Control valves
Control valves
Control valves are essential for precise control of the flow and temperature of the heat transfer medium or refrigerant in industrial and commercial HVAC systems. We offer top-quality 2-way and 3-way valves suited to heat substations, refrigeration systems and complex process applications.
Models and manufacturers
In our range you will find equipment from the most reliable manufacturers, adapted to different system requirements:
- Danfoss:
- VS2 and VM2: 2-way threaded flow control valves. Important: only the valve body is sold, WITHOUT the actuator (AMV/AME actuators are ordered separately).
- VRB3, VRG3: 3-way threaded valves for mixing flows.
- VF2 (2-way flanged) and VF3 (3-way flanged): DN25-DN150 range, ideal for industry and large heat substations.
- Siemens:
- VVG44: a precise-control 2-way threaded valve (DN15-DN50 range). Its 3-way version for mixing flows is the VXG44.
- VVG549: a valve adapted to smaller flows (DN15-DN25 range).
- VVF series: flanged control valves for larger diameters (replace threaded models in large systems).
- Honeywell: popular compact V5825B valves.
How to select a control valve correctly?
Choosing the right valve determines the longevity and energy efficiency of the whole system. Pay attention to these criteria:
- Kv value and Authority β: These are the most important hydraulic calculation indicators. Authority is calculated by the formula: β = Δp_valve_100% / Δp_total_circuit_100%. The optimal value is β > 0.3. If the authority is lower, control becomes non-linear (close to the ON/OFF principle) and system efficiency is poorer.
- Characteristic types: EQM (equal percentage) - the HVAC standard, for smooth control of heat exchangers; Linear - for specific circuits and steam; Quick opening - suited only to ON/OFF shut-off functions.
- Materials and medium compatibility: For smaller DN (threaded valves) bronze or brass is used, for large flanged ones - cast iron. Stainless steel is chosen for aggressive media. The bodies are suited to working with district heating water, glycol solutions (up to 50%) and steam.
- Actuator selection: Control valves are sold as separate components. Electric actuators are selected SEPARATELY, taking into account the valve stroke, the pressure drop capability and the control signal.
- PN class: Pay attention to the maximum working pressure (e.g. PN16 or PN25) that matches your system parameters.
The PICV (dynamic control) alternative
In systems with constantly changing pressure differences, traditional valves are increasingly being replaced by PICVs (pressure-independent control valves). Innovative models such as the Danfoss AB-QM or IMI TA-COMPACT-P perform both smooth control and dynamic balancing functions, eliminating the influence of pressure fluctuations. You will find these solutions in the balancing valves category.
Frequently asked questions (FAQ)
- Is the Danfoss VS2 valve supplied together with an actuator?
No, the VS2 is only the valve body WITHOUT an actuator. To control it automatically, an AMV or AME series actuator must be purchased separately. - When should I choose a 2-way and when a 3-way valve?
2-way valves (e.g. VM2, VF2) are used for throttling and shutting off flow, while 3-way valves (e.g. VRB3, VRG3, VF3, VXG44) are intended for mixing or diverting flows in heating and cooling units. - What are the consequences of selecting a valve with β < 0.3?
The valve becomes "oversized" for the system. As soon as it opens, too much flow passes, so control becomes non-linear (it operates on an ON/OFF principle). This leads to large temperature fluctuations, excessive actuator work and faster wear of all the equipment.
Professional flow control and precise hydraulic balancing are essential conditions for the smooth and efficient operation of engineering systems. For our engineers, assembling heating automation is an area in which long experience has been accumulated. In doubt about the valve model, size or a suitable actuator? Contact our team or learn more by reading our HVAC articles.