Radiator valve replacement

We had a radiator that had been through a bit of tough time and had been involved in a collision with a heavy object that had accidently collided with the valve and smashed the top off! There was nothing more to be done than replace the damaged valve and pipe.

Luckily I had a shiney new Thermostatic Radiator Valve (TRV) in my plumbing spares storage box so didn’t need to source a new one. Some old valves are not thermostatic (adjust the radiator temperature automatically depending on the numbered setting on the radiator head) and are simply manually adjustable ones.

I gathered the relevant tools and materials in preparation for tackling the job in hand. They were:

  1. Adjustable wrench
  2. 22mm spanner
  3. Three legged radiator valve key (for releasing pressure before and bleeding the rad after the job is complete)
  4. Pliers
  5. Anaerobic thread-locker
  6. Old towels
  7. 10mm pipe cutter
  8. 10mm push-fit stop end
  9. 10mm push-fit coupler suitable for central heating systems
  10. Pipe bender tool
  11. ½ inch BSP coupling valve
  12. 10mm copper pipe
  13. Reel of 10mm microbore copper pipe
  14. 10mm internal pipe bending spring
  15. Tray for catching the water from the radiator.

First of all I closed the lock-shield valve by taking the plastic cap off of the lock-shield and the using a pair of pliers to turn the flat faced spindle coming out of the lock-shield body in a clockwise direction. In my case it was seized so I had to release the locking nut slightly to get purchase on the spindle and make it turn.

lock shield valve
Lock shield valve
lock shield with protective cap removed
Lock shield with protective cap removed

Then using the three-legged radiator key I turned the bleed valve at the top of the radiator in order to release any pressure that had built up in the radiator catching any outflow with one of the old towels gathered at the beginning of the job.

tray for catching drips from radiator
Tray for catching drips from radiator

Because of the accident that had happened with the radiator valve the 10mm microbore pipe that feeds the radiator used in our central heating system got damaged requiring it to be repaired. So with the tray under the radiator feed pipe, I cut the pipe using the pipe cutter and quickly pushed on the push fit stop end stemming the flow from the pipe.

freeing off seized lock shield valve
Freeing off seized lock shield valve
adjusting lock shield valve
Adjusting lock shield valve

Then I undid and demounted the feed pipe into the valve and unscrewed the valve from the radiator. I then inserted the ½ inch BSP valve coupling with valve closed just as a temporary measure to stop the water from coming out of the radiator.

undoing radiator valve BSP fitting
Undoing radiator valve BSP fitting

I measured the length of replacement pipe I would need allowing for the bend into the valve and cut the pipe to length. Then using the pipe benders and the internal pipe bending spring I put a reasonably tight semi-circle into the end of the pipe to go up into the valve. I offered up the newly cut pipe and trimmed both ends to match the required fittings in either end of the pipe.

temporary BSP valve coupling
temporary BSP valve coupling
pipe bending tools
pipe bending tools
10mm microbore pipe bending coil spring
10mm microbore pipe bending coil spring

Applying a small amount of anaerobic thread-locker I inserted the pipe into the 10 to 15mm converter that goes into the valve and tightened it up. The thread-locker stays open until it is deprived of air at which pint it goes hard in a matter of seconds.
At this point I removed the stop end from the cut supply pipe and put the 10mm push fit coupling onto the fed pipe and then pushed the pipe from the valve into it.

I then removed the temporary ½ inch BSP valve I had inserted into the rad and let the water run out until it abated applying some anaerobic thread-locker at this point to the ½ inch BSP fitting on the valve and screwing up the nut around it from the radiator making sure the valve was in the upright position.

Having left the joints to set for 3 hours the final part of the job was to bleed the radiator and open the lock-shield by a quarter of a turn ant-clockwise then fully opening the TRV before turning on the central heating. Keeping an eye on the new joints to make sure there were no leaks until the radiators reached maximum temperature.

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