that always spurts up directly into your face, of
course!)

Toby...

"John Rumm" wrote in message
et...
The Medway Handyman wrote:

Do you have to solder? For grafting bits onto an existing system, I
find that a service valve (full bore) and a pushfit fitting of some
sort (cuprofit look almost as neat as capillary) will let you cut
into a "live" system and not lose more than a cup full of water. You
can then extend at your leisure and use the valves to finally bring
the new bit online.

By 'live' do you mean full of water under header tank pressure?

Yup, or on a sealed system - just drain a little water from it to drop
the pressure before you start. (a couple of litres will normally be
enough).

My preferred technique is have the fitting and valve ready assembled,
and use a pipe cutter on the offending pipe (close to somewhere like a
rad valve so that there will only be water flow from one direction).
Once it starts to hiss, cut a bit further, and then give a sharp wiggle
to snap off the pipe, placing your thumb over the wet end as you do. Now
pick up the prepared fitting, and swap its position for your thumb.
Finally wipe your glasses to remove the splashes! ;-)

(Old towel under the work area of course!)

--
Cheers,

John.

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

The only way to do it.

John Rumm wrote:
The Medway Handyman wrote:

Do you have to solder? For grafting bits onto an existing system, I
find that a service valve (full bore) and a pushfit fitting of some
sort (cuprofit look almost as neat as capillary) will let you cut
into a "live" system and not lose more than a cup full of water. You
can then extend at your leisure and use the valves to finally bring
the new bit online.

By 'live' do you mean full of water under header tank pressure?

Yup, or on a sealed system - just drain a little water from it to drop
the pressure before you start. (a couple of litres will normally be
enough).

My preferred technique is have the fitting and valve ready assembled,
and use a pipe cutter on the offending pipe (close to somewhere like a
rad valve so that there will only be water flow from one direction).
Once it starts to hiss, cut a bit further, and then give a sharp
wiggle to snap off the pipe, placing your thumb over the wet end as
you do. Now pick up the prepared fitting, and swap its position for
your thumb. Finally wipe your glasses to remove the splashes! ;-)

(Old towel under the work area of course!)


Who dares wins huh?

I'll bear that in mind...



--
Dave - The Medway Handyman
www.medwayhandyman.co.uk

The Medway Handyman wrote:
John Rumm wrote:
The Medway Handyman wrote:

Do you have to solder? For grafting bits onto an existing system, I
find that a service valve (full bore) and a pushfit fitting of some
sort (cuprofit look almost as neat as capillary) will let you cut
into a "live" system and not lose more than a cup full of water. You
can then extend at your leisure and use the valves to finally bring
the new bit online.
By 'live' do you mean full of water under header tank pressure?
Yup, or on a sealed system - just drain a little water from it to drop
the pressure before you start. (a couple of litres will normally be
enough).

My preferred technique is have the fitting and valve ready assembled,
and use a pipe cutter on the offending pipe (close to somewhere like a
rad valve so that there will only be water flow from one direction).
Once it starts to hiss, cut a bit further, and then give a sharp
wiggle to snap off the pipe, placing your thumb over the wet end as
you do. Now pick up the prepared fitting, and swap its position for
your thumb. Finally wipe your glasses to remove the splashes! ;-)

(Old towel under the work area of course!)


Who dares wins huh?

Sure - show it who is boss!

I'll bear that in mind...

Just don't do what a mate of mine did... needed to get a compression
service valve onto a rad feed and return pipes such that they could be
split to add a new rad. I had described the technique well enough I
thought - I was upstairs when I heard the yell. Came down to find one
rather wet looking chap standing next to a rad tail with service valve
attached, and a floor and ceiling covered with black gloop! He said,
"you can do the other side!". So, cut, wiggle, thumb, pre-assembled
valve on and held down to obstruct 85% of the flow, quick turn with a
spanner to halt the rest, before finally tightening into final position.
While watching he then said, "oh, I see - you put the whole valve on
in one go..."

Turns out that having cut the pipe, he then set about sliding over first
the backnut, then olive, then valve body, all the time doing the thumb
hokey-kokey before finally attempting to get them all together and doing
up the nut.

--
Cheers,

John.

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

John Rumm wrote:
The Medway Handyman wrote:
John Rumm wrote:
The Medway Handyman wrote:

Do you have to solder? For grafting bits onto an existing system,
I find that a service valve (full bore) and a pushfit fitting of
some sort (cuprofit look almost as neat as capillary) will let
you cut into a "live" system and not lose more than a cup full of
water. You can then extend at your leisure and use the valves to
finally bring the new bit online.
By 'live' do you mean full of water under header tank pressure?
Yup, or on a sealed system - just drain a little water from it to
drop the pressure before you start. (a couple of litres will
normally be enough).

My preferred technique is have the fitting and valve ready
assembled, and use a pipe cutter on the offending pipe (close to
somewhere like a rad valve so that there will only be water flow
from one direction). Once it starts to hiss, cut a bit further, and
then give a sharp wiggle to snap off the pipe, placing your thumb
over the wet end as you do. Now pick up the prepared fitting, and
swap its position for your thumb. Finally wipe your glasses to
remove the splashes! ;-) (Old towel under the work area of course!)


Who dares wins huh?

Sure - show it who is boss!

I'll bear that in mind...

Just don't do what a mate of mine did... needed to get a compression
service valve onto a rad feed and return pipes such that they could be
split to add a new rad. I had described the technique well enough I
thought - I was upstairs when I heard the yell. Came down to find one
rather wet looking chap standing next to a rad tail with service valve
attached, and a floor and ceiling covered with black gloop! He said,
"you can do the other side!". So, cut, wiggle, thumb, pre-assembled
valve on and held down to obstruct 85% of the flow, quick turn with a
spanner to halt the rest, before finally tightening into final
position. While watching he then said, "oh, I see - you put the
whole valve on in one go..."

Turns out that having cut the pipe, he then set about sliding over
first the backnut, then olive, then valve body, all the time doing
the thumb hokey-kokey before finally attempting to get them all
together and doing up the nut.


This sort of thing?

http://www.screwfix.com/prods/18814/...ng-Valve-15mm#

Presumably you need to pre clean the pipe?


--
Dave - The Medway Handyman
www.medwayhandyman.co.uk

On Thu, 2 Oct 2008 22:29:23 +0100, dennis@home wrote:

You can probably get cold enough by mixing salt and crushed ice..

That mixture will hold fairly close to 0C but will be pull heat from it's
surroundings whilst doing it. It might be able to freeze a pipe provided
you can ensuer that it is getting it's heat from the pipe and water rather
than the room in general. Certainly wouldn't be as quick as a proper pipe
freezer or the butane trick (that's for use in extremis only I think).

This simple maintenace of a a CH system has popped up several times
recently. Provided the system is sealed, as in a proper sealed system or a
open vented one with bungs in the feed and expansion pipes then as no air
can get in no water(*) can get out. Just remember to only have *one*
opening at any one time.

(*) Or only minimal like a mug full so still best to have some catching
equipment and old towels about.

--
Cheers
Dave.

On Fri, 03 Oct 2008 03:27:11 +0100, John Rumm wrote:

Just don't do what a mate of mine did... needed to get a compression
service valve onto a rad feed and return pipes such that they could be
split to add a new rad. I had described the technique well enough I
thought - I was upstairs when I heard the yell. Came down to find one
rather wet looking chap standing next to a rad tail with service valve
attached, and a floor and ceiling covered with black gloop! He said,
"you can do the other side!". So, cut, wiggle, thumb, pre-assembled
valve on and held down to obstruct 85% of the flow, quick turn with a
spanner to halt the rest, before finally tightening into final position.
While watching he then said, "oh, I see - you put the whole valve on
in one go..."

Turns out that having cut the pipe, he then set about sliding over first
the backnut, then olive, then valve body, all the time doing the thumb
hokey-kokey before finally attempting to get them all together and doing
up the nut.

ROFL, that needs to go in the FAQ next to Expanding Foam. B-)

--
Cheers
Dave.

Dave Liquorice wrote:
On Thu, 2 Oct 2008 22:29:23 +0100, dennis@home wrote:

You can probably get cold enough by mixing salt and crushed ice..

That mixture will hold fairly close to 0C but will be pull heat from it's
surroundings whilst doing it. It might be able to freeze a pipe provided
you can ensuer that it is getting it's heat from the pipe and water rather
than the room in general. Certainly wouldn't be as quick as a proper pipe
freezer or the butane trick (that's for use in extremis only I think).

This simple maintenace of a a CH system has popped up several times
recently. Provided the system is sealed, as in a proper sealed system or a
open vented one with bungs in the feed and expansion pipes then as no air
can get in no water(*) can get out. Just remember to only have *one*
opening at any one time.


And that includes NOT flushing a loo halfway through the job, and having
the cisten ballcock open and let half a tank of scalding hot water over
your wife, who is still upstairs in the other bathroom you left to have
a pee..

(*) Or only minimal like a mug full so still best to have some catching
equipment and old towels about.

The Medway Handyman wrote:

Turns out that having cut the pipe, he then set about sliding over
first the backnut, then olive, then valve body, all the time doing
the thumb hokey-kokey before finally attempting to get them all
together and doing up the nut.


This sort of thing?

http://www.screwfix.com/prods/18814/...ng-Valve-15mm#

Yup, or just an ordinary compression valve, a short stub of pipe and a
straight connector.

Presumably you need to pre clean the pipe?

Depends on the state of the pipe really. Pushfit does not usually care
about it being bright and shiny in the way solder does.


--
Cheers,

John.

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

"Dave Liquorice" wrote in message
ll.net...
On Thu, 2 Oct 2008 22:29:23 +0100, dennis@home wrote:

You can probably get cold enough by mixing salt and crushed ice..

That mixture will hold fairly close to 0C

I suggest you try it.. It can get down to -8C with ease.

but will be pull heat from it's
surroundings whilst doing it. It might be able to freeze a pipe provided
you can ensuer that it is getting it's heat from the pipe and water rather
than the room in general. Certainly wouldn't be as quick as a proper pipe
freezer or the butane trick (that's for use in extremis only I think).

Pipe freezers also get heat from the surroundings, you need an insulated
container of some sort, e.g. tape a bag around the pipe and wrap it in cloth
to insulate it.

"The Natural Philosopher" wrote in message
...
Dave Liquorice wrote:
On Thu, 2 Oct 2008 22:29:23 +0100, dennis@home wrote:

You can probably get cold enough by mixing salt and crushed ice..

That mixture will hold fairly close to 0C but will be pull heat from it's
surroundings whilst doing it. It might be able to freeze a pipe provided
you can ensuer that it is getting it's heat from the pipe and water
rather than the room in general. Certainly wouldn't be as quick as a
proper pipe freezer or the butane trick (that's for use in extremis only
I think).

This simple maintenace of a a CH system has popped up several times
recently. Provided the system is sealed, as in a proper sealed system or
a open vented one with bungs in the feed and expansion pipes then as no
air can get in no water(*) can get out. Just remember to only have *one*
opening at any one time.


And that includes NOT flushing a loo halfway through the job, and having
the cisten ballcock open and let half a tank of scalding hot water over
your wife, who is still upstairs in the other bathroom you left to have a
pee..

One of the advantages of mains pressure hot water such as combis.

On Fri, 03 Oct 2008 10:49:47 +0100, The Natural Philosopher wrote:

Provided the system is sealed, as in a proper sealed system or a open
vented one with bungs in the feed and expansion pipes then as no air
can get in no water(*) can get out. Just remember to only have *one*
opening at any one time.

And that includes NOT flushing a loo halfway through the job, and having
the cisten ballcock open and let half a tank of scalding hot water over
your wife, who is still upstairs in the other bathroom you left to have
a pee..

I don't get this. The CH circulating water system is totaly isolated from
the distribution of potable water to the places that use it. Surely this
is even the case with these new fangled pressurised combi systems that I
really know naff all about.

--
Cheers
Dave.

Well, in the end I was right.

I closed both valves in most of the large radiators and let a few small ones in different floors drain.

I selected a point to cut the pipe slightly higher than the drain cock.

Sure, there was water coming out of the drain cock in spurs, at random intervals, but it had no pressure.

The pipe was dry at the point of the cut, which allowed me to solder without a hitch.

When I reopened the radiator valves the system had still about 1 bar of pressure, without adding any new water. Needless to say that this saved a lot of time and inhibitor.

Pipe freezing , or using push-fit valve fittings, is something that I am well aware of (I have a pipe freezing kit) but I did want to use capillary because the tees are going to be put under a lot of stress and it give me more piece of mind. Being a 22mm pipe, and wanting to solder, made pipe freezing out of the question.