22
6.2
Flowmeter Disassembly
To access the oval gear rotors, or to remove/replace the meter cap and pulse output
board; undo the meter cap screws (6), and carefully separate the meter cap from the meter
body (1), avoiding misplacing or damaging the O-ring (3) or the rotors (2)
–
when servicing
an EGM004 meter please note that the rotors can stick to the underside of the meter cap
due to liquid surface tension, making it very easy to drop and subsequently damage the
rotors.
The rotors (2) can now be removed and inspected. Take special care to not drop the oval
gear rotors during the service process, as the precision components are very sensitive to
damage.
6.3
Flowmeter Inspection
Inspect O-rings for damage, chemical attack, deformity or any form of deterioration.
Remove, inspect and gently clean the rotors, and check the measuring chamber for damage
or scoring, the rotor shafts should NOT be loose or able to be rotated. Rotors should turn
freely, and should spin without scraping or catching on any part of the meter body. Take
care of the thrust face of the bearings, which protrudes from each end face of the rotors by
a very small amount.
6.4
Re-assembly of Flowmeter
When re-installing the rotors the magnets MUST be correctly positioned so that they are
facing the sensor located in the meter cap; the magnets are inserted from the underside of
the rotor so will not be visible when the rotors are installed, if you can see the magnet
holes with the rotors installed then they are upside-down. If you are unsure of magnet
location it is easiest to test using a small steel object such as a paperclip, steel ruler or small
screw driver.
Both rotors will only engage correctly if fitted precisely at an orientation of 90 degrees to
each other. Rotate the rotors slowly by hand to ensure they are correctly fitted, at the same
time check the rotor shafts & rotor bearings for wear. If you are able to rotate the engaged
rotors through a complete 360, then you have installed them at the correct 90 degree
angle.
Fit the O-ring into the groove and assemble the meter cap onto the meter body; it is
recommended that new O-Rings be used whenever a meter is serviced, particularly if the
