Installation of a water heater for a sink. Pros and cons of boilers and flow models. Selection and installation of storage devices. Price of water heaters for washing and installation costs.
The under-sink water heater is a compact stand-alone device for heating a small volume of liquid. It is used for household needs and is installed in the kitchen. We will talk about the types of water heaters for washing and their installation in this article.
Water heater device for sink
In the photo there is a water heater for a sink
Sink water heaters differ from other similar devices in small dimensions. Appliances are made small to fit in a kitchen cabinet or under a bathroom sink.
Products are of two types - storage and flow. Despite the difference in design, they all function according to the same principle: under the action of an electric current, the conductor heats up and transfers heat to the water.
There may be several reasons to install a water heater under the sink:
- With a seasonal shutdown of the city hot water system for repair or maintenance.
- When repairing plumbing in a separate house.
- If desired, place the device in an inconspicuous place.
- For heating a small volume of liquid. If a lot of hot water is required, a standard high-power instantaneous boiler is installed.
- To provide hot water to points located far from each other. In this case, the products are installed under each sink.
Storage water heater device for sink
Storage water heaters for washing can be easily distinguished from other small-sized devices of a similar purpose by the location of the pipes for supplying cold and taking hot water - they are always located in the upper part of the product. When buying a device, be sure to pay attention to this. Small-sized storage models with a bottom arrangement of supply pipes are not intended for installation under a sink. They will not work reliably and quickly fail.
Boilers for washing, regardless of the volume of the storage tank, consist of the same elements:
- External tank … All parts of the device are located inside it. Brackets for wall mounting are welded to it. The shape and external design of the tank determine the appearance of the water heater.
- Inner tank … In it, water is heated and stored until used. The tank contains heating elements and devices that control the operation of the water heater under the sink.
- Thermal insulation … A layer of insulating material between the outer and inner tanks to reduce the cooling rate of the liquid.
- Heating elements … Details in which the conversion of electrical energy into heat occurs.
- Cold and hot water intake flanges … For connecting pipes of a domestic water supply system.
- Divider … A special casing in the inner tank, which ensures a uniform supply of cold liquid throughout the entire volume of the water heater under the sink.
- Thermostat … A device for adjusting the temperature in the storage device by changing the current strength.
- Thermometer … A device for monitoring the temperature of the liquid at the outlet from the tank.
- Magnesium anode … The part reduces the intensity of corrosion of metal elements.
- Control system … Consists of a control panel with buttons and levers, sensors and devices that ensure the automatic operation of the water heater under the sink.
- Protection system … Special devices that disconnect the product from electricity to prevent emergencies.
For ease of use, devices are often equipped with additional functions:
- Water heating control … The product has the ability to adjust the limiting temperature of the liquid. This function is useful for families with children.
- Rapid heating … Boilers with two heating elements have this property. Allows to reduce the heating time of water.
- Splash proof … If it is available, the safety of the water heater under the sink is increased. The degree of safety is indicated by numbers from "0" to "8". The maximum value indicates that the instrument is drip-proof from all directions.
- overheat protection … The device contains sensors configured for the maximum permissible temperature for this model.
- Frost protection … The function is useful when using a water heater for a sink in summer cottages without heating. Maintains the temperature in the drive at +5 degrees, preventing it from freezing.
- Dry start protection … The sensors block the supply of current to the heating elements if the tank is empty.
- Overvoltage protection … Prevents damage to electronic equipment due to power surges.
- Safety valve … Bleeds water from the tank if the pressure is too high.
- Control equipment … Finds malfunctions in the operation of the device and outputs a signal to the control panel.
- Self-cleaning … Prevents the formation of deposits on the walls of the tanks and increases the service life of heating elements.
- Antilegionella … A special mode of a water heater for washing, in which the liquid is heated up to +65 degrees to fight microorganisms.
- Smart mode … When the function is enabled, the device analyzes the frequency of starts and the temperature of the used water, independently determines the time and mode of operation of the device.
- Work according to a given program … If you have the appropriate equipment, a water heater for a sink can be set to work at a certain period of time.
- Remote control … The kit includes a remote control for controlling the device, which is located far from the crane.
- Display … Shows the current parameters of the product or displays information about malfunctions.
- Filter … Retains solid impurities at the entrance to the device.
- Wi-Fi … The function allows you to control the operation of the water heater under the sink via the Internet.
A storage water heater for a sink works as follows:
- The tank is filled with water from the mains. The thermostat is set to the desired temperature.
- After being connected to the network, the heating elements heat up and increase the water temperature. Warm liquid rises to the top of the tank and accumulates there.
- After opening the supply valve, the pressure in the tank decreases, the cold liquid begins to squeeze out the heated one into the line through the pipe in the upper part of the water heater under the sink. Without pressure in the supply line, hot water does not flow out of the boiler.
- With prolonged use of the device, the temperature in the storage device decreases. If the difference between the actual water temperature and the set one reaches 3 degrees, the sensor automatically connects the heating elements to the mains.
- After closing the supply valve, the heating elements continue to function until the temperature set on the thermostat is reached.
Instantaneous water heater device for sink
Instantaneous water heaters under the sink are distinguished by very fast water heating. After turning on the device, the result appears after 10-15 seconds. There are no dedicated under-sink models. For these purposes, you can use any models of low or medium power that fit in the cabinet. In the kitchen, where a small consumption of liquid is required, 3-5 kW products are installed, in the bathroom - up to 12 kW.
Instantaneous water heater for sink, consists of the following parts:
- Outer casing with decorative coating … Serves for placing the elements of the product.
- Heat exchange tube … Heat is released through it.
- Heating element … An element that heats up when an electric current passes through it. It is placed in a metal flask or heat exchange tube.
- Flow sensor … It turns on or off as a result of a change in water pressure at the inlet to the water heater under the sink.
- Electromagnetic starter … Used in high power products.
- Thermostat … A device for adjusting the temperature of the liquid depending on the pressure of the water in the system.
- Thermometer … Shows the temperature of the liquid at the outlet of the water heater under the sink.
- Thermal fuse … Stops the operation of the device if the temperature reaches 65 degrees.
The design may include additional elements to protect against breakdowns and increase functionality (like boilers).
The principle of operation of an instantaneous electric water heater for a sink is as follows:
- The product will automatically start working after turning on the supply tap when there is pressure in the water supply. The liquid pressure must be strong enough to close the contacts for transmitting a signal to connect the device to the electrical network.
- Powerful heating elements heat up and heat the water flow. The temperature is limited by a thermostat with a preset value. If the tap is screwed on, the thermostat will limit the amperage for the heating elements and reduce the intensity of their heating.
- After the valve is completely closed, the device will automatically stop working.
Advantages and disadvantages of water heaters for washing
Accumulative and instantaneous water heaters for washing are produced in a wide range, therefore, when choosing, it is necessary to take into account their advantages and disadvantages.
Small boilers have always been popular among users due to the following advantages:
- The device is equipped with heating elements of low power (1.5-2 kW), so it is allowed to connect it to an ordinary outlet, like an electric kettle. Devices are often installed in summer cottages or in other places with low-power electrical networks.
- The product does not require a lot of pressure in the water supply to function. For the liquid to flow to the place of consumption, 2 atm is enough.
- The price of a water heater for a sink is low and available to consumers with any income.
- The product is small and easy to place in a cabinet.
- The water in the tank remains warm for a long time, which allows you to use it at any time without turning on the device.
- If used correctly, the device works properly for 10-15 years.
Boilers for washing have a number of disadvantages:
- The storage tank is small, so you need to use the device sparingly.
- Despite its small size, the product is not capable of instantly heating water.
- The device needs constant maintenance. Hard deposits are deposited on the heating elements, which reduce the efficiency of the product. Therefore, it is recommended to change them every 3-4 years.
- In boilers, the entire volume of water is heated under the sink. Often this amount is not required for one procedure.
- The device consumes electricity even when the taps are closed.
Instantaneous water heaters for washing are structurally different from boilers and have a number of advantages over them. The undoubted advantages include the following:
- Small dimensions of the device. Low-power products are comparable in size to a shoebox, so there is always room for them under the sink.
- Instant heating. After turning on the device, warm liquid from the tap will flow in 15-20 seconds.
- An instantaneous water heater for a sink provides consumers with an unlimited amount of warm water. High-power appliances can be connected to the kitchen tap and to the shower head at the same time.
- The design contains only non-ferrous metal parts that are not afraid of corrosion.
- Installation of an instantaneous water heater for the kitchen under the sink is very simple and does not require experience in such work.
- The product heats only the amount of liquid that the consumer needs at the moment.
A flow-through water heater for a sink has a number of significant disadvantages:
- The heating elements of the device are very powerful (at least 3 kW), and not all electrical wiring is capable of withstanding a heavy load. To ensure safe operation of the mechanism, it is necessary to lead a separate cable from the switchboard to the device.
- The product does not heat the liquid above +60 degrees.
- The device works only if there is a sufficiently high pressure in the line (at least 2 atm.). With a small pressure, it will not turn on.
- Products for washing are low-power, and there may not be enough hot water for other hot water points.
How to choose a water heater for a sink?
Wash water heaters are used for technical purposes - washing dishes, washing, connecting to a dishwasher, etc. The products can also be used for morning procedures and even for taking a shower. Storage water heaters for sinks are available in a large assortment, which allows users to choose the best appliance for a particular place. In order for the product to work for a long time and with maximum efficiency, carefully study some of the characteristics.
Water heater power for sink
This characteristic is important first of all when choosing a boiler: the electricity bill for using the device depends on it. A good device consumes no more than 1 kW per day. If you need a little hot water, for example, for washing dishes, the compact product can handle the task easily.
But using it for bathing is impractical: no one wants to control the flow of fluid. Therefore, with a high flow rate, the best option would be an instantaneous water heater for a sink with a capacity of at least 8 kW. Usually, such devices are three-phase, it is advisable to install them in apartments with electric stoves operating from a voltage of 380 V. Thus, you can save on laying the power cable from the panel to the product.
If the apartment does not have stationary electric stoves, and the standard electrical wiring is weak, give up the flow heater and buy a storage water heater for a 30 liter sink. This is the largest model that fits under the sink.
To find out how long it will take for your boiler to heat up the contents of the tank, use the table:
| Water heater power for sink, kW | Water heating time up to 65 ° C, min. | |||
| Tank volume, l | ||||
| 5 | 10 | 15 | 30 | |
| 1 | 20 | 36 | 55 | 110 |
| 2 | 10 | 20 | 27 | 55 |
| 3 | 6 | 12 | 20 | 36 |
| 4 | 4 | 9 | 14 | 27 |
The dependence of the field of application of the instantaneous water heater for washing on the power of heating elements is shown in the table:
| Model | Number of users | Productivity, l / min. | power, kWt | Procedures |
| AEG MP 6 | 2 adults | 2-4 | 6 | Hand washing |
| Stiebel Eltron DHC 8 | 2 adults + 1 child | 4 | 8 | Dishwashing |
| Stiebel Eltron DHF 12 C1 | 4 adults | 5 | 12 | Dishwashing |
Water heater tank material for sink
Water has a different composition, and when it is heated in the tank, chemical processes can occur that negatively affect the functioning of the device. Therefore, when choosing a water heater for a sink, it is necessary to find out what the storage tank is made of. The tanks are made from metal sheets 1, 75-2 mm. When used correctly, such dimensions provide a product service life of up to 14-15 years.
The way to protect the box from corrosion has a great influence on the durability of the device. In its complete absence, walls of any thickness will rust in 3-4 years. The metal parts of the water heater under the sink are protected from corrosion in two ways - a protective coating and active protection. Enamel, silver or titanium sputtering, glass ceramics, etc. are used as a protective coating. Active protection consists in the presence of a magnesium anode, which has a high negative electrode potential, which acts as a cathode. During the operation of the mechanism, it is he who will be destroyed, and not the walls.
The most common material from which a tank for a water heater is made for a sink is galvanized steel. To prevent the metal from rusting, it is coated in various ways.
- Enamel coating … Substances are added to the enamel that give it the properties of stainless steel. It expands with the metal, has the same coefficient of thermal expansion, adheres reliably to the surface and "stretches" with the metal when heated. The enamel has scale repelling properties. Over time, layers will still appear on the walls of the tank, but it will not be difficult to remove it. Among the shortcomings, one can note the fragility of the protective layer, which sometimes peels off after a strong blow.
- Silver plated … Such containers have good antibacterial and anticorrosive properties.
- Titanium plated … Increases resistance to high temperatures and ensures uniform heating of the tank.
Unreliable anti-corrosion coatings include a polymer film. Glass phosphorus and glass ceramics are slightly better, but they also crack when the temperature drops, and signs of corrosion appear on the tanks. Glass enamel will reliably protect the container for 3 years, but then it will also be covered with cracks.
The reliable material for the drives is stainless steel. Products made from it do not corrode, they are not afraid of a sharp temperature drop, even if the device is accidentally turned on without water, nothing will happen to it (except for the heating element burns out). The service life of water heaters for washing reaches 10 years. The weak point of stainless steel drives is the weld, on which rust can appear, but many manufacturers (Ariston, Willer, Electrolux) have learned how to fix the problem with the help of passive protection, which greatly increases the life of the water heater under the sink. Products with a stainless steel tank are more expensive than those made of regular enamelled steel, but the difference is only noticeable on inexpensive models.
Sizes of water heaters for sink
The dimensions of the water heater for the sink are the first characteristic that the user looks at. The applicability of the device depends on them. The best option for the kitchen are storage devices (boilers) with a capacity of 5-30 liters.
When choosing a boiler by size, use the following information:
- For washing dishes, 5-15 liters of water is enough, depending on its amount.
- To wash your hands and perform morning procedures, you need 5-8 liters per person.
- A 10 liter sink water heater is enough to consistently wash the dishes and wash alone.
- Water heaters for a sink for 15 liters are bought for a family of 3 people, but with austerity conditions.
- For bathing a family of 4, you will need a device with a volume of 16-30 liters.
- Products of small capacity (5-15 liters) are placed under any sink, next to the trash can. Models with a volume of 25-30 liters take up all the space under the sink and do not leave any free space. For placement in the cabinet of the device, it is sometimes increased. There are other options for solving the problem of insufficient space for installing a water heater under the sink, for example, selecting the shape of the device. The outer case of the product can be round, narrow, faceted, flat. Round ones fit in standard sizes. Flat ones have a shallow depth. Faceted are available with rounded edges. Often the problem is solved by purchasing a product with vertical or horizontal mounting.
- The overall dimensions of a water heater for a sink depend not only on the volume of the storage tank. If the sizes of products with the same storage device differ, choose a larger one - it has a thicker thermal insulation layer. For different models, the insulator can be 15-42 mm. The more massive it is, the more noticeable the energy savings. Increasing the thickness by 1 mm keeps the water temperature by 1, 2 degrees.
Popular water heaters for washing with minimal dimensions (storage volume - 5-10 liters) are shown in the table:
| Boiler model | Dimensions, w-h-d | Storage capacity, l | Ten | power, kWt |
| Bandini Braun A5 ST | 250x340x245 | 5 | Wet | 2 |
| Ariston Andris Lux 6 UR EU | 315x315x250 | 6 | Wet | 1, 5 |
| Eldom Extra Life 7 72324PMP | 285x340x288 | 7 | Wet | 1, 5 |
| Gorenje GT 10 U / B9 | 350x500x265 | 10 | Wet | 2 |
Water heaters for a sink with optimal dimensions (storage volume - 15-30 l):
| Model | Dimensions, w-h-d | Storage capacity, l | Ten | power, kWt |
| Zanussi ZWH / S 15 Melody U Yellow | 368x368x340 | 15 | wet | 1, 5 |
| Willer Optima Mini New PU25R | 450x450x388 | 25 | wet | 2 |
| Toshiro WSB EHU30 | 435х435х365 | 30 | wet | 1, 5 |
How to install a water heater under the sink?
Installation of the device is carried out in several stages. First, you need to prepare a place for installing the device, buy all the installation parts that are not supplied with the product, and then connect it to the water supply and to the mains.
When choosing a place for a water heater under the sink, the following requirements must be observed:
- The outside of the product must not be exposed to moisture. Make sure that all the connections of the cabinet above it are sealed and that the plumbing does not leak. If it is damp under the sink, use models with splash protection rating IP 24 and above.
- Place the device so that it is easy to switch between operating modes.
- If a product with a large tank volume does not fit under the sink, install compact models under each sink or sink in the apartment.
- In the place chosen for the installation of the boiler, nothing should interfere with the installation work.
Before connecting the water heater under the sink, check the condition of the electrical wires and the socket. Observe the following requirements:
- Boilers with a capacity of 1.5-2 kW are allowed to be connected to the general electrical network.
- For instantaneous water heaters, it is necessary to lay a separate electric cable under the sink, with a voltage of 5 kW.
- More powerful models operate on 380 V and require a three-core wire.
- For safe operation of the product, install a 10 A RCD in the electrical panel, and a 16 A automatic fuse in the line connecting the device to the panel to protect against short circuits.
- Electric water heaters under the sink must be grounded.
Many models are supplied without a connecting lead with a plug. In this case, connect the cable from the panel directly to the terminals on the device after its installation. If you have a connecting wire, select a location for the outlet near the product.
The cross-section of the supply cable, depending on the capacity of the water heater for washing, is shown in the table:
| Conductor cross-section, mm | Copper cable | |||
| Voltage, 220 V | Voltage, 380 V | |||
| current, A | power, kWt | current, A | power, kWt | |
| 1, 5 | 19 | 4, 1 | 16 | 10, 5 |
| 2, 5 | 27 | 5, 9 | 25 | 16, 5 |
| 4 | 38 | 8, 3 | 30 | 19, 8 |
| 6 | 46 | 10, 1 | 40 | 26, 4 |
Prepare special devices that ensure the safe operation of the product - a pressure regulator and a safety valve, which are called a safety group. The pressure regulator is designed to protect the boiler from water hammer.
The safety (check) valve has several functions:
- Does not include the product if the heating elements are not covered with water.
- Used to drain the tank.
- Bleeds off excess pressure in the tank. An emergency situation occurs if the thermostat breaks down and does not disconnect the product from the mains when heating to the set temperature. Without a safety valve, the tank will burst due to high internal pressure.
Installation of a water heater under the sink is carried out as follows:
- Make holes in the wall for fixing the device.
- Install the mounting bolts supplied with the product into the holes.
- Install the boiler with the brackets on the bolts.
- Screw the safety valve, pressure reducer, filter and tap with an adapter onto a plastic pipe onto the cold water inlet flange. Check the correct installation of the safety valve. The direction of the arrow on the body must match the direction of flow.
- Secure the drain tube with one side to the safety valve, and the other side into the drain.
- Screw only the shut-off valve onto the hot water connection of the product. Connect the hot fluid line to it through the adapter.
- It is not recommended to connect the water heater under the sink to the domestic mains using a flexible hose. A rigid connection is more reliable, moreover, plastic pipes have a larger diameter and do not reduce pressure.
- On the outlets of the mains to the mixer, install tees to which the pipes of cold and hot water will be connected.
- Connect the device with a tee.
- Open the cold water tap and fill the boiler.
- Open the tap on the hot line. When the contents of the tank flow out of it, the water heater under the sink is ready for use.
- Connect the product to the mains.
- Wait for warm water to come out of the tap.
- Check the pressure in the tank, which should not exceed 6 atm. This is the optimum value for a boiler. If the pressure rises, the safety valve will automatically operate and lower it.
- Disconnect the water heater under the sink from the power supply and make sure that cold water flows out of the tap after a while.
- Close the mixer tap, set the thermostat to the desired temperature and plug the device into the mains to start normal operation.
The price of installing a water heater for a sink
Any person can install a water heater under the sink, but if you do not have experience in plumbing work, it is better to invite an experienced craftsman. The cost of his services can be approximately determined independently. Installation costs consist of the cost of the product and the installation fees.
When choosing a device, keep in mind the following:
- A boiler is more expensive than instantaneous water heaters, subject to equal functionality. The price of the latter is increased by high requirements for the manufacture of flow sensors, heating elements and other elements of the device.
- The cost of the product is affected by the material of the tank. The price of enameled drives is slightly less than the stainless steel models. Tanks coated with silver and titanium ions are very expensive and are installed in elite technology.
- When choosing a water heater for a sink, give preference to well-known brands that have proven themselves well. Despite the high cost of models from reputable manufacturers, their brands guarantee the quality of products. Do not buy devices from unknown companies with a low price. this is a sign of a deviation from the manufacturing technology of parts, the use of low-quality materials or a discrepancy with the declared characteristics.
- The price of water heaters for washing is also influenced by the presence of devices that increase their functionality. The more there are, the higher the cost.
Price of storage water heaters for washing in Ukraine:
| Boiler model | Storage capacity, l | Price, UAH. |
| Bandini Braun A5 ST | 5 | 2630-2760 |
| Ariston Andris Lux 6 UR EU | 6 | 2030-2140 |
| Eldom Extra Life 7 72324PMP | 7 | 2400-2460 |
| Gorenje GT 10 U / B9 | 10 | 2630-2720 |
| Zanussi ZWH / S 15 Melody U Yellow | 15 | 2390-2510 |
| Willer Optima Mini New PU25R | 25 | 1830-1970 |
| Toshiro WSB EHU30 | 30 | 2970-3020 |
Price of storage water heaters for washing in Russia:
| Boiler model | Storage capacity, l | price, rub. |
| Bandini Braun A5 ST | 5 | 6200-6500 |
| Ariston Andris Lux 6 UR EU | 6 | 5500-5700 |
| Eldom Extra Life 7 72324PMP | 7 | 5100-5400 |
| Gorenje GT 10 U / B9 | 10 | 5900-6100 |
| Zanussi ZWH / S 15 Melody U Yellow | 15 | 4900-5200 |
| Willer Optima Mini New PU25R | 25 | 4200-4700 |
| Toshiro WSB EHU30 | 30 | 5700-5900 |
The price of instantaneous electric water heaters of various manufacturers in Ukraine:
| Manufacturer | Price, UAH. |
| Aeg | 3700-27000 |
| Electrolux | 1100-3800 |
| Timberk | 870-1400 |
| Thermex | 1200-2100 |
| Zanussi | 970-1200 |
| Stiebel Eltron | 4600-31500 |
The price of instantaneous electric water heaters from various manufacturers in Russia:
| Manufacturer | price, rub. |
| Aeg | 8000-60000 |
| Electrolux | 2500-8500 |
| Timberk | 2000-3000 |
| Thermex | 2800-4600 |
| Zanussi | 2300-2700 |
| Stiebel Eltron | 10600-63500 |
The cost of installing a water heater for a sink in the kitchen depends on the conditions of work and the type of device. Installation of flow-through products will be more expensive if you need a separate cable line from the shield to the product. It also increases installation costs in cramped working conditions.
Installation price of electric water heaters for washing in Ukraine:
| Boiler installation | Price, UAH. |
| Installation of instantaneous water heater | from 450 |
| Connecting an instantaneous water heater to the main | from 730 |
| Laying the electric cable for the instantaneous water heater | from 40 |
| Laying the electric cable for the instantaneous water heater in the box | from 60 |
| Installation of an automatic fuse in the electrical panel | from 200 |
| Installation of RCD | from 450 |
| Complete installation of the water heater | from 630 |
| Installation of a water heater up to 3.0 kW | from 470 |
| Installation of a water heater from 3.1-5.5 kW | from 520 |
| Installation of a water heater up to 6 kW | from 660 |
| Boiler installation 10-15 liters | from 870 |
| Laying pipes through a partition | from 100 |
| Installing the socket | from 100 |
| Installing the pressure reducer | from 130 |
The price of installing electric water heaters for washing in Russia:
| Boiler installation | price, rub. |
| Installation of instantaneous water heater | from 1000 |
| Connecting an instantaneous water heater to the main | from 1500 |
| Laying the electric cable for the instantaneous water heater | from 80 |
| Laying the electric cable for the instantaneous water heater in the box | from 100 |
| Installation of an automatic fuse in the electrical panel | from 450 |
| Installation of RCD | from 1000 |
| Complete installation of the water heater | from 1500 |
| Installation of a water heater up to 3.0 kW | from 1100 |
| Installation of a water heater from 3.1-5.5 kW | from 1300 |
| Installation of a water heater up to 6 kW | from 1500 |
| Boiler installation 10-15 liters | from 2000 |
| Laying pipes through a partition | from 250 |
| Installing the socket | from 250 |
| Installing the pressure reducer | from 350 |
How to install a water heater under the sink - watch the video:
It is not so difficult to independently choose and install a water heater under the sink, despite the need for plumbing and electrical work. The biggest problem is the sealed pipe connection, but the experience comes quickly. With a serious attitude to work, a new water heater will be put into operation in a few hours.
