I need some advice on the best way to drain down my CH system to add
an additional radiator. I'm in a first floor flat and the pipes run
under the wooden floor. There is a drain cock on one of the radiators
but correct me if I'm wrong this will only drain to the level of the
drain cock? All the pipes under the floor will still be full of water.

My thoughts were to buy one of those self piercing taps that you can
use for washing machines etc which you can fix without having to empty
the pipe of water. I could fix this under the floor and then attach a
length of hose to this. The hose will of course travel uphill for a
short length as it passes up to floor level from under the floor.
Could I syphon the remaining water out ?

Any other ideas bearing in mind my requirement of not wanting to make
a mess of downstairs ceiling!

On 25 Jan 2005 04:06:02 -0800, (Andy Hide)
wrote:

I need some advice on the best way to drain down my CH system to add
an additional radiator. I'm in a first floor flat and the pipes run
under the wooden floor. There is a drain cock on one of the radiators
but correct me if I'm wrong this will only drain to the level of the
drain cock? All the pipes under the floor will still be full of water.

Does it matter if the pipes under the floor are full or water?

If the water is drained below the level of the radiator, there won't
be any spillage when you disconnect it.

A big car sponge is useful for catching drips!

Markus

"Markus Splenius" wrote in message
...
On 25 Jan 2005 04:06:02 -0800, (Andy Hide)
wrote:

I need some advice on the best way to drain down my CH system to add
an additional radiator. I'm in a first floor flat and the pipes run
under the wooden floor. There is a drain cock on one of the radiators
but correct me if I'm wrong this will only drain to the level of the
drain cock? All the pipes under the floor will still be full of water.

Does it matter if the pipes under the floor are full or water?

If the water is drained below the level of the radiator, there won't
be any spillage when you disconnect it.

A big car sponge is useful for catching drips!

Markus

"Andy Hide" wrote in message
om...
I need some advice on the best way to drain down my CH system to add
an additional radiator. I'm in a first floor flat and the pipes run
under the wooden floor. There is a drain cock on one of the radiators
but correct me if I'm wrong this will only drain to the level of the
drain cock? All the pipes under the floor will still be full of water.

My thoughts were to buy one of those self piercing taps that you can
use for washing machines etc which you can fix without having to empty
the pipe of water. I could fix this under the floor and then attach a
length of hose to this. The hose will of course travel uphill for a
short length as it passes up to floor level from under the floor.
Could I syphon the remaining water out ?

Any other ideas bearing in mind my requirement of not wanting to make
a mess of downstairs ceiling!

Sorry about the blank response - pressed the wrong key before typing!
Depending upon how you want to do the job you could always use a pipe
freezer kit to avoid draining at all. I've fitted a number of TRV's on my
radiators using freezer kits. The ice plug lasts for 30 - 40 minutes which
is usually plenty of time to cut the pipe and fit a valve.

Kev

`On Tue, 25 Jan 2005 12:41:48 +0000, Markus Splenius wrote:

On 25 Jan 2005 04:06:02 -0800, (Andy Hide)
wrote:

I need some advice on the best way to drain down my CH system to add
an additional radiator. I'm in a first floor flat and the pipes run
under the wooden floor. There is a drain cock on one of the radiators
but correct me if I'm wrong this will only drain to the level of the
drain cock? All the pipes under the floor will still be full of water.

Does it matter if the pipes under the floor are full or water?

Only if you need to tee into them for the new rad, or solder close to the drain-down level.

In an earlier contribution to this discussion,
Markus Splenius wrote:

On 25 Jan 2005 04:06:02 -0800, (Andy Hide)
wrote:

I need some advice on the best way to drain down my CH system to add
an additional radiator. I'm in a first floor flat and the pipes run
under the wooden floor. There is a drain cock on one of the radiators
but correct me if I'm wrong this will only drain to the level of the
drain cock? All the pipes under the floor will still be full of
water.

Does it matter if the pipes under the floor are full or water?

Er, yes!

If the water is drained below the level of the radiator, there won't
be any spillage when you disconnect it.


True, BUT the OP wants to add an additional radiator. This will normally
require extra branches off the low level flow and return pipes. Breaking
into these will cause a flood if they are still full of water.

Question to the OP: Are the pipes under the floor all joined by soldered
joints, or are there any compression joints? If there's a compression joint
you can get at, this is what I would do:
Firstly fully turn off both valves on all radiators to keep them full of
water - making a note of the open/closed position of each lockshield, so
that you can restore the balance.
Secondly, if it's a vented system, put bungs in the fill and vent pipes to
keep the water in the F&E tank
Thirdly, drain as much of the remaining water as you can, using the drain
cock which you mentioned.
Finally, crack a compression joint under the floor, with a shallow vessel**
under it to catch the remaining water.

** Foil take-away food dishes are ideal for this. You will either need 2,
and empty one into a bucket while the other is filling, or you will need to
do the joint up lightly each time you remove the dish to empty it. Also use
old towels under the dish to absorb any slight spills.
--
Cheers,
Set Square
______
Please reply to newsgroup. Reply address is invalid.

"Andy Hide" wrote in message
om...
I need some advice on the best way to drain down my CH system to add
an additional radiator. I'm in a first floor flat and the pipes run
under the wooden floor. There is a drain cock on one of the radiators
but correct me if I'm wrong this will only drain to the level of the
drain cock? All the pipes under the floor will still be full of water.

My thoughts were to buy one of those self piercing taps that you can
use for washing machines etc which you can fix without having to empty
the pipe of water. I could fix this under the floor and then attach a
length of hose to this. The hose will of course travel uphill for a
short length as it passes up to floor level from under the floor.
Could I syphon the remaining water out ?

Any other ideas bearing in mind my requirement of not wanting to make
a mess of downstairs ceiling!
Someone recently suggested using a WET vac type "Hoover" to deal with this
situation, the method being (if I remember correctly), remove rad and drain
tap, seal the suction hose on to the pipe with a bit of PVC tape or
similar, open up the other rads to let air in and then switch it on, sucking
the water into the wet vac reservoir. I've never tried it but it seems like
a good idea. if you have the means or inclination to try it, please let us
know if it works.
Cheers
Tom

My thoughts were to buy one of those self piercing taps that you can
use for washing machines etc which you can fix without having to empty
the pipe of water. I could fix this under the floor and then attach a
length of hose to this. The hose will of course travel uphill for a
short length as it passes up to floor level from under the floor.
Could I syphon the remaining water out ?

I don't see why not. Put it in an accessible location with a valve, so you
can drain it next time. Obviously, ensure that the free end of the hose is
well below the underfloor pipe level and ensure you don't drain using the
conventional drain first, or you'll never charge the syphon. The water in
the system must be above the level of the highest part of the hose loop.

Christian.

On Tue, 25 Jan 2005 14:44:18 -0000, "Set Square"
wrote:

In an earlier contribution to this discussion,
Markus Splenius wrote:

If the water is drained below the level of the radiator, there won't
be any spillage when you disconnect it.


True, BUT the OP wants to add an additional radiator. This will normally
require extra branches off the low level flow and return pipes. Breaking
into these will cause a flood if they are still full of water.

Doh! Yes. I didn't read.

M.

Andy Hide wrote:
I need some advice on the best way to drain down my CH system to add
an additional radiator. I'm in a first floor flat and the pipes run
under the wooden floor. There is a drain cock on one of the radiators
but correct me if I'm wrong this will only drain to the level of the
drain cock? All the pipes under the floor will still be full of water.

My thoughts were to buy one of those self piercing taps that you can
use for washing machines etc which you can fix without having to empty
the pipe of water. I could fix this under the floor and then attach a
length of hose to this. The hose will of course travel uphill for a
short length as it passes up to floor level from under the floor.
Could I syphon the remaining water out ?

Any other ideas bearing in mind my requirement of not wanting to make
a mess of downstairs ceiling!
Why would anyone install a central heating system without putting in
proper provision to drain it? It seems senseless to me. Are you 100%
sure that no other 'main' draincock exists outside?

Why would anyone install a central heating system without putting in
proper provision to drain it? It seems senseless to me. Are you 100%
sure that no other 'main' draincock exists outside?

It is quite common for the pipework below floor level not to have any
drainage ability. The same situation existings on my system and almost every
system I've worked on. The main difference between those cases is this is
that the pipework for me is below a suspended ground floor. It matters
little if you just cut the pipe and have the bottom dregs pour away, unlike
a flat with more accommodation below.

Christian.

In article , Cuprager wrote:
Why would anyone install a central heating system without
putting in proper provision to drain it?

Because if they're not going to flush it through once it's installed
what's the point? Can't you spell cowboy? g

--
Tony Bryer SDA UK 'Software to build on' http://www.sda.co.uk
Free SEDBUK boiler database browser http://www.sda.co.uk/qsedbuk.htm

Tom wrote:
please let us
know if it works.

Yes, it works perfectly.

Regards
Capitol