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How to install a check valve on water: features and types of devices

For stable operation of the heating system and plumbing, it is imperative to install a check valve on the water. This equipment is referred to as shutoff valves, its task is to let the water flow in only one direction. This function enables a wide use of this device, especially for self-priming pumps and for the installation of autonomous water systems.

Sometimes a check valve performs protective functions against a variety of unplanned malfunctions and expensive leak repairs. In this article, we will consider in detail the features of the selection and installation of this unsurpassed device, as well as the question of how they are operated.

Device and principle of operation

Answering the question why a check valve is needed, it is worth saying that this device does not allow the water raised by the pump to return back to the well or well. Another advantage of using this valve is that you do not have to wait for the liquid to displace the air in the hose. If the hose has already been filled with water, the flow will start immediately.

What elements does the water check valve device include:

a collapsible metal case, which consists of two parts, each of which has a thread;
metal or plastic shutter with gasket;
spring designed to support the shutter.

Valve operation is not difficult. The principle of operation of the check valve for water for the pump is as follows: after the water stops flowing from the pump into the pipeline or hose, the valve is pressed by a spring and is in the closed position. When there is enough water pressure in front of the valve to depress the spring, the valve opens allowing water to flow into the pipeline.

When the pump is turned off, the water pressure drops, the valve is again pressed by the spring and becomes in the closed position. In addition to the spring, water pressure is created on the valve from the side of the pipeline, preventing it from opening. The most popular type of check valve is for domestic use.

Important: all valves work according to this principle, regardless of whether they are used with or without a pump on the pipeline.

Types of check valves

Check valves can differ from each other in the material from which they are made, in size, design and installation features. Let's try to sort and classify them according to the given distinctive features.

By type of locking element:

lifting type - in a device of this type of design, the shutter moves up and down. During the flow of water from the pump, the valve takes the open position, when the pressure in the pipeline drops, the valve closes again under the action of the spring;
rotary type - the shutter in the valve with such a device looks like a flap, which opens during the movement of water and closes again with the help of a return spring when the pump is turned off;
ball type - in this type of valve, the valve looks like a ball blocking the passage. The ball is supported by a spring. With water pressure, the ball rises and shifts, passing water into the line;
wafer type - it can be double-leaf and disk. The bicuspid valve has a shutter consisting of two wings that fold when water passes and close when it is absent. The disc type check valve in its design has a disc valve capable of moving along its own axis under the action of a spring fixed on it.

Domestic water valves most often have a lift-type design where the spring can be replaced. Since it is her failure that is the main cause of valve malfunction.

According to the material of manufacture:

made of brass - a reliable material resistant to corrosion, which is quite durable and unpretentious in maintenance. It is considered an ideal material in domestic use;
cast iron is a rather rarely used material due to its poor resistance to corrosion and gradual fouling. Valves made of cast iron are used on large diameter pipelines. In domestic use, valves made of this material are not found;
stainless steel - valves made of this material have practically no drawbacks. They are resistant to corrosion and aggressive substances, strong and durable. The only drawback, perhaps, is the high price, but the quality of the product corresponds to the price.

Most often, the components of the check valve are made of different materials. For example, the body can be made of brass or stainless steel, usually the shutter is made of plastic, while the spring is made of ordinary or stainless steel. Therefore, at the time of purchase, it is recommended to be interested in what materials the valve parts are made of.

Tip: for domestic needs, it is better to opt for a brass product due to their fairly long service life and relatively low price.

Mounting method:

coupling fasteners. Most models of check valves are attached in this way. The mount consists of two threaded transitions. Their diameter is very different, depending on the diameter of the pipeline;
flange mounts. As the name implies, fastening to the pipeline is carried out using flanges. Most often, this type of fastening is used on valves made of cast iron, which are operated on pipelines of large diameters;
flange fasteners. With this mounting, the valves are fixed between two flanges, which are tightened with bolts. Valves with this type of mounting are also used mainly on large diameter pipelines.

To size:

standard valves. Are applied on the most part of pipelines;
miniature products, mounted inside the water meters. They are used when there is not enough space on the pipeline for mounting a standard check valve;
small valves mounted at the outlet of water meters;
cast iron valves of large dimensions, mounted on industrial or public pipelines.

Where is this device installed?

The installation of a check valve for water is done in the following places:

at the outlet of a submersible pump located in a well or well. After the pump stops working, the water will not come back;
at the end of the suction pipe of a surface pump or pumping station lowered into the water. After the pump unit is turned off, the water will remain in the nozzle;
at the outlet of the cold pipeline to the boiler. In this case, in the absence of water in the cold pipeline, there will be no reverse outflow of water from the boiler;
on different types of pipelines, especially when hot and cold pipelines are used simultaneously. Due to the pressure difference in the pipelines, hot water may be forced into the pipeline with cold water or, conversely, through the mixer. A valve mounted on each of the pipelines separately will prevent its backflow;
in autonomous heating systems, when there are several separate circuits with different coolant pressures. In this case, a separate pump is installed for each circuit. If the pumps are of different capacities, it may happen that a more powerful device can push the coolant into the adjacent circuit, which supplies the unit with a lower power. This is completely unacceptable, so the check valve is a mandatory part in such a system;
on water meters, in order to prevent the movement of water in the opposite direction;
in the sewer to prevent backflow of sewage.

Correctly installing a check valve on the water yourself is quite simple; to carry out this operation, it is enough to have the right tool and have minimal plumbing skills.

How to choose a valve for home piping

When purchasing a protective device for installation on a pipeline, several features must be taken into account, then the device will delight the owner with its technical features. We suggest you consider a few simple rules.

Before purchasing, carefully study the design of the connecting elements of the device. It is very important that the diameters of the pipeline and the check valve match. In current domestic conditions, most people prefer to use coupling options, since most of the plumbing systems are assembled in this connection method.
Analyze the principle of operation of the check valve. If you do not have enough knowledge, consult the seller, or refer to the documentation if the product is branded. If you find any malfunctions or violations, it is better to refuse the purchase.
If you need to purchase a ball, flange or wafer mechanism for a pump or other technical needs, be sure to compare their capabilities with the characteristics of the environment in which they will work.
The material from which the structure is made should be selected based on the technical characteristics of the water pipe: plastic is suitable for polypropylene structures. If the check valve must be installed on a hot pipeline, the best option would be to choose a device made of durable metal, since most propylene designs are not resistant to high temperatures.
Brass products are an ideal alternative to all fragile structures. Products made of this material are well protected from various temperature and mechanical deformations; moreover, most of the designs have a ball-type action.

Attention! All protection devices against water hammer in the pipeline must be purchased wisely, when choosing, taking into account a number of functional features, and not just the selection rules.

Installation in the main line

The installation of a check valve for water in the main pipeline in the house is carried out after the pump (if any) and after the water meter. It should be noted that the principle of installation largely depends on the type of design you have chosen.

For coupling metal options, you can use welding or threaded connections. Both options are quite reliable in fixation. Most experts do not mark these installations as highly reliable, but, nevertheless, they are very functional.
If they decided to install an interflange mechanism, a technology is provided for fixing it in the pipeline between two plates. It is worth noting that the plates must be welded to the pipes separately, the same installation method is practiced for the pump, but all fastenings must be made strictly after the water meter.
A ball check valve is a type of flanged check valve that operates with a ball valve. Its fastening should be carried out only in suitable conditions, in addition, it is very important to observe the working arrangement of the water check valve.

The main rule of installation is to screw the valve in the right direction. In order to facilitate this task, an arrow is applied to the body of the device, which shows the direction of water movement through the valve.

We examined the purposes for which a water valve is needed, its principle of operation, and analyzed the varieties and features of this type of valves. The operation of these devices is able to prevent emergency situations in heating and plumbing systems, and in addition to simplify the operation of pumping stations and water pumps. Such plumbing is indispensable and is always in demand.