4.0 MAINTENANCE
CAUTION:
Before working on the pump, disconnect the power cord, depressurize the
discharge tubing and drain or flush any residual liquid from the pump head and valves.
Always wear protective gear when working around chemicals.
4.1 Diaphragm
Replacement
Disconnect AC power to the pump and disconnect the suction tubing and discharge
tubing. Remove the four head bolts with a 4mm hex wrench. Turn the stroke length knob
fully counter-clockwise. Unscrew the diaphragm and remove its retainer (small disk
behind the diaphragm).
CAUTION: There may be small brass spacers between the
retainer and the armature shaft. These spacers need to be re-used when replacing the
diaphragm.
Install the new retainer and diaphragm on the shaft. Turn the diaphragm
clockwise until it bottoms on the shaft. Replace the pump head and tighten the head bolts
to a torque of 19 lb-in (2.16 N-m).
4.2 Valve
Replacement
Making sure the discharge side has been depressurized, remove the suction and discharge
tubing. Remove the suction fitting, two valve cartridges*, o-ring and gasket(s). Install the
new o-ring, gasket(s) and valve cartridges. Be sure both valve seats are in the same
orientation. Refer to Figure 9 below. Tighten the suction fitting. Similarly remove and
replace the discharge valve cartridges, o-ring and gasket(s).
*EHE45 and EHE55 series have one valve cartridge on the suction and discharge sides.
Refer to Section 5.0 for exploded view drawing and parts list.
FLOW
Valve Guide
Ball
Valve Seat
Gasket
Figure 9 Valve Cartridge Orientation
4.3 Tubing
Check ends of tubing for splits, cracks or thin spots. Examine the full length of tubing for
damage due to chafing, abrasion, stress cracks, excessive temperature or exposure to
ultraviolet light (direct sunlight or mercury vapor lamps). If any signs of deterioration
exist, replace the entire length of tubing. It is a good idea to replace discharge tubing on a
regular preventative maintenance schedule every 12 months.
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