Maintenance; General Notes; Maintenance Intervals; Cleaning Suction And Discharge Valves - Grundfos DDI 222 Installation And Operating Instructions Manual

10. Maintenance

10.1 General notes

Warning
When dosing dangerous media, observe the
corresponding safety precautions!
Risk of chemical burns!
Wear protective clothing (gloves and goggles) when
working on the dosing head, connections or lines!
Do not allow any chemicals to leak from the pump.
Collect and dispose of all chemicals correctly!
Warning
The pump housing must only be opened by
personnel authorised by Grundfos!
Repair must only be carried out by authorised and
qualified personnel!
Switch off the pump and disconnect it from the power
supply before carrying out maintenance work and
repair!

10.2 Maintenance intervals

In the event of a diaphragm leakage, the dosing
liquid may leak out of the hole in the intermediate
flange between the pump and the dosing head. The
parts inside the housing are protected from the
dosing liquid for a short time (depending on the type
of liquid) by the housing sealing. It is necessary to
Caution
check regularly (daily) if liquid is leaking out of the
intermediate flange.
Observe section 10.5 Diaphragm breakage
For maximum safety, we recommend the pump
version with diaphragm leakage detection.
• At least every 12 months or after 4,000 operating hours. When
dosing crystallising liquids, more frequently.
• In the event of a fault.
10.2.1 Cleaning
• If necessary, clean all pump surfaces with a dry and clean
cloth.
10.2.2 Cleaning the valves and diaphragm
• Clean the diaphragm and valves and replace, if necessary (for
stainless-steel valves: inner valve parts).

10.3 Cleaning suction and discharge valves

If possible, rinse the dosing head, e.g. by flushing it
Note
with water.
10.3.1 Switching off the pump
1. Switch off the pump and disconnect it from the power supply.
2. Depressurise the system.
3. Take suitable steps to ensure that the returning dosing
medium is safely collected.
48
10.3.2 Unscrewing suction and discharge valves / cleaning
valves
1. Unscrew the suction and discharge valves.
2. Remove the screw part and valve seat with round nose pliers.
3. Dismantle the inner parts.
4. Clean all parts. Replace faulty parts by new ones.
– For plastic DN 8 valve, replace the valve completely.
– For stainless-steel DN 8 valve or DN 20 valve, replace the
inner valve parts.
5. Re-assemble the valve.
6. Replace the O-rings by new ones. Refit the valve.
Stainless
steel
Fig. 54 Stainless-steel or plastic DN 20 valve, spring-loaded
as an option
Stainless
1)
steel
Fig. 55 Stainless-steel or plastic DN 20 valve, spring-loaded
as an option
The O-rings must be correctly placed in the specified
groove.
Caution
Observe the flow direction (indicated by an arrow on
the valve body)!
Only tighten the valve by hand.
Plastic
Plastic 2)