Hot water is necessary in everyday life - this is indisputable, and a hot water supply system (DHW) is necessarily laid in the projects of modern residential buildings.
Apartment buildings are provided with hot water centrally - by connecting the DHW system to the main heating plant, and the owners of cottages, in the absence of such an opportunity, solve this issue by installing water heating devices.
In addition to expensive double-circuit heating boilers, also designed for connection to the DHW system, there are many other types of water heating devices that differ in the type of energy consumed, design and other technical characteristics.
At the same time, ways to meet the needs of housing in hot water are constantly updated with new technologies, and existing heaters for tap water are being improved. Consider the most common types of units used to heat cold water in the plumbing system and water intake points.
The purpose of domestic water heaters and the requirements for them
The hot water units are designed to meet domestic hot water needs and, depending on the type, can be used to fully supply the DHW system or as compact devices mounted on separate water intake points. Some types of water heaters can be used as alternative devices used during periods of repair of the main equipment or main heating plants.
According to the type of energy consumed, water heaters are divided into electric and gas, but the following requirements are imposed on both types of these devices:
- safety - a set of parameters that minimize the likelihood of an explosion or fire in a building, injury to a person or poisoning;
- efficiency - the power of water heating devices should provide the actual demand for hot water, and the costs of operating heaters should be commensurate with the effect;
- aesthetics is a natural condition for the demand for modern household equipment.
Types of water heating devices
According to the mechanics of its heating, household water heaters produced today can be divided into the following groups:
- water-heating devices of flow heating;
- storage water heaters;
- aggregates of flow-accumulative heating.
Let us consider in more detail these groups, represented on the market by both gas and electric appliances.
Flow units
Flow-type water heaters, which are divided into gas and electric according to the type of energy consumed, automatically turn on when a water tap is opened and heat the moving water flow through the walls of the water supply. Depending on the type, a flow-through water heater can provide all consumers of the DHW system, some of them, or one point of hot water intake.
Gas water heater
This household water heater, sometimes called the Junkers column after the inventor, has been produced for more than a hundred years, but, thanks to its merits, has not lost its popularity today.
Simplified, the geyser consists of a housing in which a burner, a heater and a security system are mounted. The first models of the device worked according to the following, very simple principle.
The hot water line passed through the gas column heat exchanger, in which the burners were located. On the case there were levers for manually supplying gas to the burners, and next to them there was an ignition device - a constantly burning small nozzle. To supply hot water to the point, a water tap was opened, after which gas was supplied to the burners by manually shifting the lever. The flame of the burners heated the heat exchanger, which transferred heat to the water passing through it. To stop the supply of hot water to the faucet, the gas was also manually shut off, the burners were extinguished, after which the faucet of the water intake point was closed.
As a result of consistent design improvement, a modern gas water heater is a complex water heating equipment with a high degree of operational safety, the design options of which allow you to choose a device in accordance with the style of finishing the room.
Such a water heating unit consists of the following main components:
- metal body;
- burners with an ignition device;
- automatic ignition system;
- heat exchanger with a copper coil;
- a set of devices for automatically stopping the gas supply in case of overheating of the unit, a drop in draft in the chimney, the extinction of burners, excess or insufficient water pressure in the water supply system;
- mechanisms for manually adjusting the intensity of gas combustion and water movement;
- diffuser with outlet for connection to the chimney;
- inlet and outlet fittings for water;
- gas supply fitting.
When the water tap is opened, the geyser turns on automatically - by applying water pressure to the membrane of the water unit, which opens the gas supply to the burners and while turning on the ignition device, which ignites the gas in the heat exchanger. If there is insufficient or excessive water pressure in the system, gas will not be supplied to the burners.
Most gas water heaters on the outside of the housing have regulators for the degree of heating and the intensity of water movement, with which the desired outlet temperature is manually set, which is displayed on the display.
For more complex devices - hot water columns of a modulating design, the adjustment is performed automatically.
Important! Adjusting the water temperature by diluting it with cold water using a mixer at the point of consumption harms the operation of the automation and leads to premature failure of the heating device.
Gas water heaters are produced with several types of ignition devices - powered by a 220 V household network, hydro generator, batteries or piezoelectric.
Of these types, the least reliable is a battery-powered device due to the unpredictability of their resource.
For emergency shutdown of the water heater, a special key is provided on the geyser.
Gas combustion products are discharged from the chamber through the outlet pipe into the chimney in compliance with safety rules.
Atmospheric geysers are the most common in everyday life - equipped with open-type combustion chambers, oxygen into which is supplied with air from the room.
More advanced, but more complex, are water-heating devices with a closed combustion chamber using outside air, which is pumped by an additional fan through a coaxial chimney - a double-acting pipe with opposite gas flows. However, such units have a significant drawback - electrical dependence, since the fan is powered by a household power supply.
How to choose a geyser
When buying this water heater, it is difficult to focus on its power, so you need to choose a column according to performance - it is indicated in the product passport and is measured in l / min (liter per minute) when the water is heated by 25 degrees. The higher this indicator, the more points of water intake with a working column will be able to work simultaneously. For example, a device with a capacity of 10 l / min is able to provide one consumer.
With a limited budget and frequent power outages, it would be advisable to choose an atmospheric water heater with a non-volatile ignition system powered by batteries or a piezoelectric element. High-quality batteries, such as Energizer or Duracell, will ensure the operation of the speaker for 2-3 months.
If the apartment does not have a chimney shaft, the chimney of the device can be brought out through the wall or transom of the window sash. With an open type combustion chamber, the pipe can be ordinary, with a closed chamber - coaxial, and the column - turbocharged, with a fan.
Important! In the absence of a chimney channel, it is forbidden to remove smoke into the ventilation shaft!
When the water supply networks are worn out, the purchase of a gas column with an ignition device from a hydrogenerator is not advisable due to its vulnerability to water hammer.
To neutralize this factor, you will have to additionally install a gearbox.
Important! A constantly burning igniter of outdated models of dispensers, following the results of several months of operation, gives a tangible increase in fuel consumption and, in addition, destroys the front wall of the heat exchanger. Therefore, the purchase of such gas water heaters should be abandoned.
Electric water heater
The stationary flow-through electric heating unit consists of a tank, in which, depending on the volume, one or more powerful heating elements are mounted. The heating of water occurs from its contact with the heater during the passage of this tank.
The performance of most of these devices is from two to four liters per minute, therefore, they provide an average temperature of water to the tap of one consumer, for example, a sink or a shower spray.
But electric instantaneous heaters are produced with a higher power, consuming a current of 380 V and capable of providing several consumer points with hot water.
Stationary flow type electric water heaters are convenient due to their compactness and ease of use, but heating elements of 3-10 kW require an individual line to be connected and cause increased energy consumption of these heaters.
Electric instantaneous water heater-faucet
A variety of electric flow-type water heaters are water heaters that combine a water tap and a device for heating water.
Such a device is mounted on a sink and connected to the water supply. The water heater is powered by 220 V.
The principle of operation is based on heating water while passing through the body of the water heater, in which the heating element is located. The heater turns on automatically when the tap is opened and, due to the small internal volume of the body and the high power of the heating element, the water heats up almost instantly - after 3-4 seconds after turning it on, it is already warm at the outlet.
The water temperature is regulated by the intensity of its passage through the device, the adjustment range is 40-60 degrees.
Such devices are also popular due to their compactness and ease of use, but a powerful heating element (3-3.5 kW) requires a separate electrical wiring line.
Storage water heating devices
Water-heating units of the accumulative principle of operation differ from flow-through ones by the presence in the body of a container of a certain volume, in which there is hot water, which is heated as it cools down or cold water arrives instead of hot water consumed. To slow down the cooling of water, the tank is equipped with thermal insulation, which saves fuel and the life of the heater. In addition to the water tank, the housing contains a heating device and security devices.
Accumulative water heating devices are produced by gas and electric.
Gas storage units
The device, also called a boiler, consists of a tank with a capacity of 50-300 liters with a built-in heat exchanger in which gas is burned. The products of fuel combustion are removed from the heat exchanger through the gas outlet pipe.
Filling the boiler with water occurs automatically, as it is consumed. The supply of cold water to the tank turns on the flow of gas to the burners, the gas supply to the burners and their ignition are turned on. The heat flow from gas combustion is directed to a turbulator - a pipe element of a special design, through the walls of which water is heated as a by-product. After heating the water to the pressure set on the temperature controller, the temperature sensor cuts off the gas supply, and the burners go out.
Storage boilers, like gas water heaters, differ in the type of combustion chamber (open, closed) and the power source of the automatic ignition device (batteries, piezoelectric element, household power supply). The advantages and disadvantages regarding these components on gas water heaters are also relevant for boilers.
Most models of boilers, due to their significant dimensions and weight, are made in the floor version. But devices with a relatively small capacity (50-100 l) installed on walls are quite heavy and require a sufficient margin of safety from the base.
How to choose a gas boiler
When choosing a storage-type water heater, you need to know the average daily consumption of hot water per family. Statistics and analysis show that the daily consumption of hot water by one person is in the range of 50 to 70 liters. By multiplying this value by the number of family members, the total daily consumption is obtained, taking into account the fact that hot water, depending on the time of year and purpose, is diluted with cold water to varying degrees when used.
In practice, the optimal volume of the boiler for installation in your own home should be 150-200 liters, with a large family with small children living - and more than two hundred.
The power of gas hot water boilers starts from 4 kW, a device with a tank volume of 150 liters is equipped with burners with a power of 7 kW - based on heating the full tank for an hour.
The ideal tank material is stainless steel, but such models are expensive. The price of boilers with a black steel tank with an internal protective coating (enamel, glass porcelain, titanium) is lower, but, unfortunately, their quality cannot be tested. Hence the conclusion - you need to buy a boiler from a well-known manufacturer, and it will be useful to get the opinion of the repairmen of these units in your city.
Electric storage water heaters
The unit, like the gas device, is a steel tank placed in a slightly larger case. Thermal insulation is arranged between the walls of the tank and the body, like a thermos. A heating element with a thermostat and two pipes are installed in the lower part of the tank - an inlet for cold water and an outlet for hot.
The device is connected to the water supply by flexible hoses with threaded connections at the ends and filled with water by opening a hot water tap on the sink mixer. When the heater is connected to the network, the water in it is heated by the heating element to the temperature set manually on the thermostat - 50-85 degrees, after which the temperature sensor turns off the heating. The operation of the heater will automatically resume after the start of hot water consumption, when cold water enters the tank instead, or after the temperature in the tank drops by 2 degrees.
According to the method of water supply, electric storage boilers are divided into pressure and non-pressure.
A pressure-type boiler cuts into the DHW system in such a way that when a hot water tap is opened on the mixer, cold water begins to flow into the tank. The reservoir of the pressure boiler is sealed, so the pressure of cold water in the system squeezes hot water out of the tank and is fed to the tap - hot water is taken from the upper layers in such devices.
The advantage of pressure-type water-heating units is the ability to use one device to provide hot water to all points of the DHW system, albeit not at the same time - if you open several taps, the water in them will not be warm enough at the outlet.
Disadvantages of pressure boilers:
- the accumulation of sediment in the tank and the need for periodic cleaning of the tank, the sediment not only worsens the quality of the water, but also aggravates the deposition of scale on the heating element;
- the water in the tank of the pressurized water heater is locked between the sink mixer and the non-return valve, which prevents hot water from leaving the riser, and therefore is under pressure; when water is shut off in the central water supply system, the boiler tank is partially emptied (up to 20% of the volume), and a vacuum will be created inside it - these pressure drops cause cracking on the inner protective coating of the tank;
- the non-return valve has a bypass device in its design, which gives off hot water to the riser with a dangerous increase in pressure from heating - part of the electricity is wasted;
- a more time-consuming procedure for replacing the magnesium anode, which prevents corrosion of the tank.
Non-pressure boiler
The device of non-pressure type water heaters is much simpler. In fact, this is a container with a lid, equipped with a float-type valve, in which a heating element with a thermostat is also mounted - water is heated to a temperature previously set on the thermostat manually. The tank is most often made of polypropylene, the tank capacity can be from 5 to 100 liters or more.
The tank of a non-pressure heater is not sealed from above, the water in it is not under pressure, and therefore, for it to enter the system, the device must be located on a hill. With a sufficient volume of the water tank, a non-pressure unit can also serve 2-3 water intake points.
Non-pressure devices are an outdated type of housing equipment with a hot water supply system, but as a source of hot water for a summer residence or just for a shower in an apartment, it is quite suitable.
The use of these devices is also justified in plumbing systems with water supply by pumps that turn on when the tap is opened.
Advantages of non-pressure units:
- tank durability;
- availability of the price range;
- ease of installation.
Flaws:
- limited performance and pressure;
- the presence of an overflow factor in case of failure of the float device.
Water heaters of flow-accumulative type
Flow-accumulative water heating units are essentially a combination of flow-through heating devices and storage devices. The unit is based on a container of a certain volume and a high-power heating element, contacting with which the moving stream of water entering the tank quickly heats up.
In the simplest models of electric heaters of this type, a non-pressure circuit is used, in more complex models, a standard pressure circuit is used.
The main advantage of the units of the flow-accumulative design is the presence in them of water heated already when it enters the tank, that is, the high performance of the device.
The capacity of most of these water heaters is 10-50 liters, some models are equipped with mixers, but more powerful devices are also produced, for example, units of the Gorenje GBK line with a capacity of 80 to 200 liters.
Advantages of flow-accumulative water heaters:
- the combination of the advantages of the two water-heating devices taken as the basis neutralizes their shortcomings;
- compactness of most models;
- turning on the flow mode when the water in the tank cools quickly brings the device into operation;
- with non-pressure performance - a good option for a shower room or a summer residence.
Flaws:
- higher cost;
- the complexity of models with several heating elements in the design;
- the dependence of the outlet water temperature on its parameters in the water supply system.
Conclusion
The choice of a water-heating unit depends on many factors, and the degree of conformity of the functionality of the device to the operating conditions is of great importance. The choice of expensive equipment in a certain situation may turn out to be a wrong decision, therefore, when buying, you must first of all proceed from the characteristics of the water heater, but without discounting the reputation of the manufacturer.
The main essence of the article
- Fresh water heaters are household appliances that justify their use even in houses with a centralized hot water system.
- For the correct choice of a water heating unit, it is necessary to know all the requirements for this equipment, since the gas or electricity consumed by them are factors of increased danger.
- The variety of types and models of household water heating equipment provides the maximum rationality of the purchase only when the technical characteristics of the proposed devices and their potential are known.
- When choosing a water heater for a home, it is necessary to take into account not only its advantages, but also its disadvantages, which in some cases can play a decisive role.
- The cost factor of water heaters is not a priority when choosing - the functionality of individual expensive models in a certain situation may not be in demand.
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