Does the thero valve come off without the need to drain system by turning the twist grip connector
The valve turns but does not work is it repairable

Bruce, February 2010

are we talking about your TRV not working ?
before changing the valve undo the knurled ring under the trv head and see if the plunger pin is stuck down, this will prevent the radiator from heating up , gentle taping it on side sometimes works, or a spray of WD 40 ensure pin is free before reattaching the TRV head

wirecutterman, February 2010