I'm doing some decorating at home and needed to remove the radiator. I still need to be able to use the gas heating throughout the house while the radiator is off.
I closed the TRV and lockshield valve, I then loosened the lockshieled valve nut and proceeded to drain the radiator. Once empty I removed and all was well.
My gas boiler was at 1.5 bar before this work, and 0 after – I expected this. I topped up the boiler pressure slightly to around 0.5 (by opening the valves), then I had a quick look at the radiator pipes and noticed that the lockshield valve side was leaking, a constant dribble of water. The water was coming out of the lockshield valve housing (the threaded part where the radiator connects). Image attached.
Was this because I repressurised the gas boiler?
Should I have capped off this lockshield valve housing somehow one the radiator was removed?
I panicked and put on the radiator again! So, not sure where to go from here really :/ My gas pressure is now at 0 again, although I still had hot water this morning.
Any advice is appreciated.
Best Answer
Seems your TRV was allowing a small flow to maintain the temperature of the (disconnected) radiator.
Try capping the open end of the pipe, the male end in your illustration.
Your local hardware store will have the right sized cap; take a cell-phone photo of the threaded open end with a ruler placed next to it, at the maximum width of the threads. To be certain, do the same with the radiator's end of the connection.
This should stop the TRV's flow (your "leak") and allow your boiler pressure to rise to normal while you have the radiator detached.