Removing the piston seal (16):
1.
Clamp the piston (10) at the piston head
(10.1) without damaging.
2.
Screw out the piston guide (10.2).
3.
Remove the piston seal (16).
Assembling the back pressure valve:
Assemble the back pressure valve using
a reverse sequence of steps.
Tab. 1: Tightening torques
Threaded connection
Value
Piston guide / piston head
DN10 / DN15
3 Nm
Piston guide / piston head
DN20 / DN25
4 Nm
Piston guide / piston head
DN32 / DN40
5 Nm
Housing screws tightening torque
Threaded connection
Value
Housing screws DN10 / DN15 /
DN20 / DN25 *
6 Nm
Housing screws DN32 / DN40 *
8 Nm
* greased
Check the tightening torque of the
housing screws after 24 hours' opera‐
tion.
Carrying out repairs
53