air conditioner is rattling

Why do you need a non-return valve for air conditioner drainage?

The efficiency and ease of use of a split system largely depends on its installation. if important nuances are provided at the stage of installing the air conditioner, then the owner will happily operate the device without bothering to solve unnecessary problems.

One of such important nuances is a check valve or, as it is also called, a siphon with a gate. This simple but important device can solve several problems at once.

In this article, we will tell you in detail why you need to install a non-return valve for air conditioners in the sewer, what is the principle of operation of this device and what should be considered when choosing it.

General information

valve for air conditioner

During the operation of the air conditioner, condensation forms in the system. It is collected in a drainage tray, from where it is then removed from the indoor unit via a drainage tube. In most cases, the drainage pipe goes directly to the street. You probably have noticed more than once how an air conditioner hangs on the facade of the house and water literally drips from it. Such situations often lead to conflicts with neighbors.

And such a» straight-line » method of condensate removal is prohibited by SNIPS. Water will flow not only on the neighbor’s balcony, but also on the facade of the house, as well as on the heads of passers-by. And if the air conditioner is installed in a country house, then over time the water is guaranteed to destroy the blind area. It’s not for nothing that they say that water sharpens a stone.

To solve this problem, the drainage pipe should be taken not to the street,but to the sewer. For these purposes, a non-return valve or, as it is often called, simply a siphon with a gate is used. This simple device is necessary for the unhindered removal of condensate, while neither fetid odors nor dangerous gas vapors will penetrate into the room.


There are several types of non-return valve for air conditioner drainage on the market. Let’s consider the main ones.

With a water seal

siphon with hydraulic seal

This is a standard type of siphon. It has a U-shaped shape and performs one single function-it protects against the penetration of toxic gases, while removing excess condensate into the sewer. Such a siphon has several key disadvantages.

Firstly, its dimensions are hardly compact: the height of the device can reach 30 centimeters! Secondly, the siphon does not always cope with blocking unpleasant odors. Thirdly, bacteria actively populate such a device due to the features of its design.

But a siphon with a hydraulic seal is inexpensive, easy to install and just as easily replaced with a new one if necessary.

With a valve that prevents the spread of odors

This is the most common variety that we recommend for installation. Such siphons are compact, equipped with a hydraulic lock, as well as a special drainage valve that does not let fetid odors into the room. Also, such devices are equipped with a camera in which dirt is collected. The siphon is convenient to maintain, which means that it will last longer.


anti-odor valve for air conditioner

A dry siphon is a so-called check valve for drainage. It is an elastic pipe that is almost always closed, and does not let odors and toxic gas into the room. When the condensate passes, the tube opens, removing excess water into the sewer, and then closes again.

In our opinion, it is the most technologically advanced and convenient valve of all the above. And here’s why:

  • The size of the dry siphon is significantly smaller than a conventional device with a hydraulic lock;

  • Siphon materials do not contribute to clogging;

  • Blocks unpleasant odors and toxic gas from the sewer;

  • Resistant to low temperature;

  • Has a high throughput due to the lack of a » knee»;

  • Can be mounted both vertically and horizontally.

Flush mounting

flush-mounted siphon

If aesthetics are important to you and you want to preserve the beauty of your repair, pay attention to flush-mounted siphons. They can have all the advantages of the previous types, but they are mounted in a niche in the wall. This is one of the best options for air conditioner drainage, since such a siphon is hidden from the eyes, but at the same time it regularly performs its function.

Flush-mounted siphons are a compact box with a size of 10×10 cm (there are other sizes, but this is the most common), mounted in a niche in the wall. It is equipped with a decorative door. The niche, of course, must be made in advance. There is a special container in the case for collecting dirt, it can be taken out and cleaned. To perform maintenance of the drain valve, it is necessary to remove the decorative cover.

This is a great solution for those who want to hide all communications, but at the same time worry about direct access to them. In the case of hidden installation, you will remove unnecessary technical devices from your eyes, but you will be able to open the door and service the siphon at any time.

Selection criteria

check valve for air conditioner

To choose the right siphon, take into account not only operational, but also technical characteristics.

Diameter. The siphon has an inlet pipe. Its diameter can not be selected by eye. Consider the diameter of the drainage tube. It should be the same as the diameter of the inlet pipe of the siphon.

Dimensions. One of the most important points that many people forget about. The siphon should fit into the space that you have allocated to it. If this is a hidden valve, then pay attention to the thickness of the wall so that the width of the siphon box does not turn out to be more than permissible.

Throughput capacity. Everything is simple here: the more powerful the air conditioner and the more often it is used, the higher the throughput of the siphon should be. The device must cope with the condensate flow, otherwise problems may arise. If in doubt, it is better to immediately take a siphon with increased throughput.

Tightness. A high-quality siphon should be equipped with special rubber seals. They will ensure the tightness of the structure. Otherwise, water or unpleasant odors can enter the room.

Price. Cheap is rarely of high quality. It is not necessary to save either on the siphon or on other components for the air conditioner. Also, you do not need to save on installers. After all, the efficiency of the siphon and the air conditioner as a whole largely depends on the quality of installation.


In order not to disturb neighbors and passers-by with condensate dripping from a height, take care of installing a drainage valve, it is also called a siphon. A check valve for air conditioners in the sewer will remove excess water into the drain, saving you from unnecessary problems.

When choosing a siphon, pay attention to its technical and operational characteristics. Any other questions? Ask them in the comments below. Well, if you have previously purchased or installed a siphon with a shutter, share your experience. It will be useful for many readers of our site. We wish you good luck!

Добавить комментарий

Ваш адрес email не будет опубликован. Обязательные поля помечены *