25
Replacement of the pump head and assembling
1. Before replacing the valve head check if the valves are
not stuck together by holding the head between two fingers.
You should hear a soft clicking while shaking it carefully.
2. Place the valve head into the valve head top. Check if the
rubber sealing is symmetrical placed in the metal part of
the valve head top. Then snap the glass head into the top
so that the knobs on the glass head fit into the spaces on
the valve head. Place the assembled pump head on the
diaphragms.
Pay careful attention to the arrows on the upper part of the
valve heads. They
must
point in the
same direction
on both
pump heads.
3. Place the setting gauge side number 1 between the metal
top and thread and screw the first screw (a) in so that
the setting gauge can be removed without force. After
the first screw do the same procedure with the screw
(b) and then with the screw (c) and last but not least
again with the screw (d) (Crosswise).
4. If all screws are on the level 1 change to the side 2 of the
setting gauge. Place this side between metal top and
thread and screw the first screw (a) one quarter-turn in.
After this change the setting gauge to screw (b) and
screw this one also a quarter-turn in. Go on with the
screw (c) and (d) in the same way and repeat this
procedure till you can’t remove the setting gauge without
force. Loosen the screw a little bit to take out the setting
gauge and leave the screw on this position.
Hold the short red part of the allen wrench to tighten the
screws, which will provide for the correct tightness.
You should only use screws with a blue spot on the thread.
The blue spot is a Tufloc coating which prevents the screw
from loosening during operation or transportation of the
pump. If you are using a new screw it could be possible
that you need a slightly higher force to screw this in. This
doesn’t matter and doesn’t influence the result of your work.
BÜCHI
Vac
V-500/V-501/V-502/V-503
6 Maintenance
