ABB CoreSense M10 Installation Manual page 39

To purge the sensor head:
1 Remove the external sampling port cover located on top of the sensor with the 4 mm hex key.
2 Connect the provided bleeding hose (ID 3.18 mm [0.125 in]) to the sampling adapter.
3 Direct the other end of the bleeding hose in an oil container to collect all the purged oil.
4 Slowly open the transformer valve and wait until oil comes out of the sensor (about 20 seconds; this
ensures that all air is purged).
NOTICE
Make sure that the transformer is in positive pressure before opening the transformer
valve.
Make ABSOLUTELY SURE that there are no bubbles left in the bleeding hose.
Installing the sensor head
39