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[Misc] Draining house radiator for decorating



Worthing exile

New member
May 12, 2009
1,219
Last night I went to drain my kitchen radiator and remove it to prepare for decorating.
Left hand side is the side with numbers so following advice, turned it anti-clockwise to 0.
Right hand side has the conventional take plastic top off and use pliers to turn clockwise to shut it off.
Used grips on the big nut to drain water.
After about 15 minutes it was obvious that water is still entering the radiator which must be from the left hand side.

How do I shut off the water to both sides without turning the whole system off?

It all use to be so easy.:mad:
 






Stat Brother

Well-known member
NSC Patron
Jul 11, 2003
73,888
West west west Sussex
WTF

f8b059db8e134568e1b75913f44ad1dc--radiators-painting.jpg


Job done.
 


pishrat

New member
Feb 27, 2008
17
Last night I went to drain my kitchen radiator and remove it to prepare for decorating.
Left hand side is the side with numbers so following advice, turned it anti-clockwise to 0.
Right hand side has the conventional take plastic top off and use pliers to turn clockwise to shut it off.
Used grips on the big nut to drain water.
After about 15 minutes it was obvious that water is still entering the radiator which must be from the left hand side.

How do I shut off the water to both sides without turning the whole system off?

It all use to be so easy.:mad:

You don't need to shut off both sides as one is flow, the other is return. when turning the TRV valve off you should have no water unless the heating is running. Either the system is running or the valve isn't shutting properly.
 


Worthing exile

New member
May 12, 2009
1,219
You don't need to shut off both sides as one is flow, the other is return. when turning the TRV valve off you should have no water unless the heating is running. Either the system is running or the valve isn't shutting properly.

Thanks for this. So as long as the left side is at zero and the system is off, that should be fine.
 




Bold Seagull

strong and stable with me, or...
Mar 18, 2010
30,465
Hove
Thanks for this. So as long as the left side is at zero and the system is off, that should be fine.

Unless the TRV isn't working. And always ensure both are closed. Trying unscrewing the plastic body of the TRV which should just come off, and check the pin which the TRV operates is able to be pressed and depressed without being stuck. It will look like this:
Myson-TRV-body.png
 
Last edited:


Worthing exile

New member
May 12, 2009
1,219
Unless the TRV isn't working. Trying unscrewing the plastic body of the TRV which should just come off, and check the pin which the TRV operates is able to be pressed and depressed without being stuck. It will look like this:
Myson-TRV-body.png

Yes I took the top off last night. Will try pressing it tonight. Mine was black ha ha.
 


Arthritic Toe

Well-known member
Nov 25, 2005
2,488
Swindon
Unless the TRV isn't working. Trying unscrewing the plastic body of the TRV which should just come off, and check the pin which the TRV operates is able to be pressed and depressed without being stuck. It will look like this:

If the TRV is knackered you can usually take off the plastic body as above, shove a 5p coin in it and then screw it back on (i.e. to hold the pin down).
 




Uncle C

Well-known member
Jul 6, 2004
11,711
Bishops Stortford
You don't need to shut off both sides as one is flow, the other is return. when turning the TRV valve off you should have no water unless the heating is running. Either the system is running or the valve isn't shutting properly.

Even if the system isn't running it still has water pressure in it, so you need to turn off both taps, not just one.
 


pishrat

New member
Feb 27, 2008
17
Even if the system isn't running it still has water pressure in it, so you need to turn off both taps, not just one.

the return doesn't move if it isn't connected to the flow. you can cut the return pipe and the water will just sit.
 


pishrat

New member
Feb 27, 2008
17
the heating system is a closed loop. the flow is made by a pump. If you are turning the valve off and you still have flow you might as well just snatch the pipe and cap it off and get a new TRV. For what you are trying to achieve just close/cap the flow. undo the nut and drain the rad. Using a builders rubble bag works well for this.

When the rad has drained you can undo the return nut. you will get a few drops of water from the copper tail if the pipe isn't level and the water will sit in the pipe. no need for capping. then you can remove the rad. job done.
 




Skuller

Well-known member
NSC Patron
Jun 3, 2017
340
Be careful leaving a radiator disconnected when the temperature falls. "Zero" on the thermostat doesn't always mean "shut-off". It can mean "shut off until the temperature drops really low". I removed a radiator in a December and then left an empty unheated house I was renovating intending to replace it in a few days' time. When I returned, the thermostatic valve had opened when we had sub-zero temperatures and flooded the house.
 


Bodian

Well-known member
May 3, 2012
14,280
Cumbria
In my experience it will leak, whatever you do! I hate plumbing - I always end up with smashed knuckles because bits are hidden round the back of stuff, it never seems to work quite right, and I end up cursing a lot.
 


BN9 BHA

DOCKERS
NSC Patron
Jul 14, 2013
22,693
Newhaven
You don't need to shut off both sides as one is flow, the other is return. when turning the TRV valve off you should have no water unless the heating is running. Either the system is running or the valve isn't shutting properly.

Wrong :facepalm:

WARNING - Under no circumstances take this advice
 




BN9 BHA

DOCKERS
NSC Patron
Jul 14, 2013
22,693
Newhaven
Unless the TRV isn't working. And always ensure both are closed. Trying unscrewing the plastic body of the TRV which should just come off, and check the pin which the TRV operates is able to be pressed and depressed without being stuck. It will look like this:
Myson-TRV-body.png

Good and correct advice :thumbsup:
 




BN9 BHA

DOCKERS
NSC Patron
Jul 14, 2013
22,693
Newhaven
Presumably because gravity will create it's own pressure in the loop?

I have been a plumber for many years, I often take off rads when a room needs plastering, decorating or installing a new rad, I always ensure both rad valves are closed and water removed from the rad before removing ( the rad )
 


Blue3

Well-known member
Jan 27, 2014
5,836
Lancing
Last night I went to drain my kitchen radiator and remove it to prepare for decorating.
Left hand side is the side with numbers so following advice, turned it anti-clockwise to 0.
Right hand side has the conventional take plastic top off and use pliers to turn clockwise to shut it off.
Used grips on the big nut to drain water.
After about 15 minutes it was obvious that water is still entering the radiator which must be from the left hand side.

How do I shut off the water to both sides without turning the whole system off?

It all use to be so easy.:mad:

You will probably find a bit of play on the pipe work if you have just Loosen the nuts on either side of the radiator it will leak a little now quickly lift and lay the radiator flat tighten on the floor the nuts
 




BN9 BHA

DOCKERS
NSC Patron
Jul 14, 2013
22,693
Newhaven
Be careful leaving a radiator disconnected when the temperature falls. "Zero" on the thermostat doesn't always mean "shut-off". It can mean "shut off until the temperature drops really low". I removed a radiator in a December and then left an empty unheated house I was renovating intending to replace it in a few days' time. When I returned, the thermostatic valve had opened when we had sub-zero temperatures and flooded the house.

Also very good advice this.
I always cap off the outlet side of a TRV if the radiator is removed.
 




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