Watson-Marlow 720UN and 720SN User Manual
70
UN, SN
25 Pumphead fitting
25.1 Removing and refitting
the pumphead
The procedure for removing and refitting the pumphead is the same for 720R and
720RE pumps.
Removing the pumphead
From the pumphead remove:
the track securing bolt and the track
the M8 x 157mm socket head cap screws from the bottom left and bottom right
of the pumphead front plate
the M8 x 16mm socket head cap screws from the top left and top right of the
pumphead back plate
Pull the pumphead away from the pump drive. The coupling halves will sepa-
rate, leaving the coupling spider attached to one of the coupling halves. This can
easily be removed by hand for cleaning or renewal.
Refitting the pumphead
Reposition the coupling spider on the drive-side coupling half.
Hand-rotate the pumphead coupling half until its rotary position aligns with the
rotary position of the drive coupling half.
Align the pumphead and the drive so that the two coupling halves will mesh
when pushed together. (If the pumphead foot is in place, the pumphead will be
correctly positioned vertically; if the pumphead is visually centred on the drive’s
mounting plate, the pumphead will be correctly positioned horizontally.)
Push the pumphead and the drive together. The pumphead is correctly posi-
tioned when no gap is visible between the pumphead back plate and the drive
mounting plate.
Apply thread-locking compound to the M8 x 157mm socket head cap screws and
reposition them at the bottom left and bottom right; repeat with the M8 x
16mm socket head cap screws at the top left and top right. Tighten all four in
sequence.
Reposition the track and the track securing bolt.
