Cleaning Or Replacing The Dosing Diaphragm - Grundfos DMX 221 Installations- Und Bedienungsanleitung

1. Unscrew the valve.
2. Disassemble the valve.
• DN 8, not spring-loaded: Press out the valve cartridge and remove the valve seat from
the ball cage.
• DN 8, spring-loaded: Unscrew the ball cage with a pair of round pliers.
• DN 20: Unscrew the ball cage with a pair of round pliers.
3. Clean all parts and check that the parts are intact.
4. Replace faulty parts with new ones.
5. Replace the O-rings with new ones.
The O-rings must be correctly placed in the specified grooves.
6. Re-assemble the valve.
7. Refit the valve in correct orientation.
The direction arrow on the valve must point in the flow direction (upwards).
Related information
• 7.3 Preparing for maintenance of the dosing diaphragm or the valves
• 7.2 Safety instructions for maintaining the dosing diaphragm or the valves

7.5 Cleaning or replacing the dosing diaphragm

• Observe section Safety instructions for maintaining the dosing diaphragm or the valves
• Observe section Preparing for maintenance of the dosing diaphragm or the valves
1. Unscrew the dosing head screws.
2. Remove the dosing head.
3. Turn the motor fan blades until the diaphragm reaches the front dead centre.
The diaphragm will detach itself from the diaphragm flange.
4. Turn the diaphragm counter-clockwise to unscrew the diaphragm from the tappet.
5. Clean all parts and check that the parts are intact.
6. Replace faulty parts with new ones.
7. Screw in the diaphragm completely. Then turn it back until the holes in the diaphragm and
the flange are aligned.
8. Turn the motor fan blades until the diaphragm reaches the back dead centre.
The diaphragm is moved towards the diaphragm flange.
9. Refit the dosing head.
10. Cross-tighten the dosing head screws with the correct torque.
11. After 6-10 operating hours or two days, retighten the screws with the correct torque.
Related information
• 7.2 Safety instructions for maintaining the dosing diaphragm or the valves
• 7.3 Preparing for maintenance of the dosing diaphragm or the valves
• 9.3.1 Torque values
DMX 221 | | 33