Siemens VRD Series - Operation

Technical Instructions VRD4 Series Double Valves
Document Number CC1N7649us
September 08, 2016
Page 6 Siemens AG Building Technologies Division
Operation
All VRD40.xxxUx gas valves are normally closed, two-way valves. The valves have a standard,
integral, stainless steel mesh filter (0.9 mm) in the inlet to protect the downstream
components against contamination.
VRD40.xxxUx double valves consist of two valves in series. Each valve has a double seat to
achieve high flow (see Figure 1).
All valves have ¼-inch NPT ports for pressure test connection. A full size vent connection plate
is available as an accessory.
See Table 2 and 3 for details on ports and vent connection plates.
7649z02/0514
V
1
V
2
Figure 1. Sectional view of VRD40.065UF
Closing springs:
Each double seat uses one pair of springs. The spring forces act separately as closing forces on
the individual valve seats.