Vaillant aroVAIR pro VA 3-035 WN - wall-mounted fan coil 3.8 kW

Product detailed description

Vaillant aroVAIR pro VA 3-035 WN is the mid-range output stage of the popular aroVAIR pro wall-mounted fan coil series, which combines heating and cooling of a space with quiet, energy-efficient operation connected to a Vaillant heat pump or condensing boiler. Compared with the smaller VA 3-025 WN model, it offers noticeably higher output - a cooling output of 3.81 kW and a heating output of up to 4.30 kW - while retaining the same philosophy of simple installation as a replacement for a classic radiator. The unit is thus suitable for somewhat larger or less well insulated rooms, or spaces with higher ceilings, where the smaller VA 3-025 WN model may no longer be sufficient.

Technical parameters of the VA 3-035 WN

The manufacturer states two heating output values for the VA 3-035 WN unit - 4.30 kW at a higher heating water temperature (typically when operated with a condensing boiler or at a system design temperature of around 55/45 °C) and 3.65 kW at a lower water temperature (the typical operating mode with a heat pump at a more economical temperature of approx. 35-45 °C, where the heat pump's COP efficiency is maximized). The same logic applies to cooling, where the stated total (sensible + latent) output is 3.81 kW and the sensible output (i.e. the part that actually lowers the air temperature without dehumidifying) is 3.30 kW - the difference between them corresponds to the portion of output used to condense moisture from the air.

Why choose the Vaillant aroVAIR pro WN wall-mounted fan coil

Wall-mounted WN fan coils are a solution for anyone who wants air-conditioning-like comfort in a flat or family house without having to deal with a refrigerant circuit, drilling the facade for an outdoor unit, or servicing a refrigerant circuit with a certified refrigerant technician. The fan coil works on water - the same water that already circulates in the house's heating system - so it only needs to be connected to an existing or newly built low-temperature heating circuit. Combined with a heat pump, a single outdoor device (the heat pump) can supply heat and cold to any number of indoor fan coil units, with each room able to have its own independently adjustable comfort. That is a fundamental difference from a classic split air-conditioning system, where every room needs its own indoor and outdoor unit, or a complex multi-split system.

Another advantage is the speed of temperature control. Underfloor or wall-based large-area heating has high thermal inertia - a change in the set temperature only takes effect after hours. Thanks to forced air through the heat-exchange surface, a fan coil reacts to a change in demand within minutes, which you will appreciate especially during the transitional spring and autumn periods, when it is cold outside in the morning and warm in the afternoon.

Who is the VA 3-035 WN intended for

The VA 3-035 WN model is a suitable choice for medium-sized living rooms - larger bedrooms, studies with a larger glazed area, dining rooms or smaller living rooms in flats and family houses. Thanks to its higher maximum air flow (up to 825 m3/h at high speed), the unit can more quickly equalize temperature differences after arriving home or during a sudden change in weather, while a lower fan speed with minimal noise is sufficient for normal operation.

Installation and connection

The wall-mounted VA 3-WN unit is mounted on the wall using the supplied mounting bracket, similarly to a classic panel radiator - the recommended height from the floor is approximately 15-20 cm, so that free air circulation is maintained both below and above the unit. The heating/cooling water supply and return pipes connect to the bottom or side of the casing (depending on the specific design), and the VA 3-WN model has an integrated 3-way switching valve directly in the unit body - meaning that no separate switching valve needs to be installed in the pipework when switching between heating and cooling mode, which simplifies and reduces the cost of installation, especially when several fan coils are connected to one manifold. A condensate drain hose is also included, which in cooling mode needs to be routed to a drain or collection vessel, since air humidity naturally condenses on the exchanger when air is cooled below the dew point.

Electrical supply is standard single-phase 230 V; the unit is controlled either by the supplied wireless remote control with an LCD display, or optionally by the Vaillant VA 1-WC WK wired wall controller, which is installed on the room wall and, besides control, also offers more accurate measurement of room temperature directly where people are present (instead of measuring at the air intake into the unit under the ceiling or by the wall).

Compatibility with heat sources

Fan coils in the aroVAIR pro range are designed primarily to work with Vaillant aroTHERM and aroTHERM plus (air-to-water) heat pumps, where thanks to their ability to operate with low heating water temperatures (typically 35-45 °C) they maintain a high heat pump COP while also enabling summer cooling by connecting to the heat pump's cold water circuit in reverse mode. The unit can equally well be connected to a Vaillant flexoTHERM (ground-to-water) heat pump, or used as a supplementary heating element in a system with a Vaillant ecoTEC or ecoCOMPACT condensing boiler - in this case the unit only operates in heating mode (cooling requires a cold water source). We recommend leaving the design of the number and output of fan coils, as well as the hydraulic connection (manifold, circulation pumps, and any mixing or switching valve), to an authorized designer or a Vaillant heat pump installation company, to ensure correct function and the manufacturer's warranty.

Output control and comfort

Like the other models in the VA 3-WN series, the VA 3-035 WN is also controlled by the supplied wireless remote control with an LCD display or the optional VA 1-WC WK wired controller. Automatic (Auto) mode itself evaluates whether heating, cooling or just ventilation is needed at any given moment, based on the set target temperature and the current room temperature. Three fan speed levels (MIN/MED/MAX) can be selected manually or left to the automatic control, which temporarily increases speed for a faster response when there is a larger deviation from the desired temperature, and then reduces it to a quieter, more comfortable operation.

Maintenance and care

Vaillant aroVAIR pro fan coil units have a replaceable/washable air filter built in behind the front grille, which captures dust and some allergens before they get inside the exchanger. It is recommended to check the filter and, if needed, clean it with a vacuum cleaner or rinse it with lukewarm water approximately once every 4-8 weeks during a season of intensive use (both heating and cooling), while a check once every 2-3 months is sufficient for normal operation. A clogged filter reduces air flow, increases noise and reduces unit output, so regular checking pays off. In cooling mode it is advisable to check the condensate drain's patency once a year (ideally before the start of the summer season) to prevent it from accumulating inside the unit. The exchanger itself and the fan normally require no servicing at all; it is only recommended to occasionally visually check the tightness of the hydraulic connections during a service inspection of the heating system.

Frequently asked questions

Summary - why the VA 3-035 WN

The Vaillant aroVAIR pro VA 3-035 WN offers a noticeable performance edge over the entry-level model in the series while retaining the same ease of installation, quiet DC inverter operation and integrated 3-way valve. It is a well-balanced choice for medium-sized rooms where you need fast and reliable control of thermal comfort throughout the year.

Typical deployment scenario

Imagine a new build with a Vaillant aroTHERM plus heat pump as the sole heat and cold source, where besides underfloor heating in the living areas, the investor wants to add a fast-reacting element also capable of summer cooling in a bedroom with larger glazing and in a study with computer equipment (i.e. with a higher internal heat load even in winter). It is precisely such rooms - with an area of roughly 18-28 m2 at a standard clear ceiling height and normal heat loss - that suit the VA 3-035 WN model. Thanks to its mid-range output within the VA 3-WN series, it can cover peak heat demand even on freezing days while effectively cooling the room on hot summer days, where heat from glazing or electronics would otherwise accumulate unpleasantly.

In apartment buildings, fan coils of this output are also often installed in south- or west-facing rooms, where solar gains in summer cause overheating despite good insulation of the building envelope - in that case the fan coil acts as supplementary, energy-efficient cooling without the need to build a separate air-conditioning system.

Acoustic comfort and DC inverter technology

The fan in the VA 3-035 WN unit uses a direct-current (DC) electronically commutated motor instead of older alternating-current (AC) technology. A DC motor allows smoother and more precise speed control at lower electrical energy consumption and, above all, lower noise for the same air flow compared with a classic AC fan switched only between a few fixed steps. As a result, the unit is quieter even at medium output than older generations of fan coils and is also suitable for quiet rooms, where the night setback (eco mode) is a further feature that automatically reduces speed and noise during sleep while maintaining the set comfort temperature.

Planning the number and placement of fan coils in a house

When designing a house with a heat pump and fan coils as a supplementary or primary heating/cooling element, the design is based on the heat loss (in winter) and heat load (in summer) of individual rooms, which are calculated separately for each space according to its orientation, glazed area, insulation thickness and internal heat sources (electronics, lighting, number of people). The VA 3-035 WN model, with its output of 3.81/4.30 kW, easily covers most common rooms in a family house with standard insulation; for very glazed rooms or rooms with high ceilings (e.g. mezzanine spaces), however, it is recommended to have the heat balance checked with a designer, or to consider the larger VA 3-045 WN model or an additional unit.

The advantage of a modular solution with several smaller fan coils over one large central unit is the ability to individually control the temperature in each room according to the current preferences of the occupants - for example, a cooler bedroom at night and a warmer living room in the evening, without the compromises of a single temperature for the whole house.

When combining several fan coils on a shared hydraulic circuit, it is advisable to supplement the system with balancing valves on the individual branches, so that water flow is evenly distributed among all connected units regardless of the pipe length to the given room. This wiring is typically designed and implemented by an authorized Vaillant heat pump installation company, which also registers the device and activates the manufacturer's warranty.