How to clean an indirect heating boiler at home
Decrease in pressure in the DHW system, change of water color, hydrogen sulfide odor. all these signs indicate the need for preventive maintenance of STBs. Flushing of the indirect heating boiler inside using chemicals will eliminate the cause of malfunction and improve the quality of the hot water supply. Regular inspection and removal of rust and scale will extend the life of the water heater.
The work of flushing the BKN performs in the service center or at home. If you want to wash the heater you can do it yourself.
How often do you need to clean?
Cleaning from dirt, limescale, and other deposits water heater requires regular. To determine the frequency of cleaning, you need to consider several basic factors. If the water flowing from the pipes is hard (it has a high content of various harmful impurities), it is worth cleaning the unit once every 6-8 months, then with a normal content of impurities this procedure is sufficient once every 2 years, quite enough for trouble-free operation of the water heater. In addition, if you use water too often with a temperature regime of over 50 degrees, cleaning of the boiler from scale will have to be carried out much more often.
Determining the level of water hardness is simple enough, white plaque will help. With frequent scaling of the mixer, detergents foam too little, an indicator of the presence of high lime content. But in addition to home methods, there are special devices that determine the level of hardness.
Boiler too often used the maximum possible level of heating, leads to the rapid emergence of limescale. Clogged heating element may not work well enough, so the device fails during operation, periodically turning off automatically, turning off its function before.
After the first symptoms of the problem simply ignoring, also the lack of timely cleaning, can lead to overheating of the mechanisms, which may require its further replacement.
Check Valve Cleaning
The main problem for all users are usually the question of how to properly clean the water heater, without removing it, expending less energy. The situation when periodic cleaning is carried out, removal may not be necessary. It will be enough just to separate the support flange with a heating element, perform descaling. But the problem worsened, the removal of the entire structure is an expected outcome. You may need the help of a specialist if the situation is too neglected.
How to flush a water heater from rust
Consider descaling and rust removal together, as the methods are similar. Flushing the water heater without disassembly, step by step:
- The boiler is disconnected from the mains.
- Drain (part of the water can be left, remove 2/3), options:
- Drain valve: it is opened after shutting off the supply.
- The easiest and fastest way. close the cold supply from the riser, the hot is already blocked (this is required for the water heater). Unscrew and disconnect the two hoses (hot and cold). If the spigots are at the bottom, the water flows out through the 2 holes, so you need to put a container in advance.
- By opening the safety valve, connecting a pipe to it for drainage, but the procedure will be long (80 liters in 2 h).
- The cold spigot is the riser, the hot faucet is shut off so that the water does not burst out in a strong stream. Put a basin on the mixer. Disconnect the hose from the safety valve, unscrew it with an adjustable wrench and remove. Water through a cold branch will flow weakly, as the hot tap is closed, it is opened, air enters, the flow increases, thus (closing/opening) regulate the intensity. If there is a valve at the outlet of the water heater to the faucet, you can use it.
- Flush with solution:
- Prepare a mixture of citric acid or a special agent according to the instructions.
- To the cold spigot (inlet) of the water heater connect a flexible tube, raise it above the level of the tank, pour through the watering can.
- Pour 1 liter of water so that the mixture does not remain in the hose, which is then removed, make a reverse connection, open the supply (from the cold riser).
- Wait 1 to 2 days. or according to the instructions of the means, then the supply valve is closed, the hot tap is opened, releasing the dirty liquid, or you can do the drainage of the above described ways.
- The final stage of the flushing procedure: several times heated to the maximum, running the full volume of liquid to remove odor, particles of substances.
Dissolve limescale and difficult to remove by simple rinsing without disassembling the tank. Mechanical removal of the softened layer will be required for one hundred percent effect. To do this, the tank is disconnected from the water supply and wiring, make a drain, disconnect spigots.
How to disassemble the water heater for the two model variants:
- non-disassembled. remove the protective cover from below, unscrew the bolts and carefully. it is important not to damage the enamel. pick up with a screwdriver around the perimeter. Under the cover there are contacts, wires. Disconnect, remembering the location (take a picture on your phone). Unscrew nuts of thermostat, TEN, push flange inside, unscrew, pull out. Cleaning is carried out through the hole;
- demountable (characteristic for combined BKN, non-pressurized models):
- Remove the entire top, the bottom, under which part of the body with a large opening. It is enough to unscrew the screws, remove the gaskets. There is a variant when it is necessary to unscrew the spigots;
- remove the large segment with the heating element, thermostat.
Disassembly stages during maintenance of the tank water heater (for variety of photos of different models):
Some models of boilers can not be disassembled by turning upside down. the heating element will fall inside, scratching itself and the walls.
Removing the heating element by pushing it inside, bringing it to a convenient position for pulling it out:
- Do not use hard brushes, metal sponges and tools. Over time, even microscopic scratches expand, accumulate sediment, corrosion begins;
- Do not knock, especially the heating element;
- Remove with hands, soft sponges without excessive force. Usually the upper loosened crust is easily removed, and under it there is a hard layer, if it does not yield, again pour the flushing agent, the operation is repeated.
Why is the water heater safety valve leaking. what to do
Owners who have installed a storage water heater in their home, often have questions about the work of its safety valve. Water leakage from this device. is this the norm or a breakdown? And if the flow of water must have a place, then in what amounts and how often? Design and operation of safety valve for the boiler we have already reviewed. In this material, the master plumber will tell you how to determine the fault of this device and how to solve the problem of its leakage.
Why there is excessive pressure in the storage water heater
Water expands by approx. 3% of its volume when heated. This means that in a boiler with a capacity of 100 liters of water heated from 20 to 80 ° “excess” is almost 3 liters of water. If you remember that the liquid is almost incompressible, it is easy to simulate the situation in which the metal tank of the boiler leaks and fails.
To prevent a possible emergency situation, water heaters are equipped with safety valves, through which the excess water is discharged to the outside.
In other words, the safety valve is a pipe valve designed to protect devices from destruction in the event of excessive pressure in them by automatically release the excess fluid into the environment.
The safety valve is directly actuated by the process medium and is a direct-acting device. When the medium returns to normal the valve returns to its initial position. This means that as long as there is no excess pressure in the heater, the valve is in its initial position and does not release water to the outside. When the pressure rises above the limit value, the valve opens and discharges the excess liquid until the pressure drops below the set value.
Design of a water heater safety relief valve
The water heater safety valve consists of two parts:
How a safety relief valve works is an example of a typical direct-acting spring loaded valve set to a certain maximum permissible pressure. When it is closed, two forces act simultaneously on the valve sensing element: one coming from the pressure of the liquid in the boiler and the other from the set point adjuster or spring, preventing the valve from actuating and opening.
If the force of the liquid pressure exceeds that of the spring, the valve opens and the water is released. When the pressure of the medium drops, the valve closes and the water discharges no more.
The safety valve setting can be adjusted with a set point adjuster.As you can see, the design of the safety valve is very simple, but at the same time the properly functioning valve is a guarantee of safe operation of the water heater and reliably protects against such troubles as overheating of the device and possible boiling of water in it, which can happen when the thermostat is not working.
As you already know, the safety valve for the water heater serves to release excess pressure from the tank, which appears during the heating of water. In this case the leak can occur in several cases, each of which we will consider in detail:
- The first thing that comes to mind is that the valve itself is broken. Here it should be noted that if you have purchased a part from a dubious manufacturer, this scenario is quite possible. Quality valves installed in a branded water heater, however, rarely suffer from such defects. That’s because it’s so simple, there’s nothing to break. Inlet valve, spring and check valve. That’s it, there’s nothing else there. Chinese products are made without observing elementary standards and can become unusable.
- But even quality valves from a reputable manufacturer can get clogged. And again, not by themselves. This usually happens after all the water in the water heater has been drained through it. Then pieces of limescale or other foreign particles can get into it, which will prevent the spring from closing the valve tightly, resulting in a constant leakage.
- The initial stage of work provides for water dumping in boilers. All the same laws of physics are at work here. Cold water flows into the tank, the pressure is equalized. Then the water begins to heat up, which causes the water to expand and its surplus flows out of the safety valve.
- Sometimes the safety valve for the water heater leaks due to high pressure in the water system. In this case, as you can guess, neither the valve, nor the boiler is at fault. over, they properly perform their task by letting the excess pressure out on time. Well, to eliminate this cause will have to other ways, without touching the water heater at all.
The permissible quantity of water flowing out of the valve
Before answering this question specifically, with numbers, it is worth focusing on two things:
- First: water from the safety valve MUST drip. This is what in most cases shows that the valve is in working order, and the water heater is protected from overpressure.
- Second: it is not for nothing that manufacturers equip the valve with a transparent drain tube. This is done so that you can visually monitor how much excess water is discharged.
And now in grams. With all correct indicators and correct actions both in the plumbing and in the boiler operation, the safety valve should release from 1.5 to 3% of the total volume of the tank in a day. It is easy to calculate in liters. If the tank is a 1.5 liter, then the discharge will be equal to 3-5 liters. If this indicator is exceeded and severely, it is worth to start worrying and take some actions.
To check the functionality of the safety valve is easy: just turn on the water heater and do not open the hot water tap until the water heats up to the maximum permissible temperature. In this case the safety valve should discharge (drip) excess water.
If the water in the boiler heats, but the valve does not work, it means that it is defective, and it must be replaced by a new valve, and after installation check its performance.
But before you start repairing, you need to make sure that the hot water intake valve is serviceable and does not leak. If it is defective, the “superfluous” water from the boiler will flow through it and the situation in which the valve can work, simply will not occur.
Also the valve will not work if the device thermostat is set to partial heating of water (30-40 ° C) or from the heater is taking hot water, which also reduces the pressure level in it.
- If the valve was not qualitative and the reason for its leakage in the breakage, the only way out is to replace it.
- If the cause is a clog, of course you can dismantle, disassemble and clean. But is it worth it? You can buy a new valve at any specialized store, and they cost very inexpensive. When buying pay attention to the country of manufacture, ask the seller or read the passport to the maximum pressure it is designed for and in any case do not save, buying cheap Chinese analogues.
- If the water is dripping, which is called according to indications, and fixing the problem is not required, but its sound bothers someone, and the system is not equipped with a drainage tube, it is quite possible to install it yourself.
- If the reason is the high pressure in the pipeline, then you should not wait for mercy from the water utility. It is necessary to install a pressure reducer. And not in front of the boiler itself, but at the entrance of the system to the apartment.
In the story. Why do we need a magnesium anode and a safety valve in the boiler
In the story. Leaks from the safety valve from the water heater
In the story. What does the operation of the boiler without a safety valve lead to?
To summarize, a safety valve is a mandatory device for installation in devices working under pressure, especially if they are used in the home.
Without it, the water heater should not be operated. Especially dangerous is an independent improvement of the device and replacing the safety valve with a check valve.
How and where to put the check valve of the boiler
The place of the protective unit is the cold supply pipe, between the blocking handwheel of the riser pipe and the water heater connection. You can cut directly into the pipe or, if there will be a drain valve in front of it, first install a tee not further than 200 mm from the outlet to the EVN.
Vertical location is more common. But there are different bends and pipe positions, horizontal installation is allowed.
If the parameters of the water supply are not stable, then the scheme includes a pressure-reducing valve in front of the safety valve (on the supply side), complex models are already with it.
Installation is standard, you will need gasket, adapters (“American”), fittings for plastic pipes, flexible liner with coupling nuts. The tee is screwed on 3. 4 turns.
Install the valve on the water heater must be no farther than 2 meters from the boiler, the gap must be minimal, otherwise there will be increased pressure on the spring and an inadequate response. The correct option is to connect directly to the nipple of the tank.
In front of the safety group (in the direction of the tank) there should not be any fittings according to safety rules, but the drain through the drain with a very narrow passage is slow. 3, 5 hours, so sometimes put a separate valve in front of it for this purpose. The main thing is to periodically check that the tee is not clogged, otherwise the way to the safety gate will be closed, the tank will burst.
This element of the water heater is designed to ensure the safety of the device in case of pressure drops that occur during operation. Liquid coolants tend to expand when heated. If its temperature exceeds 80-90°, its volume will increase to 3%. So, in a classic heater of 50 liters, you have to put 1.5 liters of water somewhere. The basic principle of the safety valve for the boiler is the discharge of excessive amounts of hot water.
If you do not install protection, the proper functioning of the water heater can be forgotten, even if you follow the other recommendations for operation. Sooner or later, the supply head limits will be exceeded, and the excess coolant will be flushed out into the space of water pipes or into the toilet tank. This is not only energy-consuming, but also leads to trouble over time.
To understand what the valve on the water heater is installed for, it is worth remembering the school program. According to the law of physics, water expands when heated. The liquid is inside a sealed container. If there is no water separation, the pressure increases and the tank can rupture. To prevent an accident will help safety valve for the boiler, bleeding excess liquid from the tank.
On the forums, you can meet the information, where they advise just not to put a check valve. Then there is no need to install the valve to release excessive water pressure. According to them, when there is excess pressure, some of the water will escape back into the pipes. Partly correct advice, but the system will operate as long as the plumbing is stable. The fallacy of this advice is in three reasons:
- There are no consistently functioning plumbing systems without failures;
- Without a check valve in an empty pipe all the water from the tank will go;
- The bare heating element will heat the air inside the empty tank.
Now consider the end result of the problem encountered. If there is a plumbing failure, the pipes are left empty. There is no check valve on the inlet connection, and the water from the storage tank flows freely into the system. The thermostat will turn on the heating element when the temperature drops. Without water, the heater will simply burn out, but that’s only half the problem.
There is another danger. The heating element has heated up and water appears in the water supply. There is a large amount of steam and excess pressure inside the tank that does not have time to drain back into the pipeline. The tank is guaranteed to burst in several places. Boiling water rushes into the apartment. For this reason, it is better not to get wise, and simply install a discharge valve for water.
Safety valve, features of the device and installation
One can easily guess by its name, that the main function of the safety valve is to control the pressure inside the boiler. In fact, the standard design includes two check valves and a safety valve, Fig.
To understand how to work with the design, it is necessary to understand the design of the boiler safety valve:
- Both control valve elements are assembled in a T-shaped housing made of nickel, aluminum-iron or brass alloy. A check valve is installed in the vertical part of the body and a safety valve in the horizontal part;
- There is a red or blue control flag on the safety valve stem, which can be used to forcibly discharge some water from the boiler;
- The control plates or petals of both valves should be pressed against the supporting surface or seat when in service;
- At both ends on the inlet and outlet pipe of the body is a pipe inch thread, most often its size on the safety valve for the boiler ½ inch. For a 100-200 l tank, a boiler safety valve is usually installed on the ¾ inch.
As an example of a high quality appliance, we can recall the safety valve for the boiler gorenje, photo.
The brass body and high-pressure castings provide long service life even when installed on cheap Chinese boilers. The only drawback is the high price, not less than 15. each. But if you consider that the installation of a safety valve will avoid major trouble, it makes no sense to save on safety.
What to do if the water heater safety valve leaks
For quite a long time in the apartments appeared another type of electric appliances storage water heater for hot water supply. It has become very popular, as it makes it possible not to depend on the whims of the utilities. One of the key elements of boiler piping is a safety valve. If for older models of boilers it had to be purchased separately, but now it is included in the obligatory set. From time to time water leaks from it, and many users logically think about the breakage.
It should be understood that the discharge of excess water is one of its functions. Therefore, before you take decisive action to dismantle and replace the device, it is necessary to analyze what volumes of water, and with what frequency leaks.