Hi

I need to replace one radiator and also replace the valves on another. Ive
never done drained the system before so I thought I would ask the experts.

My main confusion is whether there is valve that I can open on the Vaillant
VCW GB240H combi boiler (at least that is one of the three model numbers on
the instructions).

I have put a picture of the pipework at
http://www.atbn38.dsl.pipex.com/boiler.jpg

I have workred out the following. There is a braided pipe that goes from 1
to 2 with a valve at each end. If I open both these ( as I have done in the
past) then water is added to the system. The pipe at 2 is hot so is
therefore the heating circuit whereas pipe at 1 is the cold water supply. I
therefore assume that 3 is where the cold water supply supplies the hot
water system.

The valve at 4 has some kind of locking mechanism on hte right hand side and
has a connection to the overflow pipe. Is there something here I can use to
drain the system ? Do I turn of the mains to hte boiler first ?


To re-fill the system, do I simply start refilling the system ? Should the
boiler be on so I can feel the hot water in the radiators ? I guess I need
to open the bleed valves ? Shall I do this on one radiator at a time ?

I tried searching for a step by step guide but failed miserably. Can anyone
help ?

Thanks

Tim

On Fri, 11 Mar 2005 06:51:52 +0000, Tim Smith wrote:

See FAQ on SealedCH for a bit of background.

Identification:

1) The filling loop entry valve.
2) The connection of the filling loop to the primary return from the
radiators.
3) A back nut on the mains cold water inlet connection to the
boiler.
4) The pressure relief valve.

The slick way to drain your radiators is. Turn boiler to HW only.
Turn the valve which is about 3cm to the 'south east' of (3) so that's
its slot is horizontal. Do the same with the similar valve about 20cm to
the left on the primary flow pipe.

The boiler can still be used for HW. You can work on the radiators as
needed. You can remove the water through a drain cock somewhere
(ideally it is situated outside) it will look like screwfix part #11421.
Expect the washer of that drain cock to be totally knackered.

Since you are replacing a radiator and that will likely mean replacing
both valves, totally draining the radiators is advised. However with
care you could be able to work on one valve at a time without draining
down the unaffected radiators.

If the boiler pressure gauge falls when you begin draining then turn the
boiler off.

Before refilling turn the boiler off and open the isolating valves back to
slots vertical. When refilling care should be taken to expel as much air
as possible (the boiler has an auto air vent but it could easily be
defective or its dust cap closed). I recommend turning the gas isolator
off (it's just above the metal bracket joining all the pipes and its on
the middle pipe of the three small pipes) it operates with 1/4 turn, this
will allow the pump to get the air out of the heat exchanger safely before
the first firing. I'm being a bit cautious here but I don't know your
level of experience.

HTH



Hi

I need to replace one radiator and also replace the valves on another. Ive
never done drained the system before so I thought I would ask the experts.

My main confusion is whether there is valve that I can open on the Vaillant
VCW GB240H combi boiler (at least that is one of the three model numbers on
the instructions).

I have put a picture of the pipework at
http://www.atbn38.dsl.pipex.com/boiler.jpg

I have workred out the following. There is a braided pipe that goes from 1
to 2 with a valve at each end. If I open both these ( as I have done in the
past) then water is added to the system. The pipe at 2 is hot so is
therefore the heating circuit whereas pipe at 1 is the cold water supply. I
therefore assume that 3 is where the cold water supply supplies the hot
water system.

The valve at 4 has some kind of locking mechanism on hte right hand side and
has a connection to the overflow pipe. Is there something here I can use to
drain the system ? Do I turn of the mains to hte boiler first ?


To re-fill the system, do I simply start refilling the system ? Should the
boiler be on so I can feel the hot water in the radiators ? I guess I need
to open the bleed valves ? Shall I do this on one radiator at a time ?

I tried searching for a step by step guide but failed miserably. Can anyone
help ?

Thanks

Tim
--
Ed Sirett - Property maintainer and registered gas fitter.
The FAQ for uk.diy is at http://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

Hi Ed

Thanks for the reply. I did actaully do the work I needed today before I saw
your reply. Everything seems to be OK but here's what I did.

1. Shut down valves of radiator to be temporarily removed and removed
radiator after draining through bleed valve.
2. Turned boiler to permanently off on timeswitch.
3. The system doesnt have a drain cock, so I drained the heating system
through the valve of the radiator that I had removed - only got a bucket or
two.
4. Got shouted at by wife as hot water didnt work !
5. Replaced valves on radiator.
6. Pressurised using filler loop upto 1 bar (where the red mark is).
7. Cross fingers, turned on boiler and monitored for leaks and also pressure
drops.
8. Pressure rose but only within normal limits and still appears to be fine.

So, now fitting this in with what you said.

1. I did try to shut off the two valves you mention that arent numbers but
at least 1 of them didnt want to turn at all - so I left them.
2. I didnt turn off the gas valve (again because I hadnt seen your post).

I still need to go round bleeding the radiators and (I guess) filling the
water up a bit again.

I assume that everything I did, despite it not being exactly as per your
instrucitons, is OK and that Ive not left anything in a dangerous state. My
level of experience is none when it comes to boilers but I like to learn and
have a modicum of intelligence.

Question though, given that in a combi the ho****er and heating are
separate, why didnt the hot water work when I drained the system of water. I
surmise the following - both systems hot water and heating pass over the
same flame. The boiler realises that there is no water in the heating
becuase I drained the boiler as well (since I didnt shut off the two valves)
and refuses to fire up. Is this correct ? Therefore if I had shut off the
two valves, the boiler would still have had water in it and fired up....

Is this all correct ?

Thanks for the help

Tim


"Ed Sirett" wrote in message
news
On Fri, 11 Mar 2005 06:51:52 +0000, Tim Smith wrote:

See FAQ on SealedCH for a bit of background.

Identification:

1) The filling loop entry valve.
2) The connection of the filling loop to the primary return from the
radiators.
3) A back nut on the mains cold water inlet connection to the
boiler.
4) The pressure relief valve.

The slick way to drain your radiators is. Turn boiler to HW only.
Turn the valve which is about 3cm to the 'south east' of (3) so that's
its slot is horizontal. Do the same with the similar valve about 20cm to
the left on the primary flow pipe.

The boiler can still be used for HW. You can work on the radiators as
needed. You can remove the water through a drain cock somewhere
(ideally it is situated outside) it will look like screwfix part #11421.
Expect the washer of that drain cock to be totally knackered.

Since you are replacing a radiator and that will likely mean replacing
both valves, totally draining the radiators is advised. However with
care you could be able to work on one valve at a time without draining
down the unaffected radiators.

If the boiler pressure gauge falls when you begin draining then turn the
boiler off.

Before refilling turn the boiler off and open the isolating valves back to
slots vertical. When refilling care should be taken to expel as much air
as possible (the boiler has an auto air vent but it could easily be
defective or its dust cap closed). I recommend turning the gas isolator
off (it's just above the metal bracket joining all the pipes and its on
the middle pipe of the three small pipes) it operates with 1/4 turn, this
will allow the pump to get the air out of the heat exchanger safely before
the first firing. I'm being a bit cautious here but I don't know your
level of experience.

HTH



Hi

I need to replace one radiator and also replace the valves on another.
Ive
never done drained the system before so I thought I would ask the
experts.

My main confusion is whether there is valve that I can open on the
Vaillant
VCW GB240H combi boiler (at least that is one of the three model numbers
on
the instructions).

I have put a picture of the pipework at
http://www.atbn38.dsl.pipex.com/boiler.jpg

I have workred out the following. There is a braided pipe that goes from
1
to 2 with a valve at each end. If I open both these ( as I have done in
the
past) then water is added to the system. The pipe at 2 is hot so is
therefore the heating circuit whereas pipe at 1 is the cold water
supply. I
therefore assume that 3 is where the cold water supply supplies the hot
water system.

The valve at 4 has some kind of locking mechanism on hte right hand side
and
has a connection to the overflow pipe. Is there something here I can use
to
drain the system ? Do I turn of the mains to hte boiler first ?


To re-fill the system, do I simply start refilling the system ? Should
the
boiler be on so I can feel the hot water in the radiators ? I guess I
need
to open the bleed valves ? Shall I do this on one radiator at a time ?

I tried searching for a step by step guide but failed miserably. Can
anyone
help ?

Thanks

Tim
--
Ed Sirett - Property maintainer and registered gas fitter.
The FAQ for uk.diy is at http://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

Oh yes...and should I be adding some inhibitor or something now.

Does this have to be done at a particular location in the circuit ?

Tim


"Tim Smith" wrote in message
...
Hi Ed

Thanks for the reply. I did actaully do the work I needed today before I
saw
your reply. Everything seems to be OK but here's what I did.

1. Shut down valves of radiator to be temporarily removed and removed
radiator after draining through bleed valve.
2. Turned boiler to permanently off on timeswitch.
3. The system doesnt have a drain cock, so I drained the heating system
through the valve of the radiator that I had removed - only got a bucket
or
two.
4. Got shouted at by wife as hot water didnt work !
5. Replaced valves on radiator.
6. Pressurised using filler loop upto 1 bar (where the red mark is).
7. Cross fingers, turned on boiler and monitored for leaks and also
pressure
drops.
8. Pressure rose but only within normal limits and still appears to be
fine.

So, now fitting this in with what you said.

1. I did try to shut off the two valves you mention that arent numbers but
at least 1 of them didnt want to turn at all - so I left them.
2. I didnt turn off the gas valve (again because I hadnt seen your post).

I still need to go round bleeding the radiators and (I guess) filling the
water up a bit again.

I assume that everything I did, despite it not being exactly as per your
instrucitons, is OK and that Ive not left anything in a dangerous state.
My
level of experience is none when it comes to boilers but I like to learn
and
have a modicum of intelligence.

Question though, given that in a combi the ho****er and heating are
separate, why didnt the hot water work when I drained the system of water.
I
surmise the following - both systems hot water and heating pass over the
same flame. The boiler realises that there is no water in the heating
becuase I drained the boiler as well (since I didnt shut off the two
valves)
and refuses to fire up. Is this correct ? Therefore if I had shut off the
two valves, the boiler would still have had water in it and fired up....

Is this all correct ?

Thanks for the help

Tim


"Ed Sirett" wrote in message
news
On Fri, 11 Mar 2005 06:51:52 +0000, Tim Smith wrote:

See FAQ on SealedCH for a bit of background.

Identification:

1) The filling loop entry valve.
2) The connection of the filling loop to the primary return from the
radiators.
3) A back nut on the mains cold water inlet connection to the
boiler.
4) The pressure relief valve.

The slick way to drain your radiators is. Turn boiler to HW only.
Turn the valve which is about 3cm to the 'south east' of (3) so that's
its slot is horizontal. Do the same with the similar valve about 20cm to
the left on the primary flow pipe.

The boiler can still be used for HW. You can work on the radiators as
needed. You can remove the water through a drain cock somewhere
(ideally it is situated outside) it will look like screwfix part #11421.
Expect the washer of that drain cock to be totally knackered.

Since you are replacing a radiator and that will likely mean replacing
both valves, totally draining the radiators is advised. However with
care you could be able to work on one valve at a time without draining
down the unaffected radiators.

If the boiler pressure gauge falls when you begin draining then turn the
boiler off.

Before refilling turn the boiler off and open the isolating valves back
to
slots vertical. When refilling care should be taken to expel as much air
as possible (the boiler has an auto air vent but it could easily be
defective or its dust cap closed). I recommend turning the gas isolator
off (it's just above the metal bracket joining all the pipes and its on
the middle pipe of the three small pipes) it operates with 1/4 turn,
this
will allow the pump to get the air out of the heat exchanger safely
before
the first firing. I'm being a bit cautious here but I don't know your
level of experience.

HTH



Hi

I need to replace one radiator and also replace the valves on another.
Ive
never done drained the system before so I thought I would ask the
experts.

My main confusion is whether there is valve that I can open on the
Vaillant
VCW GB240H combi boiler (at least that is one of the three model
numbers
on
the instructions).

I have put a picture of the pipework at
http://www.atbn38.dsl.pipex.com/boiler.jpg

I have workred out the following. There is a braided pipe that goes
from
1
to 2 with a valve at each end. If I open both these ( as I have done
in
the
past) then water is added to the system. The pipe at 2 is hot so is
therefore the heating circuit whereas pipe at 1 is the cold water
supply. I
therefore assume that 3 is where the cold water supply supplies the
hot
water system.

The valve at 4 has some kind of locking mechanism on hte right hand
side
and
has a connection to the overflow pipe. Is there something here I can
use
to
drain the system ? Do I turn of the mains to hte boiler first ?


To re-fill the system, do I simply start refilling the system ? Should
the
boiler be on so I can feel the hot water in the radiators ? I guess I
need
to open the bleed valves ? Shall I do this on one radiator at a time ?

I tried searching for a step by step guide but failed miserably. Can
anyone
help ?

Thanks

Tim
--
Ed Sirett - Property maintainer and registered gas fitter.
The FAQ for uk.diy is at http://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

On Sat, 12 Mar 2005 18:41:34 +0000, Tim Smith wrote:



1. I did try to shut off the two valves you mention that arent numbers but
at least 1 of them didnt want to turn at all - so I left them.

It would probably have moved with enough oomph and the right tool, it
hasn't moved probably since the boiler was installed and that was probably
in excess of 10 years ago.


2. I didnt turn off the gas valve (again because I hadnt seen your post).

I was being very cautious. I think you were safer than I made out because
the boiler did not get drained and so little air got in
it. In the worst case where there is too much air the pump ceases to work.
However in this model that would be sufficient to stop the boiler working.


I still need to go round bleeding the radiators and (I guess) filling the
water up a bit again.

Yep, but you might as well add inhibitor first.


Question though, given that in a combi the ho****er and heating are
separate, why didnt the hot water work when I drained the system of water. I
surmise the following - both systems hot water and heating pass over the
same flame. The boiler realises that there is no water in the heating
becuase I drained the boiler as well (since I didnt shut off the two valves)
and refuses to fire up. Is this correct ? Therefore if I had shut off the
two valves, the boiler would still have had water in it and fired up....

In nearly all models the gas heats the primary water and that heats the
domestic HW in a secondary heat exchanger. No primary water means no
heating or HW.

You can add inhibitor any place thats convenient. I usually add it at the
non-bleed end of a convenient rad and let the displaced air out through
the bleed point. You need to have the rad at least partially drained
before adding. See the SealedCH FAQ


HTH