Servicing
Diaphragm Vacuum Pump N 828 / N 838
50
Translation of original Operating and Installation Instructions, english, KNF 121249-121517 09/19
11. For two-headed pumps:
Pull apart the pump heads and take the pneumatic connec-
tions (
13
) and the O-rings (
14
) (see Fig. 34).
12. For two-headed pumps:
Change the O-rings on both sides of the pneumatic connec-
tion.
13. For two-headed pumps:
Connect the pneumatic connection (with the O-rings) to the
pump heads.
e.) Refit pump head
1. Turn the fan to bring the diaphragm (
8
) to top dead centre.
2. Place the pump head(s) (consisting of intermediate plate (
2
)
with valve plates/sealings (
6
), and head plate (
3
) on the hous-
ing, in the position indicated by the marking (
M
).
3. Gently tighten the screws (
4
), evenly and diagonally.
4. Turn the fan to check that the pump rotates freely.
5. Turn the fan again to bring the diaphragm to top dead centre.
6. Now tighten screws (
4
) firmly (torque: 3.5 Nm).
f.) Final steps
1. Only in the case of DC versions (no cooling fan) and N 838.1.2
KNE: refix the cover (
1
).
2. Connect the pump to the electrical supply.
If you have any questions about servicing call our technical adviser
(contact data: see www.knf.com).
Fig. 34: Extraction of pneumatic
connection and O-rings
