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Troubleshooting
Vacuum Pumps N 920 APE-W and N 920 APDC-B
38
Translation of original Operating and Installation Instructions, english, KNF 121690-121708 09/19
Flow rate, pressure or vacuum too low
The pump does not achieve the output specified in the Technical data or the data sheet.
Cause
Fault remedy
Connections or lines completely
or partially clogged.
➔
Check connections and lines.
➔
Remove the clogging parts and particles.
Head parts are soiled.
➔
Clean head components.
Diaphragm or valve plates are
worn.
➔
Replace diaphragm and valve plates (see Chapter 9.3).
Replaced diaphragms and
valve plates.
➔
Check that the spacers have been replaced onto the dia-
phragm screw thread.
➔
Check head connection and hose connections for leaks.
➔
Possibly carefully tighten the screws of the head cover
crosswise.
Tab. 20
Fault cannot be rectified
If you are unable to determine any of the specified causes, send
the pump KNF Customer Service (contact data: see www.knf.com).
1. Flush the pump (see Chapter 9.2.1).
2. Clean the pump (see Chapter 9.2.2).
3. Send the pump, together with completed Health and Safety
Clearance and Decontamination Form, to KNF stating the na-
ture of the transferred medium.