POLAR F4 - Manual (Page 22)

Troubleshooting
If you don't know where you are in the menu,
press and hold BACK until the time is displayed.
If there are no reactions to any buttons, reset the
wrist unit by pressing all the buttons
simultaneously for two seconds. All other settings
except time and date will be saved.
If the heart rate reading becomes erratic,
extremely high or shows nil (00), make sure no
other heart rate transmitter is within 1 m/3 ft, and
that the transmitter strap fits snugly and the
electrodes of the transmitter are moistened, clean
and undamaged.
Strong electromagnetic signals can cause erratic
readings. If the abnormal reading continues
despite moving away from the source of
disturbance, slow down and check your pulse
manually. If you feel it corresponds to the high
reading on the display, you may be experiencing
cardiac arrhythmia. Most cases of arrhythmia are
not serious, but consult your doctor nevertheless.
A cardiac event may have altered your ECG
waveform. In this case, consult your physician.
If heart rate measurement does not work despite
the actions mentioned previously, the battery of
your transmitter may be empty. For further
information, see chapter Caring for Your Heart
Rate Monitor.
E N G L I S H
22 Customer Service Information