Replacing radiator without draining down?

[pledgeX]

I've removed a radiator from the wall. The trv and lockshield are still attached to the pipes but turned off. Heating is still on and other rads are still working.

I've got a new radiator, trv and lockshield to fit.

I've read some guides on how to replace the radiator, but they all mention draining the system down, but I'm struggling to work out why.

If I shut off water supply to the boiler, and turn the boiler off, why can't I just take the trv and lockshield off and replace them? The rad is on the top floor, but has flexi pipes so I can easily catch any bits of water still in the pipes when I move them around.

Or would all the other rads on the top floor drain out into the pipes I've just opened? What about if I shut the trvs and lockshields on all of them?

Ive got a combi boiler and the pipes for each rad run directly back to the boiler.

Thanks for any help (as you may have guessed I'm new to this!)

 

[SimonG]

Open vented or sealed system?

 

[Burger]

Open vented or sealed system?

Sealed - he’s got a combi

 

[Burger]

You should be able to isolate the flow and return under the boiler, after draining and removing the radiator, catching any water you can then open up trv side into a bucket and same for lockshield side (count the number of turns - for balancing). Fit new rad and valves, open them up (remembering to count the lockshield side). Open flow and return under the boiler, re-pressurise system, bleed rad and check for leaks.

 

[Aire]

Sealed - he’s got a combi

You never seen an open vented combi?

 

[Burger]

You never seen an open vented combi?

I guess not - I do lack a lot of knowledge due to where I work

 

[Rob Foster]

I've removed a radiator from the wall. The trv and lockshield are still attached to the pipes but turned off. Heating is still on and other rads are still working.

I've got a new radiator, trv and lockshield to fit.

I've read some guides on how to replace the radiator, but they all mention draining the system down, but I'm struggling to work out why.

If I shut off water supply to the boiler, and turn the boiler off, why can't I just take the trv and lockshield off and replace them? The rad is on the top floor, but has flexi pipes so I can easily catch any bits of water still in the pipes when I move them around.

Or would all the other rads on the top floor drain out into the pipes I've just opened? What about if I shut the trvs and lockshields on all of them?

Ive got a combi boiler and the pipes for each rad run directly back to the boiler.

Thanks for any help (as you may have guessed I'm new to this!)

So far so good, do not remove the trv or the the locksheild. just replace the rad and re connect ..maybe using extension diy stuff, then open the valves and re pressurise the system ..to 1.5 bar on the boiler
...when off and cold. its not a good idea especially in winter to trust a trv closed ..because they are a bit thick..and when it gets cold will just open to,heat the room even if there is no rad to feed,...so with no rad to,fill the trv will just dump,the contents of your heating system all over the floor and below
centralheatking

 

[Rakesh]

I usually switch all radiator valves off from the trv’s or any valves that aren’t lock-shields
If accessible, isolate flow and return at the combi boiler
Than drain and change each valve independently. Don’t drain both valves together.
Best way without drain down.
If it’s upstairs rads, then only isolate rads at the same level or above.
Isolating the boiler conserves water in the expansion vessel as long as there isn’t one fitted externally.
External ones are only usually fitted if the internal ones fail and are inaccessible.

 

[Harvest Fields]

Try it and find out

 

[Harvest Fields]

So far so good, do not remove the trv or the the locksheild. just replace the rad and re connect ..maybe using extension diy stuff, then open the valves and re pressurise the system ..to 1.5 bar on the boiler
...when off and cold. its not a good idea especially in winter to trust a trv closed ..because they are a bit thick..and when it gets cold will just open to,heat the room even if there is no rad to feed,...so with no rad to,fill the trv will just dump,the contents of your heating system all over the floor and below
centralheatking

If changing rad. Always change valves.