TCV's? I presume you mean TRV's... Take the thermostatic heads off them and check to make sure the pin's are not jammed down...
Most plumbers install rads on a two pipe system (Parallel), however sometimes rads are installed on one-pipe systems (Series) - Especially older systems where by removing a rad, you will break the flow and prevent the other's heating up.
Generally speaking you will never have a TRV fitted on a one-pipe system though, as when one rad shuts off, so would all the others unless there was a by-pass fitted... Some centre-fit, single entry TRV valves had this by-pass included into their design, but as you may have guessed, once the rad was removed, the water would flow through the by-pass and the rest of the rads would continue to heat up....
Basically - Check your TRVs and give them a whack if they need it.
GasAid.co.uk, December 2006
