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.

 

[SimonG]

Dump and snatch.

 

[SimonG]

Or just cut old valves off, new insert and new valve over a bucket.

 

[SimonG]

Oh and hope any auto air vents are closed.

 

[MC78]

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!)

Your combi boiler runs from the mains pressure water pipe leading into your property, therefore your system will be pressurized, the tvr and lockshield are the only two components when in locked or off position stopping that pressurized water from spraying out of the pipe work, if you was only going to attach a new radiator to exiting pipe work it is ok to change rad without draining system, but if you are wanting to change the whole of the lockshield and tvr components then draining the system is advised.

 

[Ben-gee]

Do ‘em one at a time and it’ll hold, as long as no aav open, I do it all the time - no need to drain down.

 

[MC78]

Do ‘em one at a time and it’ll hold, as long as no aav open, I do it all the time - no need to drain down.

So if you detach the lockshield off the pipe which is pressurized with water, you will not get wet?

 

[Harvest Fields]

So if you detach the lockshield off the pipe which is pressurized with water, you will not get wet?

Once again. Try it and find out. But I wouldn’t.

 

[MC78]

Once again. Try it and find out. But I wouldn’t.

So I have been disagreed for the right advice

 

[Burger]

So if you detach the lockshield off the pipe which is pressurized with water, you will not get wet?

You relieve the pressure by opening the lockshield after following all other steps I have listed and you wouldn’t get wet. Done it loads of times.

 

[MC78]

You relieve the pressure by opening the lockshield after following all other steps I have listed and you wouldn’t get wet. Done it loads of times.

Would you not need to isolate all other rads to drain only the one as they are all connected? Now I am confused lol

 

[Burger]

Would you not need to isolate all other rads to drain only the one as they are all connected? Now I am confused lol

I have never had to, isolate he flow and return under the boiler, should create a vacuum, plus it’s only for vertical pipes

 

[Ben-gee]

Just open valve and catch the water , shouldn’t be much, then you can cut/ solder whatever you want !
I do this on open vented too just put a 22mm speedfit cap on the vent and a carrot in the feed!
Honestly this is pretty basic stuff i thought we all did.

 

[MC78]

Just open valve and catch the water , shouldn’t be much, then you can cut/ solder whatever you want !
I do this on open vented too just put a 22mm speedfit cap on the vent and a carrot in the feed!
Honestly this is pretty basic stuff i thought we all did.

Well I would rather be safe than sorry, especially on a sealed system.

 

[Burger]

Well I would rather be safe than sorry, especially on a sealed system.

Ok, up to you. Just don’t forget to add some inhibitor after all that water loss and introduction of fresh aerated water.

 

[Ben-gee]

I always use this method if possible, ever since spending hours trying to refill a badly designed system - running round venting and backfilling with mains etc.
In terms of caution, I always have the appropriate sized speedfit cap nearby in case it lets go, and the trusty Charles hoover. Although only needed once, a faulty aav I hadn’t found in back of airing cupboard, this one I drained.

 

[SimonG]

but if you are wanting to change the whole of the lockshield and tvr components then draining the system is advised.

This is the bit I disagreed with. No need at all to drain a pressurised system for a job like this.

 

[king of pipes]

Save yourself alot of grief drain down replace the radiator and fit the new valves . Kop

 

[SimonG]

Would you not need to isolate all other rads to drain only the one as they are all connected? Now I am confused lol

Sums up your lack of knowledge. Unless you know what you are doing then stop making yourself look like a tit by commenting on stuff you obviously know sweet fa about.

 

[Burger]

FYI:

Just changed a 10mm trv today. In and out in approx 20 mins, and that includes cutting old olive off as new nut doesn’t marry up to existing.

 

[Harvest Fields]

FYI:

Just changed a 10mm trv today. In and out in approx 20 mins, and that includes cutting old olive off as new nut doesn’t marry up to existing.

Well done you. Give yourself a giant pat on the back.

 

[Michael1960]

Well done you. Give yourself a giant pat on the back.

Meaning?

 

[Harvest Fields]

Meaning?

Meaning, well done him. For changing a 10mm valve in approx 20 mins with cutting off the olive.

 

[Michael1960]

Well done you. Give yourself a giant pat on the back.

Meaning?

Meaning, well done him. For changing a 10mm valve in approx 20 mins with cutting off the olive.

Pat on the back then

 

[Harvest Fields]

Meaning?

Pat on the back then

Yep, as I said