Hi
Please see attached image. The builder left the radiator valve like this. I have a TRV to go on, but I expected the cap would just unscrew and I would screw the TRV on. When I loosened the cap, water spurts out from the system. Do I need to drain the whole system to fit the TRV??
Please see attached image. The builder left the radiator valve like this. I have a TRV to go on, but I expected the cap would just unscrew and I would screw the TRV on. When I loosened the cap, water spurts out from the system. Do I need to drain the whole system to fit the TRV??