Procedure for replacing a radiator and valves

[nrage147]

Downstairs radiator, upstairs combi boiler, no tanks.

I just wanted to check that this order of steps was correct...

1. Turn off combi boiler.
2. Open bleed valve on rad to be replaced, to decrease total system pressure.
3. Isolate all upstairs radiators by closing one valve fully.
4. Isolate both radiator valves, and drain radiator.
5. Remove radiator and fixing.
6. Insert new radiator cap, bleed valve, and tails.
7. Measure up and fit new radiator to wall in correct position.
8. Make new valves ready w/ jointing compound (inside where olive meets), and set in closed position.
9. Swap old valves for new valves (hopefully reusing the old olive and nut).
9b. If needed, remove olive with hacksaw, clean pipe, and replace with new olive and nut and jointing compound.
10. Re-attach valves to radiator tails (here I may need to cut tail and/or use extensions, not sure of precise measurements as old rad is imperial)
11. Make sure all fitting are tight.
12. Open valves (check for leaks).
13. Turn on boiler, re-pressurize, and final test (fingers crossed).

 

[terryplumb]

If you intend to remove the valves from pipework and amend pipework you should drain the system first. Closing one valve on every upstairs radiator is totally pointless.

 

[nrage147]

If you intend to remove the valves from pipework and amend pipework you should drain the system first. Closing one valve on every upstairs radiator is totally pointless.

I admit, this came from youtube. Apparently it should prevent the water flowing out, enough to swap over the valves. It seemed to have worked, though it's possible I just drained most of the system out the valves on this radiator in the process

 

[Notch7]

(hopefully reusing the old olive and nut

Not worth it

I never know whether brass or copper olives are best….

3. Isolate all upstairs radiators by closing one valve fully.
4. Isolate both radiator valves, and drain radiator.
5. Remove radiator and fixing

As you are changing old rad to new, the pipework will need altering and unless you drain down the pipework under the floor will still be full of water.

It’s not that much of a drama draining the system and refilling….better than getting wet.

Re-attach valves to radiator tails (here I may need to cut tail and/or use extensions, not sure of precise measurements as old rad is imperial)

If you lean the new rad against a wall, fit the radiator tails and hand screw on the angled radiator valves, you can your tape measure across and measure the centres….so you can then decide how to alter the pipework to suit

If you can take up a floorboard it’s often quite easy to adjust the pipework, depending which way they run, sometimes you just need to shorten or extend.

and if you haven’t got a pipe bender, re use the part with the bend. If the olive has been crushed into the pipe, I’d replace that bit of pipe.

 

[nrage147]

Not worth it

I never know whether brass or copper olives are best….


As you are changing old rad to new, the pipework will need altering and unless you drain down the pipework under the floor will still be full of water.

It’s not that much of a drama draining the system and refilling….better than getting wet.


If you lean the new rad against a wall, fit the radiator tails and hand screw on the angled radiator valves, you can your tape measure across and measure the centres….so you can then decide how to alter the pipework to suit

If you can take up a floorboard it’s often quite easy to adjust the pipework, depending which way they run, sometimes you just need to shorten or extend.

and if you haven’t got a pipe bender, re use the part with the bend. If the olive has been crushed into the pipe, I’d replace that bit of pipe.

Yeah, replacing an old imperial rad for a new metric (1300mm) one. I can't adjust the pipework as 1) it's laminate flooring and 2) I haven't the tools/expertise to solder pipe.. I would like to learn how, but.. I want to move some radiators upstairs and I think I might investigate using push fit.

 

[ChrisJP]

I admit, this came from youtube. Apparently it should prevent the water flowing out, enough to swap over the valves. It seemed to have worked, though it's possible I just drained most of the system out the valves on this radiator in the process

It's the valves being closed that prevents water flowing into the radiators, they don't prevent any water flowing if you remove them!
If you need to change the valves you must drain the system down, otherwise water will pour out of the pipe stub ends when you remove the valves. A possible alternative is to use a pipe freezing kit but this is really only feasible if you just need to replace one valve and don't want to drain the system. If you're replacing all the valves then you'd need a freezing kit for each valve which will be uneconomical.

 

[nrage147]

Success!

 

[nrage147]

It's the valves being closed that prevents water flowing into the radiators, they don't prevent any water flowing if you remove them!
If you need to change the valves you must drain the system down, otherwise water will pour out of the pipe stub ends when you remove the valves.

I closed the valves on the rads upstairs which, AIUI, prevents the water flowing out as it would have to pull/defeat a vacuum to do so (even though it's higher up in the system and gravity is trying to force it out). I did bleed off all the system pressure before I started, using the bleed valve on the rad being replaced. I think I probably ended up emptying most of the pipes, but not the rads.