Watson-Marlow 620DuN and 620Du User Manual 91
Close the guard and push it against the track until the latch engages.
Ensure that continuous tubing is not loosely clamped at the pumphead ports.
Ensure that when the pump is re-started all of the rollers have re-engaged. A
roller which has not re-engaged will “click” continuously. No damage will occur
if this happens but the roller should be re-engaged manually using the 5mm
Allen key. See 26 Troubleshooting.
29.8 620RE, 620RE4 and 620R tube element or continuous tube removal
Unlock the guard and disengage the rollers.
Disconnect the tubing from the external pipeline.
Remove the tubing from the pumphead.
29.9 620RE, 620RE4 and 620R maintenance
Scheduled maintenance
The stainless steel pumping rollers run on sealed bearings and do not require
lubrication.
Remove the rotor and lubricate the follower rollers and roller engaging mecha-
nisms with a lithium-based grease. This should be carried out every six months
for intermittent duties and every three months for 24 hour duties.
If fluid is spilled inside the pumphead, flush the pumphead out with water and
mild detergent as soon as possible. If specific cleaning agents are required to
clean the spillage, please consult Watson-Marlow Technical Support Office
before proceeding, in order to confirm chemical compatibility.
If the rotor needs to be removed, refer to the guidelines below.
Roller adjustment
620 pumpheads have provision for adjustment to reset the roller/track gap to com-
pensate for wear after extended service in arduous applications.
Roller/track gaps can only be accurately judged without tubing in the pumphead.
The gap should be 4.6mm for 3.2mm wall tubing and 5.5mm for LoadSure ele-
ments.
If the gap is more than 0.2mm greater than these dimensions, the following may be
carried out:
Note the number on the roller arm to which the engraved line on the hexagon-
headed main roller pin corresponds.
Remove the circlip (snap-ring) and roller pin.
Relocate the main roller pin, resetting the engraved line to one number lower.
For example, if the engraved line was at “-1”, reset it to “-2” to reduce the
roller/track gap.
Always isolate the pump from the mains power
supply before opening the guard or performing
any positioning, removal or maintenance.