Siemens VPF44 / VPF54 Flanged Pressure Independent Control Valve DN 50-200

Overview

The Siemens VPF44 is the flanged pressure independent control valve (PICV) of the Siemens Acvatix range, built for the larger water circuits that serve air handling units, heat exchangers, district heating substations and plant room headers. It combines three functions in one cast iron body: a control valve, an adjustable flow presetting and an integrated differential pressure controller. The current range, published by Siemens Smart Infrastructure in data sheet A6V14362310, covers DN 50 to DN 150 as VPF44 (PN 16) and VPF54 (PN 25), and DN 200 as VPF43 (PN 16) and VPF53 (PN 25), with nominal flows from 15 to 280 m3/h.

Seven Star LLC supplies the Siemens VPF44 and its PN 25 sister VPF54 to consultants, MEP contractors and facility teams across Oman and the GCC, together with the matching SAX, SAV and SQV electromotoric actuators. Our engineers in Muscat help translate a coil or heat exchanger schedule into the right flow variant and dial setting, and prepare the submittal package from the manufacturer documentation.

Operating Principle

Water enters the Siemens VPF44 through inlet port A, passes the seat with its variable presetting opening and then the control valve, which is positioned by the actuator. The built-in differential pressure regulator holds the pressure difference across the control path constant. Because that pressure difference does not change when the pump speed or the load on neighbouring branches changes, the valve keeps full authority, and each stroke position corresponds to a defined flow. When the actuator drives the valve fully open, the flow is limited to the value set on the dial, so the valve also acts as an automatic balancing device. The valve characteristic is linear to VDI/VDE 2173, and the SAX61P, SAV61P and SQV91P actuators can be switched to a logarithmic characteristic for coil applications.

The rangeability of the Siemens VPF44 is 1:100. Average flow accuracy is plus or minus 10 percent from the minimum differential pressure up to 70 kPa on DN 50 to 80 and up to 105 kPa on DN 100 to 150, and plus or minus 5 percent above those values up to the maximum of 800 kPa. The VPF44 and VPF54 have three pressure test points: p1 at the inlet, p2 at the outlet of the control valve and p3 at the outlet port. Measuring p1 to p2 gives the flow, and measuring p1 to p3 confirms that enough differential pressure is available, which is the basis for setting a variable speed pump to the lowest safe head.

Engineering Design of the Siemens VPF44

On the PN 16 Siemens VPF44 versions DN 50 to 100 the body is grey cast iron GJL-250; PN 25 versions and all DN 125 to 200 valves use nodular cast iron GJS-400-18RT. The stem and spring are stainless steel, the sleeve is brass, the regulator is stainless steel and the seals are EPDM. Flanges follow ISO 7005-2, and the pressure test points have a G 1/4 inch connection for 2 mm by 40 mm measuring tips. Nominal stroke is 20 mm on DN 50 to 80, 40 mm on DN 100 and 125, and 43 mm on DN 150 and 200. Medium temperature is 1 to 120 degrees C for DN 50 to 150 and 1 to 110 degrees C for DN 200, and the leakage rate is Class IV to EN 1349.

The presetting scale of the Siemens VPF44 is symmetric, so identical dial positions give identical flow rates, and Siemens recommends mounting the actuator before presetting. The differential pressure regulator (DPR) of the VPF44 and VPF54 can be exchanged as a spare assembly, ALR series, which allows service without removing the valve body from the line. For accurate flow measurement Siemens advises 5 x DN of straight pipe upstream and 10 x DN downstream, and a strainer upstream of the valve. To keep noise low, the differential pressure across the valve should not exceed 150 kPa in normal operation.

Key Features

The main engineering advantages of the Siemens VPF44 and VPF54 family are:

• Combined control valve, flow presetting and differential pressure controller in one flanged body from DN 50 to DN 200.
• Standard and high flow variants per size, from 15 m3/h (DN 50) up to 280 m3/h (DN 200) nominal flow.
• Maximum differential pressure of 800 kPa across the control path, with close-off of 800 kPa with the listed actuators.
• Three P/T test points on VPF44 and VPF54 for flow verification and pump optimisation with the ALE10 electronic manometer.
• Rangeability of 1:100 and linear characteristic, switchable to logarithmic on SAX61P, SAV61P and SQV91P actuators.
• Exchangeable differential pressure regulator assembly for easier maintenance on DN 50 to DN 100.
• Actuator options with 3-position, DC 0 to 10 V, 4 to 20 mA or Modbus RTU control, and SQV91P versions with spring return.
• PN 16 grey or nodular cast iron and PN 25 nodular cast iron bodies with EPDM seals for chilled and hot water.

Industrial Applications

Large coils are where hydronic imbalance costs the most, and this is the duty the Siemens VPF44 was designed for. An air handling unit coil that receives 20 percent more chilled water than designed lowers the return temperature for the whole plant and forces extra chillers and pumps online. Fitting the Siemens VPF44 at each AHU, fresh air unit and plate heat exchanger keeps those loads at their design flow at every operating point, so variable speed pumps can follow demand while chillers run at the delta-T they were selected for. Typical sites in Oman include hospital central plants, airport terminals, shopping malls, hotel back-of-house plant rooms and district cooling energy transfer stations in Muscat, Duqm and Salalah.

Where the Siemens VPF44 PN 16 rating is not enough, the PN 25 VPF54 versions are suited to high-rise towers and district cooling networks where static head pushes working pressure above PN 16. Seven Star LLC supplies the Siemens VPF44 and VPF54 with SAX, SAV or SQV actuators, ALE10 manometers and P/T accessories, and supports contractors in the Sohar and Salalah free zones and across the GCC with selection, flow setting tables and documentation.

Technical Specifications

The Siemens VPF44 data below is taken from the Siemens VPF43/VPF44/VPF53/VPF54 data sheet:

How to Order

For a quotation on the Siemens VPF44 or VPF54, or for help choosing between Siemens VPF44 flow variants, send Seven Star LLC your valve schedule or a formal RFQ with flow, size and pressure class. Our instrumentation division in Muscat will confirm the flow variant, dial setting and actuator, provide the manufacturer data sheet available for download on this page, and coordinate quote supply on request with engineering support for Oman and the GCC. Related plant room equipment includes the Grundfos NB end-suction pump, the Danfoss VLT HVAC Drive FC 102 and the pFlow F5 ultrasonic flowmeter for chilled water.