Figure 2-2 Siemens And Valco Fittings Compared; Figure 2-3 Siemens Fittings Assembly - Siemens Maxum II PD PA AP Service Manual

Using Small Tubing Fittings
The Siemens fitting compresses the PTFE seal material so that it deforms and fills the space
around the tubing and inside the compression ring and port. The PTFE seal fills in small
scratches in the tubing, and can be replaced without cutting the tubing. The Siemens fitting
can withstand more connect-disconnect cycles than the Valco fitting.
The type of fitting used is application dependent.
Figure 2-2
Assembling Siemens Fittings
The Siemens fitting has a PTFE seal insert that fits over the tube , and is held inside a
compression ring.
1. Slide the nut over the tubing.
2. Slide the PTFE seal over the tubing and towards the tip of the nut.
3. Place the compression collar over the seal so that the tip of the seal protrudes through the
compression collar. The illustration below shows how the parts fit together, along with a
cutaway view of how the compression ring works to create a secure seal.
Figure 2-3 Siemens Fittings Assembly
4. Insert the fitting into the port, making sure that the tubing is seated firmly into the pilot hole.
5. Tighten the nut to finger tight.
6. Then use a small 6 mm wrench to tighten to 1.695 to 1.921 Nm (15 to 17 in-lbs) of torque.
(If the installation is too crowded to use a torque wrench, use a torque wrench on an external
object to get a feeling for the exertion required to produce 15-17 inch-pounds of torque.)
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Siemens and Valco Fittings Compared
Maxum II Valves and Oven Components
Service Manual, 10/2018, A5E42019844001