Watson Marlow Pumps 604U, Manual, Page: 4 / 13

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Rear panel recess
The pump rear panel recess houses the following:
1 Signal offset potentiometer 2 Tachometer switch 3 Fuse holder 4 Terminal block 5 Voltage selection switch 6
Signal range potentiometer 7 Signal overload LED.
Troubleshooting
Should the pump fail to operate, make the following checks to determine whether or not servicing is required.
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Check that the power switch is on.
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Check the mains supply is available at the pump.
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Check the voltage selector switch is in the correct position.
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Check the fuse in the mains socket.
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Check that the pump is not stalled by incorrect fitting of tubing.
Manual operation
Set the Auto/Manual/Max switch to Manual .
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Start up direction Start the pump by turning the Forward/Off/Reverse switch to the required direction of rotation.
The preferred direction of rotation is clockwise (with fluid entering at the bottom of the pumphead), which will ensure
the longest possible tube life. To operate against higher pressures use anticlockwise rotation.
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Prime To prime the pump at maximum speed turn the Auto/Manual/Max switch on the front panel to its Max
position. When released the switch will return to its manual position.
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Speed control The speed setting dial is calibrated in percentage of maximum speed and has a locking knob to
prevent accidental speed changes.
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Stop Stop the pump by turning the Forward/Off/Reverse switch to its central Off position. To change the
direction of flow, turn the Forward/Off/Reverse switch to its central Off position until the pumphead rotor stops,
and then turn it to the required direction of rotation.
If returning from auto control to manual control, it is not necessary to disconnect the process signal from the pump or
adjust the calibration potentiometers.