Where should the valve be located on the boiler? Adjusting the safety valve for the water heater. Features of installation and adjustment of valve devices
When operating any heating equipment, it is very important to follow all recommended safety precautions. This applies not only to large installations that are used in construction or production, but also to compact devices, such as household water heaters.
If you ignore safety rules, the consequences can be extremely serious - after all, we are talking not only about your life, but also about the lives of the people around you. A safety valve is a very important thing in equipping a home water heater, which, unfortunately, many people forget about. In this article we will tell you what this device is for, how it works, and how to use it correctly.
Purpose
To understand the purpose of the safety valve, first let’s remember the basic things from the school physics course. It is known that water tends to increase in volume when heated. If you heat water to 80 degrees (the approximate maximum temperature of hot water from the tap), its volume will increase by 2 or 3% - this depends on what the temperature was at the beginning of heating.
Since the container in which the water is heated in the boiler is sealed, the pressure inside this container inevitably increases with strong heating. An uncontrolled increase in pressure may result in an explosion of the device. This is where the safety valve comes to our aid. It performs the following functions:
- prevents hot water from flowing back into water pipes;
- normalizes the pressure inside the water heater, minimizing the likelihood of water hammer;
- gets rid of excess water by dumping it as soon as normal pressure and temperature are exceeded;
- makes it possible to safely drain the water from the boiler for maintenance.
If you are faced with the question of whether to install a safety valve on a boiler, we bring to your attention a video by Gennady Myagkov, in which he explains why and when it is necessary to install a valve and how it works.
Design and principle of operation
Despite its rather wide functionality, the safety valve has a very simple structure: its main elements are two cylinders - large and small.
- Big cylinder is a kind of “check valve”. There is a flap inside it called a “poppet valve”. This valve is activated by a small spring. At both ends of the large cylinder there are threaded parts that are needed to connect the safety valve to other elements of the boiler.
- Small cylinder fixed perpendicular to the large one. Both ends are plugged with plugs, and there is a drainage tube on the body. There is also a check valve inside the small cylinder, which operates in the opposite direction to the first.
How does a safety valve work? An increase in water pressure inside the boiler activates the check valve spring. It opens, allowing water to fill the tank. As soon as the water reaches the desired level, the pressure inside the water heater increases and the check valve slams shut. As the water in the tank is consumed, its reserves will be replenished automatically.
The check valve inside the small cylinder is rated for higher pressure. As soon as this indicator becomes critical, a spring is activated, opening the valve. Thus, excess water will be discharged.
Kinds
There are several different modifications of check valves for boilers. They differ in certain key parameters. For example, according to the installation method, check valves are divided into:
- non-returnable;
- reception rooms;
- steel;
- ball
Depending on the principle of operation, the following types of check valves can be distinguished:
- straight;
- indirect;
- designed for two positions;
- proportional.
Finally, there are several more types of check valves for boilers based on the height of the constipation:
- full lift;
- mid-lift;
- low-lift.
With release handle
One of the most common types of check valves that are equipped with water heaters is a valve with a release handle. Let's talk briefly about its structure and principle of operation.
The design of a check valve with a release handle has the following elements: a body, a water release fitting, a forced pressure release handle, a safety valve spring and a check valve spring.
Under the influence of water pressure, the spring of the check valve is compressed, as a result of which the poppet valve rotates and allows water access to the tank. Once enough water has been collected, the check valve returns to its original position.
The release handle is needed to, if necessary, forcefully relieve pressure inside the system. As soon as the pressure exceeds the permissible maximum, a safety valve is activated, through which excess water is discharged, thereby normalizing the pressure.
For indirect heating boiler
Many apartments have indirect water heaters. Indirect heating does not occur in the boiler itself, but in another device, most often in a heating boiler. Thus, the operation of the indirect boiler and the boiler is closely interrelated. For this type of water heater, it is necessary to select a suitable safety valve.
All the characteristics we need are indicated in the technical data sheet of the device, so be sure to study this document before purchasing. It is important to know the permissible operating pressure of the device - you need to focus on it, and not on the pressure in the water pipes.
Can a safety valve be replaced with a non-return valve?
Users of household water heaters often ask the question: “Is it possible to install a non-return valve instead of a safety valve?” Technically this is possible, but under no circumstances should you do this. If you make such a replacement, the boiler will turn into a balloon that can burst at any moment.
For example, when water is heated to 150 degrees, the boiler can easily withstand the rapidly increasing pressure. However, if you open a hot water tap at this moment, the pressure inside the water tank will begin to drop quickly. Next, the boiling point will drop to 100 degrees, but it will not have time to cool down so quickly. As a result, the water will instantly boil, a huge amount of steam will be released, the pressure will jump up and a rather strong explosion will occur.
When choosing a safety valve for a household water heater, use the recommendations that experts have compiled for you.
- Among the variety of designs, the spring mechanism is the most reliable, as it is able to withstand water pressure well.
- We must not forget about such a factor as valve capacity. We advise you to choose a low or full lift device.
- Consider the water supply and sewer systems in your home. If excess liquid will be discharged into the atmosphere, choose an open safety valve, and if into a specially equipped pipeline, then choose a closed one.
- When choosing a safety valve, you should remember the maximum allowable pressure in the water heater system. If it is higher than indicated in the technical data sheet of the device, the valve will not be able to function normally.
Checking for serviceability
At home, you can quite easily find out whether the safety valve installed on the water heater is working properly. To do this, you just need to set the temperature regulator to the maximum value and open the hot water tap. If, after the water in the boiler has heated to the required temperature, excess liquid begins to flow out through the safety valve, then it is quite suitable for operation. If water does not flow through the valve, it is most likely faulty.
Not only the duration of its operation, but also the level of safety during operation will depend on the quality of the piping of an electric storage water heater. This is one of the most serious moments when installing a boiler and requires special attention. Correct strapping for a water heater is called a safety valve built into the cold water supply system.
The integration of a safety valve protects against a sudden increase in pressure in the internal part of the unit, significantly exceeding the norm. The question arises, what is the reason for such a jump? As we were able to establish, during heating the liquid increases in volume and, therefore, expands. Due to the tightness of the heater reservoir, the resulting excess simply has nowhere to go - the tap is turned off (as a rule, a check valve is installed on the supply).
Further heating of the liquid may cause increase in pressure. At this moment, there is a danger of exceeding the tensile strength of the unit and rupturing its walls. To avoid such an explosion, a safety valve is installed for the boiler.
Some owners may ask: is it worth the hassle of installing a fuse when you can simply remove check valve. Experts answer this as follows: at a relatively high and uniform pressure in the water supply system, such a scheme will function, but for some time. This does not mean that such actions are a way out of the situation. The fallacy of this scheme is due to a number of reasons:
- The pressure in the water supply system is not stable.
- Excess water is removed from the boiler into the water supply, exposing the heating element.
- By heating the air, the boiler will fail after a while.
Burnt out heaters are not the biggest problem. Much more importantly, there is a danger of unexpected pressure changes in water pipes. The liquid, falling on the heated heating element, quickly turns into steam, sharply increasing the pressure. Under such conditions, the walls of the boiler are guaranteed to rupture. A large amount of boiling water and steam, pushed by pressure, will fill the room, threatening everyone in it with serious injury.
Principle of operation
In addition to the main structure, a safety valve for a water heater consists of several more elements. They are housed in a brass or nickel housing. In most cases, the device looks like an inverted letter T. It is attached to the bottom of the tank on the water heater check valve, capable of preventing liquid from leaking out of the tank when the pressure in the pipes drops.
The perpendicular branch contains another valve, which is activated after the pressure increases and discharges excess liquid through the fitting. The operating principle occurs in several stages.
- If the tank pressure is lower than that occurring in the pipes, when filling or opening the tap, the poppet plate in the check valve is pressed out by the water pressure. When the pressure level returns to normal, a spring mechanism presses the plate against the protrusion of the housing, limiting the flow of liquid.
- During active heating, the temperature of the liquid slowly increases, and at the same time the pressure increases. Until it reaches the maximum value, the mechanism is not activated.
- After reaching the limit level, the pressure compresses the fuse spring, opening outlet channel of the fitting. Excessive volume of liquid from the reservoir is removed through this channel. After the pressure drops to the normal level, the spring closes the flow and water removal stops.
Based on the above, it can be understood that liquid will periodically drain from the fitting channel. This phenomenon occurs when water is heated and pressure in the water supply system decreases. If you regularly notice water at the fitting, this means that the safety valve for the boiler is operating normally.
However, at the same time there is a need to drain the flowing liquid. To carry out the procedure, a tube of a suitable size is attached to the nozzle: it must be tighten with a clamp to ensure secure fastening. The standard operating pressure in the water heater tank is from six to ten bar. Without reliable fastening, the tube will simply break off, so the choice of clamp must be approached with special care. Tighten it tightly and lead the tube to the nearest sewer drain.
The tube to the fitting should be transparent; the ideal option would be a reinforced hose. This helps control the performance of the system, and the reinforcement provides additional protection against pressure.
Valve operating principle
Features of different types of valves
If we talk about a standard safety valve for a boiler, they are not very different in appearance. However, there are small nuances that are responsible for the ease of use of the device.
The image shows valves equipped with release levers. Their purpose is to periodically check serviceability:
- the lever is moved to a vertical position;
- it activates the spring mechanism, pulling it along with it;
- As a result, a channel opens through which water flows.
Release lever on valve
The differences between the models shown are that the valve located on the left has a fixed lever special bolt. This eliminates the possibility of involuntary opening and complete removal of liquid.
The following image shows valves without a positive fluid release lever. The left model has a threaded lid at the top. It is intended for maintenance of fuses. If necessary, unscrew it to remove blockages, scale and other contaminants.
Valves without lever
The right model is the least preferred option. It does not have any markers, a water release lever or a service hole. This is the cheapest and lowest quality product coming from China. There is no need to talk about reliability and durability. You can use it only as a temporary replacement at your own peril and risk.
Pressure rating note
There are a few other notable differences. The arrow shown on the body indicates water flow direction, as well as an inscription informing about maximum pressure, which the device can withstand. At first glance, the details seem insignificant. But if you can easily figure out the direction of liquid flow (to do this, just look at the location of the poppet-type valve), then the situation with ratings is more complicated.
By what signs can you distinguish between a six and ten bar valve? Only by experience. You may ask, how do suppliers differentiate them? No, only according to the inscriptions in the documents. Experts do not recommend purchasing devices without any markings on the case. Of course, the cost of labeled products may be higher than that of analogues, but it is better not to save on this issue.
Fitting shape
In addition, it is worth paying attention to the shape of the fluid removal fitting. In the left model this element is quite long and has a nonlinear shape. It will be easy to attach the tube to it, and the length is quite enough for secure fastening with a clamp.
The shape of the similar element in the right model is different. It has a characteristic expansion at the end, but the most important thing is the length of the fitting. It will be quite difficult to install the tube on it and even more difficult to ensure a secure fit. The use of artisanal methods will not guarantee a good result, and difficulties with drainage may arise in the future.
For large volume boilers
Each of the devices described above is designed for a storage water heater with a volume of fifty to sixty liters. For larger tanks, other systems are used, each of which integrates special equipment. Most often this ball pressure gauge or a valve that controls pressure.
Ball pressure gauge
They are equipped with a fitting for removing liquid standard thread to increase the reliability of fastening and solve the problem with clamps. This type of device has a high price, but the level of quality is significantly higher than other systems.
A significant disadvantage for many owners can be the appearance of the faucet. Especially for such people, the production of fuses has been launched, which not only have practical benefits, but can also decorate the interior of the room. Their cost can significantly reach the price of the boiler itself, so everyone will have to assess the feasibility of such a purchase for themselves.
Installation of other valves
There are cases when, instead of the factory pressure surge protection system, a heater tank is installed blast valve. It is intended primarily for emergency removal of liquid into the heating system. Although their functionality is largely the same, the basic principle of operation is fundamentally different.
The blast-type valve performs its functions only during an emergency. It is needed to urgently remove all water from the tank. It is not intended for periodic bleeding of small portions of liquid. Considering all this, you should not expect correct functioning from such a craft.
Another example is mounting only check valve. Its mechanism will not allow liquid to drain at low pressure in the system, but it will not be able to save you from sudden surges in the tank. As practice shows, such an assembly is also not functional.
Diagram of all components of safe operation of a water heater
Selection and installation
The fuse should be selected based on the pressure that the device can withstand. This figure is usually included in the registration certificate. In addition, the volume of the tank may influence the choice. There are systems with a response threshold of six, seven, eight, ten Bars. These are the most common values for tripping the fuse.
The installation process is quite simple.
- Wrap a special tape or flax tow around the threads for a tight seal.
- Screw the valve onto the pipe.
- Continue to tighten it all the way with your hands, and then turn it a few times using the wrench.
- Do not forget about choosing the right place for its installation. Experts recommend attaching it directly to the cold water inlet pipe.
After this, you can install a check valve system, or as it is also called - constipation. But these are reinsurance measures; a device with similar functions is already included in the fuse system, and it is also often integrated into water meters.
The diagram demonstrates ball valve location. It is used to remove liquid from the tank during winter storage or during dismantling. Drying may also be required during maintenance or repair. In most cases, it is installed on a tee, which, in turn, is connected to the fuse system.
You should not skimp on such an important detail as a fuse. This device will not only help you maintain the functionality of the heater, but may also save you from serious injury. Pressure surges in the water supply are a common occurrence, and no one is immune from tank failure. Spend some time installing safety valves to ensure your safety.
Not only the service life of the equipment, but also the safety of residents depends on the correct piping of an electric storage water heater (boiler). That's how serious things are. And its correct piping is a safety valve for a cold water supply water heater.
What is it needed for
Installing a safety valve prevents the pressure inside the device from increasing above the standard value. What causes blood pressure to rise? As you know, when heated, water expands, increasing in volume. Since the boiler is a sealed device, there is nowhere for the excess to go - the taps are closed, and there is usually a check valve at the supply. Therefore, heating the water leads to an increase in pressure. It may well happen that it exceeds the tensile strength of the device. Then the tank will explode. To prevent this from happening, they install a safety valve for the water heater.
This is what an installed pressure relief valve looks like in a water heater
Maybe there is no need to install a safety valve, but simply remove the non-return valve? At a sufficiently high and stable pressure in the water supply, such a system will work for some time. But the solution is fundamentally wrong, and here’s why: the pressure in the water supply is rarely stable. There are often situations when water barely flows from the tap. Then the hot water from the boiler is forced out into the water supply system. In this case, the heating elements will be exposed. They will heat the air for some time and then burn out.
But burnt-out heating elements are not the worst thing. It’s much worse if they get hot, and at this time the pressure in the water supply rises sharply. The water that gets on the hot heaters evaporates, a sharp increase in pressure occurs - with a jerk - which leads to a guaranteed rupture of the boiler flask. At the same time, a decent volume of scalding water and steam escapes into the room under high pressure. What this could mean is clear.
How does it work
It would be more correct to call a safety valve for a water heater a valve system, since there are two of them in the device.
Safety valve device for boiler
They are located in a brass or nickel-plated case, which looks like an inverted letter “T” (see photo). At the bottom of the housing there is a check valve that prevents the outflow of water from the water heater when the pressure in the system decreases. In the perpendicular branch there is another valve, which, if the pressure is exceeded, allows some of the water to be released through the fitting.
The working mechanism is as follows:
- While the pressure in the boiler is less than that in the water supply (when filling or when the tap is open), the check valve plate is pressed out by the flow of water. As soon as the pressure is equalized, the spring presses the plate against the protrusions of the body, blocking the flow of water.
- When the heating is turned on, the water temperature gradually increases, and with it the pressure also increases. As long as it does not exceed the limit, nothing happens.
- When the threshold level is reached, the pressure compresses the safety valve spring, and the outlet to the fitting opens. Some of the water from the boiler is released through the fitting. When the pressure drops to normal, the spring closes the passage and the water stops flowing.
Related article: Important advantages of frame pools
Based on the principle of operation, it is clear that water will constantly drip from the fitting. This happens when the water heats up and the pressure in the water supply decreases. If you periodically see water on the fitting, then everything is working normally. But the draining liquid must be drained. To do this, put a tube of a suitable diameter on the pipe and secure it with a clamp. The normal operating pressure of the boiler is from 6 Bar to 10 Bar. Without mechanical fastening, the tube will be torn off in no time, so we select a high-quality clamp and tighten it well. Place the tube into the nearest sewer drain.
One more point: the tube for the fitting needs to be transparent and preferably reinforced (the so-called “herringbone”). Why reinforced is understandable - because of pressure, and transparent - to be able to monitor the performance of the device.
Types and varieties
If we are talking about conventional safety valves for a water heater, then they look almost the same, only the nuances differ. But it is these small details that are responsible for ease of use.
Safety valve for boiler with forced pressure release option
The photo above shows two safety valves with release levers. They are needed for periodic performance checks. The lever flag is lifted up. It pulls the spring behind it, freeing it to release water. This check should be carried out approximately once a month. You can also empty the boiler tank by raising the flag and waiting for everything to drain.
The difference in the presented models is that the model in the photo on the left has a lever secured with a screw. This eliminates the possibility of accidental opening and complete discharge of water.
Two more differences are striking. This is an arrow on the body indicating the direction of water movement, and an inscription showing what pressure the device is designed for. Seemingly minor details. But if you can figure out the direction of water movement (look in which direction the poppet valve is turned), then the nominal value is more difficult. How to distinguish, for example, whether it is 6 Bar or 10 Bar? Only checks. How will sellers differentiate them? No way. By boxes. What if they put it in the wrong box? In general, it is better not to take it without markings on the case. These are usually the cheapest of the Chinese designs, but the difference in price is not so great that it is worth the risk.
Also pay attention to the shape of the water discharge fitting. The model on the left has a long fitting and has a non-linear shape. The hose fits on it quite easily and is long enough to install a clamp. The shape of the fitting on the model on the right is different - with an extension towards the end, but more importantly, the fitting is short. You can still pull the hose onto it, but the clamp is questionable. Unless you crimp it with wire...
Related article: Blue color in the interior - photo
The following photo shows the safety valves without a forced pressure release flag. The one on the left has a threaded cap at the top. This is a serviceable model. If necessary, you can unscrew the lid to remove clogs, scale and other contaminants.
Safety valves - serviceable and not
The model on the right is the worst option. No markings, forced resets or maintenance. These are usually the cheapest available, but this is their only advantage.
All of the above models are suitable for water heaters with a volume of up to 50-60 liters. Larger boilers come with other models, many of which have built-in additional devices. Typically this is a ball valve and/or pressure gauge to control pressure.
For boilers up to 200 liters
The water drain fitting here has a standard thread, so there will be no problems with fastening reliability. Such devices already have a fairly high price, but their quality and reliability are much higher.
With pressure gauge and original
Not everyone likes the appearance of these devices. For those who attach great importance to aesthetics, very attractive devices are produced. Their price, however, is comparable to the price of an expensive water heater, but it’s beautiful.
Is it possible to install other valves?
Sometimes, instead of a special safety valve for a boiler, a blast valve is installed, which is intended for the emergency release of heating water. Although their functions are similar, the main mode of operation is fundamentally different. The demolition device should only be used in emergency situations. It is designed for volley discharge of a large volume of liquid. It is not suitable for constantly bleeding small portions of water. Accordingly, it will not work correctly.
Another case is to install only a check valve. It will not allow water to drain when the pressure in the water supply decreases, but it will not save you from increasing pressure in the boiler. So this option doesn't work either.
How to choose and install
Select a safety valve for a water heater based on the pressure for which the unit is designed. This number is in the passport. The volume of the tank also influences the choice. They produce devices with operating limits of 6, 7, 8, 10 Bar. Basically, all units are designed for this pressure. So everything is simple here.
Installation is simple: flax tow or fum tape is wound onto the threads, after which the valve is screwed onto the pipe. Twist it all the way by hand, then another one or two turns using keys. It is much more important to choose the right place to install it. When installing a water heater, this valve is installed directly on the cold water inlet pipe.
