User Guide

Technical Instructions
Document No. 155-086P25
March 7, 2005
Page 2 Siemens Industry, Inc.
Specifications
Valve Body
Valve size/capacity See Table 2.
Valve body style Flared End
Valve action Upper seat normally closed
Bottom seat normally open
Valve stroke 3/8-inch (9.5 mm)
Valve body rating 300 psig @ 350°F
(2068 kPa @ 177°C)
Flow characteristic (B port) Modified equal percentage
Valve Actuator
Nominal spring span 5 psi (34.5 kPa)
Effective diaphragm area 3.4 inch
2
(21.9 cm
2
)
Maximum air supply to diaphragm 30 psig (207 kPa)
Air connection 1/8” N.P.T.
Standard spring ranges P=10 psi (68.9 kPa)
3 to 8 psi (20.7 to 55.2 kPa)
10 to 15 psi (68.9 to 103.4 kPa)
Operating
Controlled medium Water, Ethylene glycol solution
Maximum fluid temperature 250°F (121°C)
Maximum inlet pressure 300 psig (2068 kPa)
Maximum recommended differential pressure for
modulating service
Between inlets 25 psi (172 kPa)
Between inlet and outlet 25 psi (172 kPa)
Shipping weight 2.0 lb (0.9 kg)
Dimensions See Figure 3.
Table 2. Maximum Water Capacity - US Gallons per Minute.
Valve
Size
(inches)
Pressure Differential - psi
C
v
1
2 3 4 5 6 7 8 9 10 11 12 13 14 15 20 25
1/2 1.5 2.1 2.6 3.0 3.4 3.7 4.0 4.2 4.5 4.7 5 5.2 5.4 5.6 5.8 6.7 7.5
1/2 2.5 3.5 4.3 5.0 5.6 6.1 6.6 7.1 7.5 7.9 8.3 8.7 9 9.3 9.7 11.2 12.5
Applications
VP 656 Three-way Mixing Valves are recommended for mixing hot or chilled water for
convectors, fan coil units, unit conditioners, radiation, reheat coils, and similar terminal
units requiring water mixing. The dual sealing packed construction allows applications
for higher pressure system encountered in high rise buildings.
Applications requiring a modified equal percentage flow characteristic must be piped so
the NO port controls the flow to the coil.
Typical uses are schools, office buildings, hotels, hospitals, factories, and other sites
where efficient, economical water mixing is desired. The small, overall size lends itself
to installation within cabinet enclosures, etc., where available space is limited.