
Diaphragm Vacuum Pump N 828 / N 838
Operation
Translation of original Operating and Installation Instructions, English, KNF 121249-121517 09/19
33
Excessive pressure can be prevented by placing a bypass line
with a pressure-relief valve between the pressure and suctions
sides of the pump. For further information, contact our tech-
nical adviser (contact data: see www.knf.com).
For pumps with AC motor:
WARNING
Automatic starting can cause personal injury and
pump damage
When the operation of the pump is interrupted by the
thermal switch, the pump will restart automatically af-
ter cooling down.
Take all necessary care to prevent this leading
to a dangerous situation.
With the pump at a standstill, open pressure and suction lines
to normal atmospheric pressure.
The life of the diaphragm is prolonged the formation of condensate
is avoided. Therefore the following precautions should be taken:
Run the pump for a few minutes to warm it up before handling
saturated or nearly saturated vapors.
KNF recommends: When transferring aggressive media, flush
the pump prior to switch off (see Chapter 8.2.1) to increase the
service life of the diaphragm.
For pumps with AC motor:
The pump may not start up against pressure or vacuum during
switch-on. This also applies in operating following a brief power
failure. If a pump starts against pressure or vacuum, it may
block. This activates the overload switch and the pump
switches off.
For pumps with DC motor:
The pump may not start up against pressure or vacuum during
switch-on. This also applies in operating following a brief power
failure. If a pump starts against pressure or vacuum, it may
block.
Install overload switch (see Chapter 6.2).
Make sure that there is no pressure in the hoses before switch-
ing on the pump.
For pumps with brushless DC motor:
The pumps may start against pressure or vacuum. This also al-
lowed if you experience a brief power interruption.
Restore the system to normal atmospheric pressure (release
pneumatic pressure in pump).
Pump standstill
Vapors as media
Switching on the pump
Switching off the pump /
removing from operation