POLAR S720i - Manual (Page 92)

Detach the sensor from your bicycle.
1. Open the sensor by removing the two small screws, counter-clockwise,
with a small screwdriver.
2. Lift the case off carefully. Hold the sensor cover upwards so that the
PCBA (printed circuit board assembled) stays in the case.
3. Remove the PCBA carefully.
4. Press the battery holder gently. Release a hook of the holder from
the opposite side of the PCBA and lift the holder upwards. Remove
the old battery.
5. Insert a new battery with the plus (+) side facing up and press the
battery housing gently so that it is attached to the PCBA at all corners.
6. Put the PCBA back into place.
7. Check that the sealing ring stays in its groove. Replace the cover back.
8. Insert the two screws in their holes and tighten them gradually in turn.
9. Test the sensor by checking that it gives out an orange flash when the
spoke magnet passes the speed sensor.
10. Do not throw the replaced battery away with normal waste; take it to a
place where problem waste is handled.
Service
Should your Polar heart rate monitor need service, see Customer Care
Charter to contact an authorised Polar Service Centre.
Water resistance cannot be guaranteed after unauthorised service.
G 90