Diaphragm pump N85, N86
Troubleshooting
Translation of original Operating and Installation Instructions, english, KNF 121258-121528 01/20
37
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
Condensate has collected in the
pump head.
Detach the condensate source from the pump.
Flush the pump (see Chapter 9.2.1).
Install the pump at the highest point in the system.
Presence of positive pressure
on the pressure side with simul-
taneous vacuum or positive
pressure on the suction side.
Change the pressure conditions.
Cross-section of pneumatic
hoses or connectors too narrow
or restricted.
Disconnect the pump from the system and determine output
values.
Remove restriction (e.g. valve) if necessary.
If applicable, use larger-diameter hoses or connectors.
Leaks in connections, hoses or
pump head.
Make sure the hoses are properly seated on the hose con-
nectors.
Replace leaking hoses.
Eliminate leaks.
Connections or hoses complete-
ly or partially clogged.
Check hoses and connections.
Remove any parts or particles causing blockages, check
filter
Pump head components are
soiled.
Clean head components.
Diaphragm or valve plates are
worn.
Replace diaphragm and valve plates
(see Chapter 9.3).
Diaphragm and valve plates
have been replaced.
Make sure that number and thickness of the diaphragm
spacers correspond to the original delivery state and that
they have been replaced properly onto the diaphragm screw
thread.
Make sure that the pump heads are properly positioned
(N85.3).
Check head connection and hose connections for leaks.
Tab. 20
Fault cannot be rectified
If you are unable to identify the cause of the problem, please send
the pump to KNF customer services (see contact data:
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.
