The efficiency of its operation, including the safety of people using the unit, depends on the correct manufacture of the piping of the boiler as a storage tank. The most important element of the control system for its operation is a safety valve for the boiler, mounted in the cold water channel and performing a protective function. Understanding where the check valve is installed on the water heater and how it is mounted is the primary task of owners of heating equipment.
Actuation principle
In the presence of an emergency valve in the cold water supply, it is possible to prevent the pressure of the liquid carrier from rising above the limit value. It is possible due to the expansion of the water entering the boiler and the increase in liquid in volume. Taking into account the fact that the boiler is a sealed device, there is nowhere for excess liquid to go, since another one is placed on the supply - a check valve. When heated, the pressure in the unit increases and reaches the limit. To prevent the tank from bursting completely, a pressure relief valve for boilers is needed.
A natural question arises: why install it when you can remove the check valve. The inadmissibility of this option is explained as follows:
- The pressure in the water supply system is not particularly stable.
- There are situations when hot water almost stops flowing from the tap - its pressure is too low.
- It is displaced into the supply channel of the water supply system, and the heating elements heating it are exposed and quickly burn out.
Burned-out heating elements are still half the trouble. It is much more dangerous when they heat up with a simultaneous rise in pressure in the system. The water that gets on them after heating evaporates with a sharp expansion effect, leading to rupture of the flask. Boiling water and steam will escape and can cause injury to users. The principle of operation, consisting in relieving excess pressure in the system, will avoid a serious accident.
Varieties of valves
By their mechanism of action, bypass valves are divided into the following types:
- spring;
- lever;
- magnetic spring;
- waste.
In the first samples of check valves on the boiler, the main working element is a spring, and in the second there is a lever that controls the state of the system in test mode. Models of the magnetic spring type are referred to as combined devices that combine the advantages of field and mechanical structures.
Depending on the type of locking mechanism, the following types of check valves are distinguished:
- lifting type;
- rotary and ball;
- interflanged.
The platter of the disc mechanism in the first models moves up and down. After the appearance of pressure in the forward direction, the shutter opens, and in the event of its disappearance or weakening, it closes due to the spring or its own weight.
The device operates to close and maintains the pressure also when the direction of movement of the fluid flow is changed.
The pivoting or non-returnable version is made in the form of a flap that pivots and opens under the pressure of fluid. Spring force is used to close it.
The ball design is understood as a mechanism in which the fluid flow is blocked by a ball pressed against the seat by a return spring.The pressure of the liquid in the other direction squeezes the ball in the opposite direction, opening the passage for it.
The wafer valve design is similar to a lift mechanism, but the poppet moves in the direction of flow. Its modification contains two doors folding towards each other. The two-leaf design, when open, has minimal resistance to fluid flow.
If the valves are classified according to the material from which they are made, the following versions are distinguished:
- Brass products characterized by reliability and durability. They are most often used in everyday life.
- Cast iron valves are very inexpensive devices that have one characteristic drawback. They are not protected from rust in any way and are installed only on pipe lines.
- Stainless mechanisms, which are high quality and reliable products with a high price.
It is advisable to use the latter samples only in particularly critical sections of pipelines.
According to the method of fixation on the working object, all water return valves are divided into the following types:
- Coupling mechanisms installed in a pipe break by means of two threaded couplings of the appropriate size. This variety is most common in everyday life, in some cases it is used in production.
- Flanged devices, where the valve mechanism is connected by means of specially designed connectors. They are most often used in combination with cast iron counterparts on large pipes.
- Isolation valves installed between two flanges that are pulled together for strength with through studs. This type is most often installed on the same main pipelines.
Installation locations
In domestic water supply and heating systems, there are many sections and runs where a safety valve can be mounted.
- On the branch to an apartment or a private house from a centralized hot water supply line (DHW).
- After the liquid flow meter, ensuring its protection against water hammer.
- At the inlet of a gas or electric water heater (boiler), which avoids the outflow of heated and expanded water into the line with cold water supply.
Protective elements are installed in places provided for by their design features and direct purpose.
DIY installation
The fuses are chosen according to the pressure for which the unit protected from emergency situations is designed (it is given in the passport). The choice is influenced by the volume of the tank declared in the characteristics, according to which the response limits are designed for 6, 7, 8 and 10 bar. Its installation is simple: a little FUM tape or oiled tow is wound on the thread, after which the product itself is screwed onto the working pipe. The device is screwed in by hand until it stops, and then two more turns with the key are made.
The procedure is as follows:
- The place for installing the adjustment device is determined. It is selected depending on what kind of water the valves are to be installed on the water heater - most often on the cold water supply.
- The presence of a ball valve is taken into account - it is needed to empty the tank before winter storage.
- The valve for the boiler is often placed on the side of a tee mounted directly on the inlet pipe.
A safety flap valve is screwed to it from below.
Testing
To check the serviceability of the valve product, an excess pressure relief lever is provided. With the heater turned off, raise the lever several times to lower these excess. After the water stops dripping, wait until heating starts. If the fluid continues to flow, the spring mechanism is most likely clogged. In this case, the collapsible model is dismantled, cleaned, and then put in its original place.With a non-separable valve, it will need to be replaced with a new, previously purchased sample.
It is much worse if the water does not flow to the inlet pipe. The reason for this is the appearance of a blockage in the valve itself or in the outlet fitting. After checking these places, in the absence of a result, you will have to replace the product.
Breakdowns, their causes and elimination
There are two types of breakdown: water flows all the time or stops flowing altogether. If you find any of them, it is important to take into account that bleeding the liquid during the heating process is normal, and this is how the system is supposed to work. It is allowed to drain it when the boiler is not working.
For example, the valve mechanism is designed for 6 bar, and the pressure directly in the water supply is 7 bar. Until it drops, the water will gradually bleed away. If the situation repeats itself, you will need to change it or install a reducer at the entrance to the apartment or house.
Compact models of gearboxes can be mounted at the inlet to the boiler.
Replacement options
In some cases, instead of the safety valve for the boiler, its "explosive" analogue is installed, designed exclusively for emergency discharge of the liquid used in the heating system. Despite the fact that the functions of the two modifications are similar, they differ fundamentally in the principle of operation. Such a mechanism works only in emergency situations, since its main purpose is the salvo discharge of large masses of liquid. It will not work for the gradual bleeding of small portions of water by opening the channel. Accordingly, such a pressure regulator will not work normally.
Another option for solving the problem is to install one check valve that does not allow water to drain quietly when the pressure in the pipes decreases. However, in this case, the installed protective mechanism does not protect against pressure build-up inside the boiler. This approach turns out to be completely inappropriate and ineffective.
A check valve is a mechanism without which the operation of any water supply system is impossible. With its presence, the efficiency of the heating boiler and its safety for humans increase. In addition, the indicator of the operating resource of the heating system increases.
