Replace The Valve Rotor - Hach APA 6000 Maintenance Et Dépannage

Replace the valve rotor

To prevent valve leakage, replace the valve rotor and inspect the valve
stator for wear or scratches. Valve leakage can quickly cause damage to
the rotary valve body due to corrosion of internal parts.
Items to collect:
7
• Allen wrench, / -in.
64
• Valve rotor
• Valve stator
1. Put the analyzer in shutdown mode. Refer to
shutdown mode on page 5.
2. Open the reagent enclosure and standard/cleaning solution
enclosure. Put a paper towel on the bottom of each enclosure lid.
3. Remove the bottle caps and tube assemblies from all the analyzer
bottles to prevent siphoning. Put them on the paper towel to absorb
any drips or leakage.
4. Stop sample flow to the analyzer.
5. Remove the valve stator. Refer to
a. Remove the tube fittings from ports 4, 7 and 10 of the rotary valve
to get clearance for the allen wrench.
b. Use the allen wrench to loosen the three recessed socket head
cap screws in the valve stator. Be careful not to lose the screws
or the spacer ring that the screws hold in position. Remove the
spacer ring and screws and keep for later use.
c. Pull the valve stator away from the valve module. About 2–3 mL
of fluid may drain from the valve stator. If the volume is large,
make sure that the tubes where removed from the analyzer
bottles.
6. Remove the used valve rotor. Refer to
the rotary valve with a paper towel.
7. Install a new valve rotor.
8. Dry and inspect the surfaces of the valve stator.
10 English
Put the analyzer in
Figure 4.
Figure 4. Dry all surfaces of
9. If the rear surface of the valve stator has circular grooves or excess
wear, replace the valve stator.
a. Remove all the tube fittings from the valve stator.
b. Discard the valve stator.
10. With the spacer ring in position, install the valve stator.
a. Position the valve stator with port 1 at the 12 o'clock (top center)
position on the valve body.
b. Make sure that the locating pins in the valve body align with the
locating pin holes on the back side of the valve stator.
c. Hold the valve stator in position. Install and turn the socket head
cap screws to tighten. Refer to
increments until the valve rotor and valve spacer are seated on
the valve body (100 to 120 inch-ounces of torque or 0,7 to
1,4 Joules of torque). Do not over-tighten or valve damage will
occur.
Note: An even resistance is felt as the socket head cap screws are
tightened because an internal spring washer is being compressed.
11. Install the removed tube fittings in the rotary valve. Fittings should be
securely finger tightened. Do not over-tighten the fittings because
that will pinch the tubing at the ferrule and slow or stop liquid flow
through the tube.
If a fitting has been over-tightened, cut off the pinched end of the
tube and use a new ferrule.
Note: In some cases, a tool may be necessary to tighten a fitting a maximum
of ¼ turn. If leakage continues, the valve stator or valve fitting may require
cleaning or replacement. Loose fittings result in air or liquid leaks and poor
analyzer performance.
12. Install the bottle caps and tube assemblies in the analyzer bottles.
a. Make sure that 12.7 mm (0.5-in.) of the tubing comes out of the
bottom of each straw.
b. Install the correct bottle cap and tube assembly on each analyzer
bottle. Each tube has a label that identifies the corresponding
analyzer bottle.
c. Close the reagent enclosure and standard/cleaning solution
enclosure. Discard the used paper towels.
13. Start sample flow to the analyzer.
Figure 4. Tighten in even