SUUNTO HELO2 - Manual (Page 97)

When the battery is re-installed, the transmitter sends an overpressure (“---“)
signal on code 12 for 10 seconds, after which it goes to normal operation, and
shuts down after five (5) minutes.
9. Check that the new lubricated O-ring is in good condition. Put it in the right position
in the O-ring groove. Be very careful not to get any dirt on the O-ring or its sealing
surfaces.
10. Carefully put the transmitter cover into place. Note that the cover will only fit in
one position. Match the three slots on the inside of the cover with the three ledges
below the battery.
11. Screw the four screws back into place.
Wireless transmitter parts. The code stands for spare part order number.
97