Siemens Building Technologies MVL661 Data Sheet

714

ACVATIX

Modulating refrigerant valves with magnetic actuator, PS45

Hermetically sealed, for safety refrigerants

MVL661..-..

Use

CE2N4714en

30.05.2011

• One valve type for expansion, hot-gas and suction throttle applications

• Hermetically sealed towards outside

• Selectable standard interface DC 0/2...10 V or DC 0/4...20 mA

• High resolution and control accuracy

• Precise positioning control and position feedback signal

• Short positioning time (< 1 s)

• Closed when deenergized

• Robust and maintenance-free

• Five valve sizes with k

The MVL661..-.. refrigerant valve is designed for modulating control of refrigerant circuits including chillers and heat pumps. It can be used in expansion, hot-gas and suction throttle applications as well as with all commonly used safety refrigerants (R22, R134a, R404A, R407C, R410A, R507, etc.) and R744 (CO inflammable refrigerants.

values from 0.25 to 12 m³/h

). Not suitable for

Building Technologies

Type summary

Type reference DN kvs k

reduced

Δp

max

Q0 E Q0 H Q0 D

[m3/h] [m3/h] [MPa] [kW] [kW] [kW]

MVL661.15-0.4 15

MVL661.15-1.0 15

MVL661.20-2.5 20

MVL661.25-6.3 25

MVL661.32-12 32

63% of kvs, refer to "kvs reduction" on page 4

MVL661.32-12.0 is only approved for suction throttle applications

Nominal flow rate of refrigerant through the fully open valve (H

0.40 47 9.2 1.7

0.25 29 5.7 1.0

1.0 117 23 4.2

0.63 74 14 2.6

2.5 293 57 10

2.5

1.6 187 37 6.6

6.3 737 144 26

0.2

468 92 17

) at a differential pressure of

100

100 kPa (1 bar) to VDI 2173

E Refrigeration capacity in expansion applications

H Refrigeration capacity in hot-gas bypass applications

D Refrigeration capacity in suction throttle applications and Δp = 0.5 bar

With R407C at t0 = 0 °C, tc = 40 °C

The pressure drop across evaporator and condenser is assumed to be 0.3 bar each, and 1.6 bar upstream of the evaporator (e.g. spider).

The capacities specified are based on superheating by 6 K and subcooling by 2 K.

The refrigeration capacity for various refrigerants and operating conditions can be calculated for the 3 types of application using the tables at the end of this data sheet. For accurate valve sizing, we recommend the valve selection program "Refrigeration VASP".

Ordering

Example:

Spare parts

Rev. no.

Functio

n / mechanical design

Features and benefits

Valve body and magnetic actuator form one integral unit and cannot be separated.

Product number Stock number Designation

MVL661.15-0.4 MVL661.15-0.4 Refrigerant valve 1

Quantity

If the valve’s electronics become faulty, the entire electronics housing must be replaced by spare part ASR61, supplied complete with mounting instructions (74 319 0270 0).

See table on page 17.

• 4 selectable standard signals for setpoint and measured value

• DIP switch to reduce the k

value to 63% of the nominal value

• Potentiometer for adjustment of minimum stroke for suction throttle applications

• Automatic stroke calibration

• Forced control input for “Valve closed” or “Valve fully open”

• LED for indicating the operating state

The MVL661..-.. can be driven by Siemens or third-party controllers that deliver a DC 0/2...10 V or DC 0/4...20 mA output signal. For optimum control performance, we recommend a 4-wire connection between controller and valve. When operating on DC voltage, a 4-wire connection is mandatory! The valve stroke is proportional to the control signal.

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Siemens Modulating refrigerant valves with magnetic actuator, PS45 CE2N4714en Building Technologies 30.05.2011

Operator controls and indicators in the electronics housing

G0 G Y UMZC

1 Connection terminals 2 LED for indication of operating state 3 Minimal stroke setting potentiometer Rv 4 Autocalibration

1234

5 DIL switches for mode control

Configuration of DIL switches

-reduction

Minimum stroke setting

Caution

4716Z15

Switch Function ON / OFF Description

Factory setting

Positioning signal Y

Positioning range Y and U

Position feedback U

Nominal flow rate k

ON Current [mA]

OFF Voltage [V]

ON DC 2…10 V, 4…20 mA

OFF DC 0…10 V, 0…20 mA

ON Current [mA]

OFF Voltage [V]

OFF

For k

63%

100%

reduction (DIL switch 4 in

position ON), the stroke is limited to 63% mechanical stroke. 63% of full stroke then corresponds to an input/output signal of 10 V. If, in addition, the stroke is limited to 80%, for example, the minimum stroke is 0.63 x 0.8 = 0.50 of full stroke.

100 %

80 %

Stroke

In the case of a suction throttle valve, it is

4716D01en

essential that a minimum stroke limit be maintained to ensure compressor cooling and efficient oil return. This can be achieved with a reinjection valve, a bypass line across the valve, or a guaranteed minimum opening of the valve. The

0 %

0 % 100 %

Y-i np ut

minimum stroke can be defined via the controller and control signal Y, or it can be set directly with potentiometer Rv.

The factory setting is zero (mechanical stop in counterclockwise direction, CCW). The minimum stroke can be set by turning the potentiometer clockwise (CW) to a maximum of 80% kvs.

Do not under any circumstances use potentiometer Rv to limit the stroke on expansion applications. It must be possible to close the valve fully.

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Siemens Modulating refrigerant valves with magnetic actuator, PS45 CE2N4714en Building Technologies 30.05.2011

Forced control input ZC

No function Fully open Closed

ZC – Function

Signal priority

Calibration

When is a calibration

required?

Indication of operating state

Connections Transfer

• ZC not connected

• Valve will follow the Y-signal

• Minimum stroke set-ting

function

with potentiometer Rv possible

• ZC connected to G

• Valve will fully open control

path A  AB

• ZC connected to G0

• Valve will close control path

A  AB

1. Forced control signal ZC

2. Signal input Y and/or minimum stroke setting with potentiometer Rv possible.

The printed circuit board of the MVL661..-.. has a slot to facilitate calibration.

01124

To calibrate, insert a screwdriver in the slot so that the contacts inside are connected. As a result, the valve will first be fully closed and then fully opened. Calibration matches the electronics to the valve mechanism. During calibration, the green LED flashes for about 10 seconds; refer to "Indication of operating state" (page 4).

MVL661..-.. refrigerant valves are supplied fully calibrated.

Execute a calibration after replacing the electronics, when the red LED is lit or flashing or when the valve is leaking (at seat).

LED Indication Function Remarks, troubleshooting

Green Lit

Flashing

Red Lit

Flashing

Both Dark

Control mode Automatic operation; everything o.k.

Calibration in progress

Calibration error

Internal error

Mains fault Check mains network (outside the frequency or

No power supply Electronics faulty

Wait until calibration is finished (green or red LED will be lit)

Recalibrate (operate button in opening 1x) Replace electronics module

voltage range)

Check mains network, check wiring Replace electronics module

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Siemens Modulating refrigerant valves with magnetic actuator, PS45 CE2N4714en Building Technologies 30.05.2011

Connection type

4-wire connection 3-wire connection

Sizing

Notes

Engineering notes

Always give preference to a 4-wire connection!

SNA P

Product number [VA] [W] [A] max. cable length L [m]

MVL661..-.. 22 12 1.6…4 A 65 110 160

MVL661..-.. 22 12 1.6…4 A 20 35 50

SNA = Nominal apparent power for selecting the transformer P

med

IF = Required slow fuse L = Max. cable length; with 4-wire connections, the max. permissible length of the separate 1.5 mm2

All information at AC 24 V

With 4 mm2 electrical wiring reduce wiring cross-section for connection inside valve to 2.5 mm2.

= Typical power consumption

copper positioning signal wire is 200 m

IF Wire cross-section [mm2]

MED

1.5 2.5 4.0 2)

For straightforward valve sizing, refer to the tables for the relevant application (from page 13). For accurate valve sizing, we recommend to make use of the valve sizing software "Refrigeration VASP", available from your local Siemens office.

The refrigeration capacity Q

is calculated by multiplying the mass flow by the specific

enthalpy differential found in the h, log p-chart for the relevant refrigerant. To help determine the refrigeration capacity more easily, a selection chart is provided for each application (page 9 and following). With direct or indirect hot-gas bypass applications, the enthalpy differential of Q

(the condenser capacity) must also be taken into account

when calculating the refrigeration capacity. If the evaporating and / or condensing temperatures are between the values shown in the tables, the refrigeration capacity can be determined with reasonable accuracy by linear interpolation (refer to the application examples on page 9 and following). At the operating conditions given in the tables, the permissible differential pressure

(25 bar) across the valve is within the admissible range for these valves.

Δp

max

If the evaporating temperature is raised by 1 K, the refrigeration capacity increases by about 3%. If, by contrast, subcooling is increased by 1 K, the refrigeration capacity increases by about 1 to 2% (this applies only to subcooling down to approximately 8 K).

Depending on the application, additional installation instructions may need to be observed and appropriate safety devices (e.g. pressostats, full motor protection, etc.) fitted.

Warning

To prevent damage to the seal inside the valve insert, the plant must be vented on the low-pressure side following a pressure test (valve port AB), or the valve must be fully open during the pressure test and during venting (power supply connected and positioning signal at maximum or forced opening by G → ZC).

Expansion application

To prevent formation of flash gas on expansion applications, the velocity of the refrigerant in the fluid pipe may not exceed 1 m/s. To assure this, the diameter of the fluid pipe must be greater than the nominal size of the valve, using reducing pieces for making the connections to the valve.

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Siemens Modulating refrigerant valves with magnetic actuator, PS45 CE2N4714en Building Technologies 30.05.2011

Engineering notes

1 = Evaporator 2 = Compressor 3 = Condenser 4 = Expansion valves

a) The differential pressure over reduction must be less than half the differential

pressure Δp

b) The inlet path between diameter reduction and expansion valve inlet

 Must straight for at least 600 mm  May not contain any valves

A filter / dryer must be mounted upstream of the expansion valve. The valve is not explosion-proof. It is not approved for use with ammonia (NH3, R717).

Mounting notes

The valve should be mounted and commissioned by qualified staff. The same applies to the replacement electronics and the configuration of the controller (e.g. SAPHIR or PolyCool).

• The refrigerant valves can be mounted in any orientation, but

90°

upright mounting is preferable.

• Arrange the pipework in such a way that the valve is not

located at a low point in the plant where oil can collect.

• The pipes should be fitted in such a way that the alignment

does not distort the valve connections. Fix the valve body so

4716Z16

00441

that that it cannot vibrate. Vibration can lead to burst connection pipes.

• Before soldering the pipes, ensure that the direction of flow

through the valve is correct.

• The pipes must be soldered with care. To avoid dirt and the

formation of scale (oxide), inert gas is recommended for soldering.

• The flame should be large enough to ensure that the junction

heats up quickly and the valve does not get too hot.

• The flame should be directed away from the valve.

• During soldering, cool the valve with a wet cloth, for example,

to ensure that it does not become too hot.

• Port B must be sealed off when a 2-port valve (AB  A) is

used.

• The valve body and the connected pipework should be

lagged.

• The actuator must not be lagged.

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Siemens Modulating refrigerant valves with magnetic actuator, PS45 CE2N4714en Building Technologies 30.05.2011

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