KNF LABOPORT SH820G Manual De Instrucciones página 146

Servicing
62
If the O-rings (14) cannot be taken out of the connection
tube (10/Changing O-rings), press them together gently
and remove them with pliers if necessary.
4. Loosen the internal head screw (1) on both pump heads.
5. Remove the two pressure plates (2) together with the two
internal head screws (1).
6. Unscrew the gas ballast (9/Fig. 15) from the head plate
(3).
7. Replace the O-ring (13) on the gas ballast (9/Fig. 15).
8. Screw the gas ballast (9/Fig. 15) into the corresponding
head plate (3) as far as it will go. Then turn it back again
until the surface is oriented upwards.
9. Dispose of the replaced O-rings properly.
Replacing valve plates/seals
With the pump, the valve plates/seals (4) are replaced
successively.
1. Remove the head plate (3) from the intermediate plate (6).
2. Remove the old valve plates/seals (4).
3. Carefully clean the intermediate plate (6) (if there are de-
posits on it).
4. Insert the new valve plates/seals (4) into the correspond-
ing seats on the intermediate plate (6).
The valves and O-rings for the pressure side and suction
side are identical; the same applies for the top and bot-
tom of the valves and O-rings.
5. Perform steps 1 – 4 for the second pump head.
6. Dispose of the replaced valve plates/seals (4) properly.
7. Insert the connection tube (10/Fig. 15) back into both head
plates (3).
Fitting the pump head
1. Move the diaphragms (7) to the center position.
2. Press down on the edge of both diaphragms (7) all the
way around.
Translation of Originial Operating Instruction, KNF 325562-325564 02/23
Vacuum system SH820G / SR820G / SH840G / SR840G