Technical Instructions
VVP45… and VXP45... Series Two-port and Three-port Seat Valves
Document Number CM1N4845E-P25
ANSI Class 250
Rev. 4, February, 2002
Page 4
Siemens Building Technologies, Inc.
Engineering Notes
Recommendation,
Continued
AB
A
B
AB
A
B
SV
AL0070R1
Figure 2. VXP45.
Three-port valves VXP45…
Use as mixing valves only.
Mixing: flow from A
and B
→
AB.
AB =
Constant total flow
(outlet).
A = Variable
flow
A
→
AB (inlet A).
B = Variable
flow
B
→
AB
in
bypass
(inlet
B.)
Stem retracted: Path A
→
AB
open, bypass B closed.
Stem extended: Path A
→
AB
closed, bypass B open.
Also see Mounting Notes and Commissioning Notes.
Mounting Notes
SV
AL0072R1
Permitted
Not
Permitted
Figure 3. Mounting Positions.
See Engineering Notes for flow direction.
The valves are always supplied in a common package with installation instructions.
The valves are automatically closed by a return spring. The straight-through port
A
→
AB of the valve is opened by adjusting the manual knob or actuator; with three-
port valves, bypass B is throttled or closed. The manual adjusting knob only permits
opening to 70% (bypass 30% open)
Commissioning
Notes
Manual Adjustment
Two-port valves VVP45…
Spindle retracts: throughport from A
→
AB opens
Valve spindle extends: throughport from A
→
AB closes.
Three-port valves VXP45…
Spindle retracts: throughport A
→
AB opens, bypass B closes
Valve spindle extends: throughport A
→
AB closes, bypass B opens.
WARNING:
Before performing any service work on the valve and/or actuator, do the
following:
1. Switch OFF pump and power supply.
2. Close the main shutoff valve of the piping system.
3. Release pressure and allow to cool down completely.
4. Disconnect electrical connections, if necessary, from terminals. Only
commission the valve using the preset manual adjusting knob or with
an actuator mounted in accordance with the relevant instructions.
