Also depending on what TRV's you have fitted (branded?) you can buy and fitted replacement heads with the actual valve body in situ. Just unscrew the TRV head off and screw the new one on. The TRV head is just a temperature controlled actuator that expands and pushes a spring load valve / plunger down to open the flow of water. Taking the TRV head off won't result in any water coming out. You can check if the TRV head is away or if it's the valve / plunger that's buggered by taking the TRV head off and checking is the plunger moves freely manually |