Child lock . . .
I have a room with two TRVs in it. One of the TRVs controls the room's temeperature with the other slaver to it. On the control TRV I am able to select child lock however on the slave the child lock option is not shown.
Unfortunately (as I discovered this afternoon) if the slave TRV is operated manually it then takes over control of the room temperature, opening both itself and the master TRV.
I've realised that one of the TRVs (VA2049976064, the control) is running firmware 79.1 whilst the other (VA3524666880, the one lacking child lock) is on 66.4. Could you advise on how to get it to update please ?