User Manual
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Siemens 2-Port and 3-Port Zone Valves, PN 16 / 20 CE1N4867en
Building Technologies For Asia Pacific Use Only 02.10.2008
Type summary
Valves Actuator
k
vs
p
s
p
max
2-port 3-port DN Connection
[m
3
/h] [kPa] [kPa]
Positioning
force
Control
signal
MVI421.15 MXI421.15 15 Rp ½“ 2.0
MVI421.20 MXI421.20 20 Rp ¾“ 3.5 300 300
2)
200 N
2-position
MVI421.25 MXI421.25
1)
25 Rp 1“ 5.0
1)
3-port valve with tight bypass order separately: VXI46.25T with SFA… electromotoric
actuator, for details see datasheet N4842
2)
Where p
max
is above 100 kPa, there is an increased risk of noise and erosion on the seat
and plug
k
vs
= Nominal flow rate of cold water (5 to 30 °C) through the fully open valve (H
100
), by a differential
pressure of 100 kPa (1 bar)
p
s
= Maximum permissible differential pressure at which the motorized valve will close securely
against the pressure (close off pressure)
p
max
= Maximum permissible differential pressure across the valve's control path, valid for the entire
actuating range of the motorized valve
Type Designation Switching point Contact rating
ASC2.1/18 Auxiliary switch on / off At approx. 50 % stroke Max. AC 250 V, 3 (2) A
Equipment combinations
Type Thermostats compatible to MVI421… / MXI421…
RAA.. RAA10; RAA20; RAB30..; RAA40
RAB.. RAB10; RAB10.1; RAB20; RAB20.1; RAB30; RAB30.1; RAB40.1
RCC.. RCC10; RCC20; RCC20.1; RCC30
RDX.. RDX42.2
RDF.. RDF10; RDF10.1; RDF10.2; RDF20; RDF30, RDF110, RDF210
RDE.. RDE10; RDE10.1; RDE20.1
RDD.. RDD10; RDD10.1
RCU.. RCU10; RCU10.1
When ordering, please specify the quantity, product name and type code.
10 3-port zone valves, type MXI421.25
The valves and actuators are packed together; the auxiliary switches will be packed
separate.
Technical and mechanical design
The zone valves are closed when de-energised. An on/off controller (thermostat) is
required to drive the motorised valve actuators. If the temperature of the medium
deviates from the set point, the controller delivers a control signal that drives the
actuators, causing the valve to open. When the temperature of the medium reaches the
set point the control signal is cut off and the valve closes.
The valve is opened electrically by the actuator and closed by spring force.
The actuator incorporates a synchronous motor, a gear mechanism and a return spring.
The electric motor is overload-resistant and anti-locking, so that continuous operation is
possible. The maximum stroke is limited mechanically. The closing motion, by contrast,
includes an overrun for the gear mechanism. This protects the gear mechanism from
mechanical shock and increases service life.
Accessories
Thermostats
Ordering
Example
Delivery