Self-installation of the boiler is considered a responsible event that requires maximum compliance with the rules and regulations of the connection. A safety group is necessarily involved in the piping of the water heater, which includes a safety valve for the boiler - a small but functionally important device.
In this article, we consider varieties of safety valves, its structural features. Indeed, to install the heater without errors, you should understand the device and the principle of operation of the valve.
We also give instructions for tying the boiler and tips for installing a safety valve, and give useful recommendations on choosing the right equipment.
Types of safety valves
Safety valves are often confused with check valves, and sometimes they simply use the term “check valve” to refer to them. In fact, these are two completely different devices, although they have common features.
The non-return valve is responsible for ensuring the movement of the medium inside the pipeline in only one direction, while the purpose of the safety valve is to protect the pipe and the units connected to it from destruction caused by an increase in pressure in the network above the standard.
The replacement of concepts occurs, since the second important function of the fuse is to create a barrier that prevents the fluid from moving in the opposite direction.
Industrial-type mechanisms differ from simpler and more compact devices used in everyday life. It looks like a spring valve installed on a production pipeline
There are several types of locking mechanisms that protect complex technical devices from pressure surges. Among them are spring, magnetic spring, lever, lever-cargo devices.
The choice of this or that type is explained by the purpose of the pipeline and the characteristics of the medium that moves through it: water, oil, hot steam, chemical aggressive solutions.
For the installation of an electric boiler, one type of valve is designed - spring. They may differ in appearance, but their internal content looks the same.
Design and principle of operation of the device
To begin with, we will analyze in detail the device and the principle of operation of the safety valve.
Safety valve device
The safety valve, like other types of valves, has a simple design and is a combination of two spring mechanisms enclosed in a common metal case.
There is no fundamental difference between brass and steel products, but brass is slightly more expensive and, according to reviews, lasts longer. The springs inside the case are made of chrome steel.
Scheme in which the internal contents of the valve are clearly visible. A part is cut into the pipe that impedes the return flow of water, and a safety module with a movable nose is perpendicular
The principle of operation of the device
Both cylinders located perpendicularly have a similar design, but for different purposes. The part located along the water inside has a spring and a "plate" with an o-ring.
The spring holds the mechanism closed and prevents fluid from returning to the pipeline. The end parts of the cylinder are equipped with a male-female thread for inserting into the HVS system and connecting to the boiler fitting.
A more powerful spring is installed inside the second cylinder, which is in a neutral state even with a slight increase in pressure.
If in the line there is a sharp increase in pressure above normal, then the spring is activated and opens a hole for the release of fluid. The outer end of the cylinder is covered with a plug, screw or lever device.
Appearance of the safety valve with a plastic lever: 2 - thread for tapping into the HVS network, 3 - thread for connecting to the boiler, 8 - mini-pipe for liquid outlet, 9 - lever for forced opening
The yellow marker in the figure outlines the area on which the marking is knocked out. It indicates the maximum pressure rating at which the valve is actuated. The pressure is indicated in MPa, but it can be easily converted to atmospheres: 0.7 MPa = 7 atm.
Also on the body is an arrow showing the direction in which water moves from the cold water system to the heating tank.
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Mounted safety valve with tube
Metal valve body
Metal spring with seal
Small “stall” water outlet
Although it is convenient to drain the water through the hole in the valve, experts recommend that manual control not be used too often.
It is necessary to use the lever of forced opening of the valve as little as possible, and for prevention or repair, it is possible to drain the water in another way, for example, by unscrewing the water supply pipes.
Why is mounting a check valve insufficient?
A safety device is a component, therefore, you do not need to search in stores and select a spare part for mounting a new water heater. But during transfer, the part may be lost.
Apparently, this is why some craftsmen installing a used boiler, instead of a safety model, insert a typical non-return valve, which is strictly forbidden by the instruction.
This binding is incorrect. To drain the water, a horizontal outlet was made with a shut-off valve, and below this node a check valve is connected without a safety mechanism
Anyone who begins to operate a boiler with improper piping risks not only equipment, but also people's lives. A balanced thermodynamic effect when heating water can get out of control, and then a conventional water heater turns into a real explosive device.
Pressure increased to 5-6 atmospheres, increases the temperature of the water inside the tank to a critical boiling point, and then even higher. A huge amount of steam builds up and an explosion occurs.
The consequences of the explosion of a domestic water heater in a city apartment. Broken doors and ruined walls resulted not only in owners of equipment, but also in neighbors as a result of incorrect tying of the boiler
When using a standard safety valve for a domestic water heater, everything is different: when a critical pressure level is reached, the spring in the device compresses and releases some of the liquid out.
Due to this, the pressure inside the system is balanced and the equipment continues to heat in normal mode. For this reason, the installation of a fuse is mandatory and regulated by the installation requirements.
Thus, the safety device performs a number of functions important for the normal operation of the boiler.
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Shock and critical pressure protection
Check valve action duplication
Forced discharge of water from the boiler
Compliance with technical performance standards
Boiler manufacturers highly recommend professional installation of water heaters. If this is not possible, then all installation operations must be carried out strictly according to the instructions, in compliance with all standards and the mandatory installation of the safety module.
Valve Model Tips
As mentioned above, water heaters go on sale with a safety valve. In this regard, when buying a new model, especially a brand one, you do not need to worry about the selection of the part.
The need for a purchase arises in three cases:
- You got an already used boiler without strapping elements;
- the fuse was lost when moving;
- valve is broken or worn.
Knowing the model of the boiler, you can easily pick up a new element. In the equipment manual, you can find the pressure limit parameters - the same ones must be knocked out on the housing of the new part.
A valve with a lower limit pressure or, conversely, a product with a margin is not necessary to buy. In the first case, you will observe a constant leak from the tank, in the second - the valve simply will not work when an emergency occurs
The diameter of the thread must match the dimensions of the mounting fitting and the HVS pipeline. In addition to the device itself, flax thread will be required on the pipe or rubber gasket if flexible eyeliner is used.
Sometimes between the boiler nozzle and the fuse a valve is installed to drain the water. This is a valid, permitted strapping scheme, but under one condition - the valve must be mounted on a horizontal outlet from the water supply line. There should be no shut-off devices between the safety valve and the water heater.
Assembly instructions for piping the boiler
Installation of a protective safety valve is one of the steps in the boiler piping. The minimum set of parts for supplying the HVS line is a polypropylene pipe and a safety valve.
But we will consider another option, in which, in addition to the named elements, a tee, a drain tap and an American are involved. In addition, PP fittings are required in order to move the water supply lines to the wall.
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The first part is a ½-inch brass tee, which is required to secure the shut-off valve. It is attached using tow and a special paste, twisting by 3-4 turns
The shut-off valve is necessary to organize additional drainage of water for repair and maintenance work. You cannot install it without a tee
The metal valve is taken from the starter kit, as the boiler is new. It is necessary to carefully examine it from all sides, check the presence of springs and the condition of the lever
On one side, an arrow is knocked out on the surface of the casing, showing the direction in which water should move. The device must be fixed on the pipe so that the arrow looks up and the drain hole down
Fasten the valve with a threaded connection, using all the same tow and mounting paste. If there is an emergency discharge of excess water from the tank, then it will flow from the downward opening
Directly to the safety valve they screw the "American" - shut-off valve. For fixing, a union nut with a rubber insert is used. "American" is also installed on the second boiler pipe
Adapters are needed to draw water lines closer to the wall. If they do not interfere, then polypropylene pipes are attached directly to the bottom valve - "American"
Plastic, most often polypropylene, pipes are joined by a welded method and through fittings. It remains to connect the drain pipe to the fuse
Step 1 - Install the tee for the drain tap
Step 2 - installing a shut-off valve at the tap
Step 3 - selecting or preparing a safety valve
Step 4 - the correct fuse position on the pipe
Step 5 - mounting the safety valve on the tee
Step 6 - installation of the "American" to connect to the pipe
Step 7 - installing polypropylene adapters
Step 8 - connecting to the HVS system
A complex security node is not always used. Some installers believe that one safety valve is enough. This is the minimum version of the boiler strapping.
If tees or other adapters are not used, the fuse is fixed directly to the boiler nozzle. It can hide behind the case or drop 1-2 cm lower, which is more convenient for connection.
Installation option when the safety device is strung directly onto the boiler fitting. The thread on both elements is ½ inch. For sealing, tow was used, which is considered specifically for such compounds as better fum tape
It remains to provide a drain for water through the hole in the fuse. To do this, use a flexible plastic tube of suitable diameter. It can be white, colored or transparent.
One end of the tube is put on the mini-pipe of the valve, the other is taken out into the sewer tee or directly into the branch. Consider the possible installation options.
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Plastic drain pipe
Digging water out of a hole
Installing the tube and shutoff valve
Option to connect the tube to the sewer
Prudent homeowners lower the drain pipe into a bucket or jar - this is wrong. If the container will save, then only from constant digging.
In an emergency, the volume of water transported through the tube increases, and the capacity may simply not be enough. The only right decision is to discharge the drain into the sewer pipe by inserting it into a tee or a separate entrance.
Professional Installation Recommendations
Even such a simple procedure as installing stop valves is based on certain rules. For example, room design often requires masking the piping and security group.
You can hide devices, but subject to three conditions:
- the length of the flexible inlet or pipe from the fuse to the tank should not exceed 2 m, otherwise excessive pressure will arise on the valve spring;
- ideal fuse installation - directly to the boiler fitting, and if it does not work, then installing a tee is still possible;
- A technical hatch should be equipped for servicing the fittings.
Many are worried when they see drops of water on the valve nozzle. This is a normal phenomenon that reports the device is working.
From time to time, small pressure surges occur in the line, which provoke a minimal discharge of liquid. You need to worry when the water either does not appear at all, or pours continuously.
The line segment between the water heater and the fuse should be minimal. This is not necessary for aesthetic reasons, but in order not to create additional pressure in the pipes
It should be remembered that the independent modernization of safety devices is strictly prohibited. If you need a valve of 0.8 MPa, then you need to purchase just such a new product, and not try to somehow remodel or adjust the device to 0.7 MPa.
If you have any doubts about the operation of the safety valve, you should dismantle it and check if the spring or seal is clogged. Having problems with the water heater itself and you don’t know what to do? We recommend that you familiarize yourself with frequent boiler breakdowns and repairs. Not enough skills - invite a specialist from a service center.
To ensure that the installation process of shut-off and safety valves proceeds smoothly, without errors and misunderstandings, before installing the valve and other devices, familiarize yourself with the experience of experienced owners of boilers.
Once again about the design and principle of operation:
A few points to note:
Like any fittings for strapping, a safety valve is a necessary device for the proper operation of a water heater. It should not be confused with a check valve and should only be installed according to the instructions..
If you have difficulty choosing or installing, contact experienced specialists who will bring your boiler fully operational within half an hour.
Want to understand the purpose of the safety valve and the intricacies of its installation? Maybe you still have questions after reading our article? Feel free to ask our experts for advice in the comments section.
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