Vaillant aroVAIR VA 2-3VW 050-100K – set with 3-way switching valve for cassette fan coils 5 and 10 kW

Product detailed description

Vaillant aroVAIR VA 2-3VW 050-100K – 3-way switching valve set for 5 and 10 kW cassette fan coils

VA 2-3VW 050-100K is a 3-way switching valve set from the Vaillant aroVAIR accessory range, structurally sized for the higher nominal water flow required by the larger power classes of the KN cassette series – models VA 2-050 KN (cooling capacity up to 5.86 kW) and VA 2-100 KN (cooling capacity up to 11.55 kW). Just like the smaller VA 2-3VW 035K set, this set addresses the situation when the fan coil is connected to a shared 2-pipe circuit, through which either warm water (heating season) or chilled water (cooling season) flows depending on the time of year, and the system needs to automatically switch between these two modes directly at the level of the individual fan coil unit without manual intervention in the piping.

Since the VA 2-050 KN and VA 2-100 KN models have significantly different nominal water flow rates (lower for the 5 kW version, higher for the more powerful 10 kW version with a flow rate of roughly around 6.9 m³/h), this 3-way valve set is structurally sized to handle the hydraulic demands of both power classes without excessive pressure loss or flow restriction, which with an undersized valve could reduce the actually achievable output of the fan coil.

Technical parameters and set contents

When is this set needed

Similarly to the smaller power class, the need for a 3-way valve here is also determined by the specific design of the system's hydraulic connection, not a universal requirement for every installation. The set is mainly used in configurations where multiple fan coils (for example a combination of VA 2-050 KN and VA 2-100 KN in different rooms) share a common piping distribution supplied from a single source, and it is necessary to ensure, during seasonal or operational switching between heating and cooling mode, that each unit receives water from the correct branch of the system without unwanted mixing of warm and chilled water. In larger installations (open-space offices, showrooms, commercial premises), where this power class is most commonly used, more complex hydraulic connections with multiple zones are more common than in small residential installations, which is why this set is in practice ordered fairly often together with the body of larger units.

Installation

The set is installed in the water piping distribution near the body of the fan coil unit, exactly at the position specified by the hydraulic design documentation. Given the higher nominal flow rate of the compatible units (especially the VA 2-100 KN model), it is important during installation to check the sizing of the connecting pipework and the pressure loss of the whole circuit, so that the valve does not cause excessive output restriction at full flow. The electrical connection of the actuator to the fan coil's control electronics or to the VA 2-AWC DK controller is carried out by a qualified technician as part of the overall electrical installation of the system, together with functional testing of correct switching in both operating modes.

Compatibility

This set covers both power classes of the larger cassette units in the KN series – the 5 kW VA 2-050 KN model and the 10 kW VA 2-100 KN model, similar to the shared cover panel code 8000018476 and the condensate collection tray code 8000022078 for the same pair of models. For the smaller 3.5 kW power class (VA 2-035 KN model), a separate, smaller set with code 8000029837 (VA 2-3VW 035K) is intended, which does not handle as high a flow rate as this larger version. When completing your order, it is therefore necessary to select the set that exactly matches the power class of the installed fan coil body.

Maintenance

Similarly to the smaller set, the main maintenance requirement is a regular annual check of switching function, tightness of the connecting joints and the condition of the actuator as part of the overall service of the heating/cooling system. In larger installations with higher water flow rates, increased attention should be paid to the quality and filtration of the circulating water, since impurities or deposits can more quickly affect the smoothness of the valve's mechanical switching at higher flow rates. We recommend following the heat/cold source manufacturer's instructions regarding water treatment for the entire system. Service inspection should be part of the regular annual inspection of the entire fan coil installation and the connected heat/cold source, similarly to other hydraulic components of the system.

Hydraulic considerations in larger installations

In larger buildings where more powerful cassette fan coils VA 2-050 KN and VA 2-100 KN are used – typically office spaces, showrooms, restaurants or retail premises – it is common for a single heat/cold source (for example a larger Vaillant aroTHERM plus heat pump in a higher power range) to supply multiple fan coil units at once through a branched piping system with multiple branches and zones. In such systems, hydraulic control of the flow between heating and cooling mode is significantly more complex than in a simple residential installation with one or two fan coils, and this is exactly where the use of a controlled 3-way valve at each unit becomes justified – it enables independent mode switching at the level of an individual zone or room without needing to switch the entire system at once from a central location.

When designing such larger systems, besides selecting the 3-way valve itself, the overall hydraulic balancing of the system is also considered (so that more powerful units such as the VA 2-100 KN do not draw a disproportionately large share of the flow at the expense of smaller units in the same system), sizing of circulation pumps with regard to the sum of the nominal flow rates of all connected appliances, and the choice of a suitable control strategy (for example central control via a building management system, or independent control of each zone by its own VA 2-AWC DK controller). These decisions should be made by a qualified heating and cooling design engineer based on the specific parameters of the building.

Advantages of automatic switching over manual adjustment

Without a controlled 3-way valve, the transition between the winter heating season and the summer cooling season with a shared piping distribution would require manual intervention – for example, adjusting manual shut-off valves at each fan coil separately, which with a larger number of units in the building is time-consuming and prone to error (for example, forgetting to adjust one of the units, which could cause that room to remain without the correct function for the whole season until the error is discovered). Automatic controlled switching using this set eliminates this risk – the system switches all connected units simultaneously based on a single signal from the controller or building management system, reducing the room for human error and simplifying the seasonal operation of the entire system.

Why order the VA 2-3VW 050-100K set

If your project involves a VA 2-050 KN or VA 2-100 KN cassette fan coil connected to a shared 2-pipe distribution with automatic seasonal or operational switching between heating and cooling, this set is an essential component designed specifically for the flow requirements of these more powerful units. By ordering the original set from the manufacturer, you ensure correct switching function even at the fan coil's full output and preserve the warranty conditions for the entire installation. We recommend including this set in your order together with the unit body, cover panel, VA 2-AWC DK controller and condensate collection tray, so that the entire installation is prepared from the start exactly according to the designed hydraulic scheme without the need to additionally order missing components after discovering that the project requires them.