Open up those TRVs for the summer
We often get called to attend to properties in the autumn where a single radiator or two are not working. Quite often this is due to sticking thermostatic radiator valves. A thermostatic radiator valve has a rubber seating on a spring which gets depressed by the valve head, if this seating is left in the depressed (off) position for a prolonged period it can often become stuck, resulting in the radiator not getting hot.
To prevent this from happening you can ensure that all TRV valves are left in the fully open position for the summer months when the heating is normally switched off anyway.