Vaillant recoVAIR air flow limiter (24 pcs)

Product detailed description

Airflow restrictor, 24 pcs (Vaillant recoVAIR, code 0020180827)

A control element for fine-tuning and balancing the airflow between individual 75/62 mm duct branches connected to the manifold or collector of the recoVAIR system.

The airflow restrictor is a small but, in terms of the correct functioning of the entire controlled ventilation system with heat recovery, key control element from the Vaillant recoVAIR range. It is used for fine-tuning (balancing) the amount of air flowing through individual 75/62 mm diameter duct branches connected to a common air manifold or collector. The package contains 24 pieces, which corresponds to the typical number of outlet ports on larger modular and low-profile manifolds used in the recoVAIR system (these are manufactured in configurations with 8, 12, or 17 outlets, and larger installations with multiple manifolds in one house will consume a correspondingly higher number of these restrictors).

Overview of main parameters

Purpose: control insert for 75/62 mm ducting; package: 24 pieces; material: durable plastic with a stable constriction diameter; operating principle: targeted increase of local resistance in a branch in order to equalize airflow between branches of different lengths and complexity; installation location: near the manifold or collector, on branches with excessive flow; need for professional adjustment: yes, using anemometer measurement when commissioning the system.

Why balancing the airflow between branches is necessary

Even though the entire ductwork is designed by an HVAC engineer to theoretically ensure the required airflow to each room, in a real building the individual branches differ in length, number of direction changes (elbows), and sometimes also in minor deviations from the design that arise during installation itself. These differences mean that, without additional regulation, shorter and straighter branches with lower resistance would "take" a disproportionately larger share of the air at the expense of longer or more complex branches with higher resistance, since air always seeks the path of least resistance. The result of an unbalanced system would be rooms with excessive airflow (and the associated noise and draught sensation) on one hand, and rooms with insufficient air exchange on the other – which is the exact opposite of what a properly designed and balanced controlled ventilation system is meant to achieve.

The airflow restrictor solves precisely this problem – it is inserted into the branch with lower resistance (i.e. where, without regulation, too much air would flow) and, through its design (a narrowed or partially covered cross-section), increases the local resistance of that branch to a level corresponding to the designed distribution of flows among all branches connected to the given manifold.

Design and operating principle

The restrictor has the shape of a ring or short insert, which is placed within the 75/62 mm duct run, typically near the manifold or directly into the socket of the adapter connecting the hose to the manifold. The internal diameter of the restrictor is narrowed by a precisely defined value compared to the standard free cross-section of the hose, corresponding to the specific setting required for that particular branch. An analogous principle is used by other control elements in the recoVAIR range intended for other types of connections – for example, the so-called "Volumenstromdrossel" (volume flow damper) for 125 mm diameter connections on both rectangular and round outlets, which works on the same principle of a targeted increase in local resistance in order to equalize flows between branches of different lengths and complexity.

Where and when the restrictor is installed

The restrictor is installed when commissioning the controlled ventilation system, as part of the so-called balancing (regulation) of the ductwork, which is carried out by a qualified technician after completing the installation of the entire duct system and before the final handover of the system to the client. The procedure involves the technician using an anemometer or other measuring instrument to measure the actual airflow at each outlet, comparing it with the design value, and, wherever the flow is higher than required, fitting a restrictor with a suitable degree of constriction to reduce the flow to the correct level. This process is usually repeated iteratively (balancing one branch may slightly affect the flows in other branches connected to the same manifold), so balancing the entire system may take several hours even for a medium-sized installation with dozens of outlets.

Why the package contains 24 pieces

The quantity of 24 pieces per package corresponds to the typical need for an installation with one or two larger manifolds (for example with 12 or 17 outlets), where in practice a restrictor is not fitted to absolutely every branch (some branches may already be sufficiently balanced due to their natural length and configuration without additional regulation). However, having a sufficient supply of pieces in one package allows the technician to experiment with various combinations and degrees of constriction on multiple branches at once during the balancing process, without worrying about running out of material mid-job. For larger installations with multiple manifolds, we recommend ordering a corresponding multiple of packages according to the total number of outlets in the project.

Consequences of incorrect or missing balancing

If the airflow balancing process is skipped or carried out carelessly, the consequences will become apparent already in the first weeks of the system's operation – in some rooms the air will flow noticeably stronger and louder than in others, which occupants often perceive as an unpleasant draught or disturbing noise, especially in bedrooms at night. At the same time, rooms with insufficient fresh air supply may show higher humidity or CO2 concentration than the design value, which is directly at odds with the main purpose of controlled ventilation – namely ensuring a healthy indoor climate evenly in all rooms of the house, not just in those with the lowest ductwork resistance.

Compatibility

The airflow restrictor is designed for the 75/62 mm duct system and is compatible with all manifolds, collectors, and adapters of this series in the Vaillant recoVAIR range. For systems with a different duct diameter (for example flat ducting 52 x 132 mm or larger DN 125 mm connections at the outlets themselves), the Vaillant range includes separate control elements with the appropriate dimensions and operating principle adapted to that type of connection.

Recommendations for technicians performing the balancing

During the balancing process, we recommend proceeding systematically – first measure the flows at all outlets connected to the given manifold in an unregulated state, then identify the branch (or branches) with the highest flow compared to the design value, and fit that branch with a restrictor of an appropriate degree of constriction. After each adjustment, it is advisable to re-measure the flows on all branches of the given manifold, since narrowing one branch will slightly increase the pressure (and therefore the flow) on the other, unrestricted branches. This iterative process is repeated until acceptable agreement is achieved between the measured and design flow values at all outlets connected to the given manifold.

Maintenance

Once correctly set during commissioning, the airflow restrictor requires no further regular maintenance. However, we recommend not adjusting its setting on your own without re-measuring the entire system, since a change in constriction on one branch also affects the flows on the other branches of that manifold. If ventilation requirements for a particular room change during the use of the house (for example, a change in the room's purpose or the addition of another source of moisture), we recommend calling in a professional technician to reassess and, if necessary, adjust the settings of the restrictors on the affected branches.

Frequently Asked Questions (FAQ)

Relation to the overall energy balance of the house

Correctly balancing the airflow between individual rooms is not just a matter of comfort but is also directly related to the overall energy balance of heating and cooling the house. If a room receives significantly more fresh air (cold in winter, warm in summer) than necessary, the heating or cooling system must expend more energy to compensate for this excess air, while another room with insufficient inflow may suffer from inadequate air exchange, with an associated increased risk of moisture condensation or accumulation of CO2 and other indoor air pollutants. Precise balancing using airflow restrictors therefore contributes not only to better comfort but also to lower heating and cooling operating costs compared to an unbalanced system, where some rooms receive a disproportionate amount of air at the expense of others.

Comparison with alternative regulation methods

In addition to this type of simple mechanical restrictor (with a fixed degree of constriction), the market also offers more sophisticated flow regulation solutions, such as motorized control dampers with electronic control, which can automatically change the flow according to current needs (for example, based on CO2 or humidity sensors in the given room). However, these advanced solutions are significantly more expensive and technically more demanding to install and maintain, which is why standard residential recoVAIR installations most commonly use precisely this simple and reliable mechanical restrictor, whose setting is done once during system commissioning and only occasionally reassessed when the use of individual rooms changes.

Who this product is intended for

The airflow restrictor is intended primarily for professional installation and service companies commissioning the Vaillant recoVAIR controlled ventilation system, specifically the process of balancing and regulating the flow between individual duct branches. It is an essential part of the equipment of every technician responsible for the correct functioning and handover of the completed system to the client in accordance with the designed airflow values for individual rooms.

Material and mechanical design

The restrictor is made of durable plastic that retains a precise constriction diameter even after years of operation (without deformation due to temperature or the pressure of flowing air) – this is crucial for the stability of the system's balancing over time, since any change in the shape or diameter of the restrictor could gradually disrupt the originally set distribution of flows between branches. The restrictor's design allows for easy insertion and removal from the duct run without the need to dismantle a larger part of the ductwork, which technicians appreciate during repeated adjustments to the settings throughout the balancing process.

Documenting the settings for future maintenance

We recommend that the installation or service company, after completing the system balancing process, record which specific branches were fitted with restrictors and with what degree of constriction, and possibly attach this documentation to the system handover protocol for the client. This record significantly facilitates any future interventions in the system – for example when the purpose of a room changes, when dealing with a complaint about uneven ventilation, or during a routine periodic inspection of the entire controlled ventilation system with heat recovery after several years of operation.

Summary and package contents

The package contains 24 pieces of the airflow restrictor for 75/62 mm ducting, designed to fine-tune (balance) the amount of air flowing through individual duct branches connected to the manifold or collector of the Vaillant recoVAIR system. This is a genuine control element supplied directly by the manufacturer Vaillant, essential for the correct functioning and even air exchange in all rooms of a house or apartment. When ordering, we recommend considering the number of packages needed based on the total number of branches and manifolds in the project, or consulting the exact quantity with the installation company responsible for commissioning the system, so that the technician has a sufficient reserve of material available throughout the balancing process and for any later corrections.