Data Sheet for Product

MVS661…N Modulating Refrigerant Valves Technical Instructions
for Ammonia (R717) and Safety Refrigerants Document Number 155-404
May 11, 2016
Siemens Industry, Inc. Page 11
Terminal assignment
for controller with
three-wire connection
Figure 5. Common Transformer.
Figure 6. Separate Transformer.
U
Valve position indication (only if required). 0 to 10 Vdc → 0 to 100% volumetric flow 100.
Twisted pairs. If the 24 Vac power supply and the 0/2 to 10 Vdc, 0/4 to 20 mA positioning signal are
routed separately, the 24 Vac line does not need to be twisted.
WARNING:
Piping must be connected to potential earth.
Valve Sizing and
Correction Factor
The applications and tables on the following pages are designed to help with selecting
the valves. To select the correct valve, the following data is required:
 Application
 Expansion (see Use of the MVS661…as an expansion valve)
 Hot-gas (see Use of the MVS661…as a hot-gas valve)
 Suction throttle (see Use of the MVS661…as a suction throttle valve)
 Refrigerant type
 Evaporating temperature t
0
°F (°C)
 Condensing temperature t
c
°F (°C)
 Refrigeration capacity Q
0
(kW)
To calculate the nominal capacity, use the following formula:
 k
vs
[m³/h] = Q
0
[kW] / K...* *K… for expansion = KE
for hot-gas = KH
for suction throttle = KS
 C
V
= 1.156 × kvs
 The theoretical C
V
(kv) value for the nominal refrigeration capacity of the plant
should not be less than 50% of the C
V
(kvs) value of the selected valve.
 For accurate valve sizing, Siemens Industry, Inc. recommends using the valve
selection program Refrigeration VASP.