10.Referring to the following screw tightening rotation sequence, securely tighten the three
Allen screws (3) that connect the valve cap (1) to the valve plunger body (13). One at a
time, tighten each screw to first torque. Then continue with the next torque value until the
final value is reached.
– Finger tighten
– 20 inch pounds (2.3 Nm)
– 40 inch pounds (4.5 Nm)
– 60 inch pounds (6.8 Nm)
11.Tighten the three Allen screws (16) that secure the plunger valve body (13) to the cylinder
base (14) to approximately 30 to 40 inch-pounds (3.4 to 4.5 Nm).
NOTICE
Be certain all Allen screws are securely tightened. DO NOT overtighten.
4.4.2
Disassembly and Cleaning
4.4.2.1
M20 Description
This section presents information to disassemble, clean, and rebuild the Model 20 Valve.
Maintenance procedures for the Model 20 valve are grouped into two types, Mini-Maintenance
procedures and Maxi-Maintenance procedures. Mini-Maintenance procedures involve
working on the valve while it is still installed in the analyzer. Maxi-Maintenance procedures
may be used when Mini-Maintenance does not correct a valve fault. However, it is often
cheaper and easier to replace the valve or return it to Siemens for service. This manual covers
the Maxi-Maintenance procedures in the following order.
● Valve Cap Disassembly
● Actuator Disassembly
● Cleaning Actuator, Fittings, Tubing, etc.
● Actuator Assembly
● Valve Cap Cleaning and Assembly
To assure optimum valve operation, a clean contaminant free work environment is required
for this procedure. To repair the valve on site, the customer must have the necessary
maintenance tools and replacement parts. Recommended valve spare parts can be obtained
from Siemens. Recommended tools will include an ultrasonic cleaner and a clean workstation
with lint-free cloth.
It may be easier and less expensive to replace a valve or return it to Siemens for service rather
than perform Maxi-Maintenance.
Valves
4.4 Model 20 Valve
Maxum II Valves and Oven Components
Service Manual, 10/2018, A5E42019844001
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