removing a rad and re-sitting - do i have to drain the sys?

[enigmatic]

i want to extend the pipework of the radiator in a bedroom so as its sitting into the wall which i've chased out, in order to take the rad off do i have to shut the whole system down and drain it or can i just isolate the one rad and do it that way?

i have a conventional boiler with cold water and expansion tank in the loft.

cheers

 

[swidders]

You don't need to drain the system just to take the rad off. However, if you're going to change pipework you will need to at least partially drain it so upstairs is empty.

You can isolate the rads by turning their valves off and drain the pipework - the only problems of doing it this way are that when you come to refill, you may get the occasional airlock, and the system will need rebalancing.

 

[enigmatic]

is this the fitting where i can turn the rad off to isolate it?

Untitled

• enigmatic
• 9 Feb 2009
• 1

also this is the trv type yeah?

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• enigmatic
• 9 Feb 2009
• 1

thanks very much

 

[Goldspoon]

Yes and yes.

 

[enigmatic]

ok thanks for that i'll try not to keep you here too long

once i've turned the valve i can start bleeding the rad then take it off and drain it or can i just take it off without bleeding it?

also if i wanted a partial shut down just to isolate upstairs what would i need to do?

its a conventional type system with a expansasion tank in the loft and boiler below that in a cupboad.

the joys of diy

 

[MANDATE]

When you have closed both valves of the radiator will still have water in it.

Opening the bleed nipple at top of radiator will do nothing. (at this stage)
You have to drain the radiator. If it does not have a drain off valve, then you have loosen the compression nut and catch the water in suitable container.
If the bleed nipple is closed and air cant enter at the top it restricts the flow, but opening it will allow you to control the flow.
You may also find the closed valves may leak a touch and it would be wise to fit blanking caps

 

[Goldspoon]

its a conventional type system with a expansasion tank in the loft and boiler below that in a cupboad.

the joys of diy

Stop new water entering by tying up the ball cock in the loft (smallest tank of two). Or you can switch the mains water supply off instead but fill kettle first.

Then...

If you can find a drain point on a radiator: Make sure the drain point is on the same floor or lower than the item you want emptied for working on (unless a full drain down and then you need to find a drain point on the lowest part of the system). Fix hosepipe to this drain point (with a clamp/jubilee clip unless you live dangerously) and drain off an amount of water to outside drain or garden. Keep draining until you have emptied the rad/s you wish to work on (you will need to open the rad air bleed screws - starting at the top of the house and gradually working down - to allow air in, which in turn allows water out the hosepipe - essentially you are getting rid of a vaccum that would otherwise prevent draining). Take care that you are not just draining a "drop down leg of pipework" - this is okay but don't then go and work somewhere elsewhere on the circuit thinking everywhere is empty. Note that draining down can take quite a while. To check a rad is drained first open the air vent to see if water comes out from the top. If no water comes out then open its drain plug if it has one – if it does not have one then you can carefully start to undo one of the bottom valves from the pipework (with cloths and a water collection tray underneath of course). If anything other than a “last dribble” is apparent then nip the nut tight again sharpish and continue draining.

 

[enigmatic]

thx goldspoon you've been a big help as i need to get this done within the time off work i have as im back thurs

 

[landyandy]

When you have taken the radiator off, remember that the trv could open if the temperature goes below the frost setting temperature.

I would put a 3/4" blanking cap on.

Andy.