What Do The Buttons Do - Siemens RWB27Si Instructions Manual

What do the buttons do?

ADV (ADVANCE)
This brings forward the next switching time, for example:-
(a) if your times were ON 7am and OFF 9am - ON 5pm and OFF
10pm and you pressed the ADV at 4pm your heating would
come ON straight away and go OFF at 10pm.
(b) if your times were ON 7am and OFF 9am - ON 5pm and OFF
10pm and you pressed the ADV at 9pm your heating would go
OFF straight away and come ON at 7am the next morning.
+ HRS
This allows you to either increase your heating time in multiples of
one hour (up to a maximum of 3 hours) during a timed ON period
or to bring on the heating in multiples of one hour (up to a
maximum of 3 hours) during an OFF period.