Where Should a Check Valve be Installed?

Where Should a Check Valve be Installed?

Everyone has come across a situation when, being in their apartment, you can accurately determine which dish is being prepared by your neighbors, or, even worse, you smell tobacco. This occurs due to the ingress of foreign odors into the apartment through the ventilation duct during the reverse draft. To prevent this from happening, it is recommended to install a check valve for ventilation, which blocks the air flow in the opposite direction and helps to effectively remove the exhaust air from the room.

Installed check valves for different ventilation systems

Regardless of the type of ventilation, be it a natural supply and exhaust system or a mechanical system, the reverse draft is possible in it.

For natural ventilation, where ventilation ducts are used, check valves are used, which are especially sensitive to changes in the direction of air masses. For high-quality air exchange, it is better to install a check valve for ventilation simultaneously with the installation of ventilation ducts.

Installation of a non-return valve for ventilation in an apartment, where natural air circulation is carried out, is carried out in the walls between rooms. Usually, holes in the walls of an apartment are made near the doors and check valve grids are installed in them, which control the air flow.

Supply ventilation, the design of which consists of an air duct built into the outer wall, equipped with a grate for air intake from the street side. The filter cleans the outside air, and the check valve device regulates the supply air volume and helps to maintain the room temperature. At the same time, the installation of a check valve for supply ventilation makes it possible not to resort to additional ventilation of the rooms where plastic windows are installed, the air exchange will be sufficient.

where should a check valve be installed
Galvanized steel round check valve

Using a check valve in the kitchen and bathroom

The installation of a check valve for ventilation in the kitchen allows you to block, even when the hood is off, the flow of foreign odors with a reverse draft, but at the same time it does not prevent the exhaust air from the kitchen from being removed into the ventilation channel.

In order for ventilation to continue to work, the air ducts are equipped with ventilation grilles with a check valve for natural ventilation with openings through which the exhaust air is removed without the use of an exhaust hood. Recently, the demand has been for an exhaust hood with the removal of polluted air directly to the street. On the outside, the air duct is equipped with an exhaust ventilation check valve, which does not allow cold outside air to enter the room.

In the bathroom, mold and persistent odor of dampness are common. This is due to ineffective ventilation. The premise of a bathroom, first of all, needs high-quality removal of moist air and prevention of odors from other apartments. And given that the bathroom can be used by neighbors for smoking, with poor air exchange, tobacco smoke can enter through the ventilation shaft and into your bathroom, and therefore into the apartment. Installing a check valve for ventilation in the bathroom will solve the problem of foreign odors getting there.

Check valve for ventilation: device and classification of mechanisms

Let’s take a look at how the reverse ventilation valves work. The design of the ventilation check valve is quite simple: the valve blades are located on the same axis so that air can flow in only one direction. If the direction of flow changes, the valve closes. In addition to the function of blocking the reverse flow, the valve can be used to regulate the supply air volume by changing the cross-section of the air duct.

Air check valves for ventilation are distinguished by the following characteristics:

  • material for manufacturing – valves made of plastic or galvanized steel are used in various air ducts;
  • by design – a lattice, butterfly, petal, or membrane. In the device of the grill with a check valve for ventilation, louvers are provided that open under the pressure of air only in one direction, which eliminates the reverse flow. Such grilles with a non-return valve can have various shapes and designs and are installed at the inlet or outlet of the ventilation duct. The butterfly valve is a device that resembles a butterfly made of two plates held together by a spring. The diaphragm check valve is a thin flap that deflects even with a slight airflow and sticks to the ventilation grill when the flow changes direction. It is used, as a rule, with natural ventilation. The flap check valve is similar in principle to the diaphragm valve, but it is manufactured in the form of a rigid flap fixed on an axis,
  • in shape – rectangular or round. They are chosen depending on the shape and size of the duct section, where the check valve will be installed. Round valves for domestic needs are produced with a diameter of 100 mm, 120 mm, 125 mm, 150 mm, and above. Check valves used in industrial ventilation systems have diameters from 150 mm to 1000 mm.
External ventilation grill with non-return valve
Fan with integrated butterfly check valve
  • control method – valves according to their device are manual and electric. The manual ventilation check valve is manually adjustable by a lever or slide. The electric valve functions in conjunction with other supply and exhaust ventilation devices and automatically regulates the air flow;
  • installation method – the device can be mounted vertically or horizontally, depending on the design of the air ducts;
  • throughput – the volume of air passing through the valve per unit of time can be different.

What to be guided by when choosing a check valve

To decide which check valves for ventilation are better, you need to have an idea of ​​the main selection criteria:

  • the device should work even with small air movement, which is typical for natural ventilation. The thrust force with such air exchange is small, therefore, for effective air exchange, it is better to install an exhaust fan complete with a ventilation grill and a non-return valve;

Important! It should be understood that if the check valve model is incorrectly selected, air exchange in the room may deteriorate, up to a complete cessation.

  • the parameters of the check valve must correspond to the characteristics of the selected fan: for example, if the valve is 150 mm in diameter, then the fan must be of the same diameter. The fan power must be sufficient for the air flow to be created to open the valve petals;
  • environmental conditions. Some check valve devices are not capable of operating at low temperatures. Therefore, they are only mounted indoors;
  • features of the ventilation system. If the air duct of the system has a rectangular shape, then for ease of installation, a check valve is provided for ventilation of a rectangular cross-section. Dimensions are also selected taking into account the cross-section of the box. For domestic needs, air ducts and check valves for ventilation of 100 mm are more often used.
where should a check valve be installed
Rectangular plastic duct element with built-in petal check valve

Helpful advice! To be sure of the quality and compliance of the device with the characteristics, it is necessary to purchase check valves from reputable manufacturers.

Diy installation of a check valve for ventilation

To properly install the device with your own hands, first of all, you need to determine what place the check valve will take on the ventilation circuit.

A ventilation grill with a check valve is installed at the inlet or outlet of the ventilation duct. Such an installation is very simple to do with your own hands: the ventilation grille is fastened as tightly as possible to the wall with self-tapping screws or with the help of “liquid nails”, completely closing the air duct opening.

where should a check valve be installed
Installing a ventilation grill with a non-return valve is easy enough

If the check valve is installed in the ventilation shaft behind the fan, the fan is dismantled first. Then a valve is inserted into the vent hole and markings are applied to secure the device. After pulling out the case, holes for fastening are drilled in the marked places. After that, the body is installed in the channel and through the holes made, the places for fastening are planned already on the concrete wall itself. With the help of a bolt, holes are made at the designated places, into which the dowels will then be hammered. Then the valve is mounted in the ventilation duct.

Helpful advice! If, when installing the check valve with your own hands, there are gaps between the wall of the ventilation shaft and the body of the device, they are filled with silicone sealant.

After installing the check valve, the fan is mounted in its place. If installed correctly, the check valve will prevent the return air from entering the room.

The ventilation check valve is a simple but effective device that contributes to high-quality ventilation and the creation of a healthy indoor climate.


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