As we may or may not be aware every Monday at 12 noon (local time) TRVZBs go through the CA process which opens and closes the mechanical TRV valve. 100% open and 100% closed. My topic for discussion is do we feel that 168 hours between CA events is the right period to exercise all types of mechanical valves to prevent them sticking or should the period be user defined for individual TRVZBs ? From experience we have found that some makes of TRV if held closed for longer than 24 hours (especially in rooms that don’t often require to be heated) will stick in the closed position despite regular lubrication maintenance of the valve pins. As a workaround for the problem we have employed system linked stand -alone hardware timing pulse generators to trigger scenes that take the TRVZBs through ‘Heating’ and ‘Keeping’ cycles. I would appreciate to have other Forum members thoughts and experiences on this subject of exercising the mechanical element of a TRV. Thanks