Instantaneous electric water heater for a shower: types, selection tips and an overview of the best manufacturers

To solve the problem of constant hot water supply in the bathroom, the easiest way is to install a flowing electric water heater in the shower. It has significant advantages over the storage device, which we will examine in detail in this article. And let's pay attention to the minuses, the main one is the need for a special approach when providing electricity.

Also in this material we will give recommendations for choosing a suitable water heater, including the calculation of sufficient power. We outline the best manufacturers of electric models, focus on installation and maintenance. Indeed, for smooth operation it is necessary not only to correctly calculate the parameters, but also to carry out the installation in a qualified manner.

Features of electric water heater

The choice of a water heater for a shower between a flowing and storage type of device is not always unambiguous. Each of them has its pros and cons, and the decision in most cases depends on the ability of the power supply system.

The internal structure of the device

In bathrooms, non-pressure water heaters are installed for one collapsible point. They are designed for a single consumer, have 1-2 heating elements and rarely exceed a power of 8 kW. AND water pressuresufficient for the operation of such devices should be from 0.03 to 0.6 MPa.

The device is turned on when the flow sensor is triggered. The overheating sensor detects the temperature of the water and turns off the heating elements when it goes beyond the permissible range.

The indicator signals the user about the operation of the heating elements. If it is turned on, but water does not heat up, then this means that the heater is broken - the most common problem with instantaneous water heaters.

The Thermex instantaneous water heater does not differ from similar devices of other companies. However, when repairing, it is better to use original parts

For all water heaters, the place for connecting the hose to the water supply is indicated in blue, and for a shower head or faucet - in red

The placement of the sensors of the water flow and its overheating does not allow the heated stream to pass in the opposite direction. Therefore, for the safe operation of the device, it is necessary not to confuse the connection points of the cold water inlet and the heated outlet.

Also, for many devices, a limit on the maximum temperature of the incoming water is prescribed. As a rule, it is 30-35 degrees. If this value is exceeded, the overheating sensor will definitely work and the water heater will turn off. Therefore, you can’t connect the device to a hot riser when, according to the consumer, insufficiently heated water flows there.

The benefits of flow models

The first advantage of the flow device is its significantly smaller size. Placing it in the shower room and self-installation does not cause problems, while finding a place for a massive tank of storage water heater and its installation create significant difficulties.

The second advantage is the significantly lower cost of a domestic instantaneous water heater designed for one point of consumption. Depending on the configuration and brand, the price range of such devices is 1700 - 8000 rubles, while the price of the simplest storage water heater with a tank volume of 30 liters starts from 5000 rubles.

Maintenance and repair of storage devices must be carried out more often, but it is more expensive. In addition, not every consumer can carry out their independent installation and connection, which incurs additional costs for paying for specialist services.

When using a storage water heater, it is necessary to take into account the number of people when calculating the tank volume. However, if guests arrive, it may not be enough. The flow analog is devoid of such a disadvantage.

More criteria for comparing the flow and storage water heater we reviewed here.

Comparison of the parameters of a six-kilowatt instantaneous water heater and a fifty-liter storage device. Weight is for empty devices, not including water mass.

The problem of providing electricity

The only significant obstacle to making a decision in favor of a instantaneous water heater is the peak load on the power grid. It exceeds the performance of the storage device by several times.

Purchasing a instantaneous water heater significantly increases the requirements for an electric cable. The total power of common bathroom appliances, such as a washing machine (with a heating element 1.5 - 3.0 kW), a heated towel rail (0.4 - 0.6 kW) and a lighting line (0.1 - 0.25 kW ) rarely exceeds 4 kW.

To ensure this voltage, enough wires with a cross-section of a core of copper in 1.5 or 2.5 mm², which often lead to such premises.

Instantaneous water heater is becoming increasingly popular as a method of generating energy for heating water, independent of water supply. Therefore, when repairing a bathroom, you must immediately conduct high-quality wiring

However, the presence of a flow heater increases the maximum power consumption of the circuit to 6-10 kW and then the cable is already required with a cross section of 4 or 6 mm². This means that before installing the device, it is often necessary to replace the wiring, and it is better to separate it into a separate branch to the distribution (internal) electrical panel.

The second problem after wiring may be the load on the electrical outlet. They are marked with an indication of the permissible voltage and current strength.

Using these data, you can calculate the maximum possible power of the connected electrical appliance without the risk of damage to the outlet:

P = I * U

Where:

• P - power of equipment (Watt);
• I - current strength (Ampere);
• U - network voltage (Volt).

Household sockets for a network with a standard voltage of 220 volts have an allowable current strength of 5, 10 and 16 amperes. Therefore, devices with a maximum consumption of 1100, 2200 and 3520 watts, respectively, can be connected to them. If a heater of greater power is used, then it is necessary to install power sockets.

They have the following standard parameters:

• 25 amperes (power of the connected device up to 5.5 kW);
• 32 amperes (up to 7.0 kW);
• 63 amperes (up to 13.8 kW);
• 125 amperes (up to 27.5 kW).

In case of difficulties in installing the power outlet, you can connect the power cable to the terminal block. However, only a professional electrician should perform this procedure, as in the event of unskilled work, the connection may overheat and cause a short circuit. In a room with high humidity, this cannot be allowed.

A power outlet and plug are often included in the delivery of energy-intensive equipment. They can also be purchased at almost any store selling electrics.

If the existing electrical supply of the bathroom allows the alternate use of energy-intensive devices, then you can stop at this option. To exclude their simultaneous inclusion due to forgetfulness, it is enough to use one socket for two devices for this.

The last problem may be the maximum connected load of an apartment or house when connected to a common energy infrastructure. For gardening and private houses with old power lines, it can be only 4-6 kW.

Then you can use a flow-type water heater only if almost all other devices are turned off. But even with standard 15 kW of permitted power, it is necessary to calculate the peak load.

What to look for when choosing a water heater?

First of all, the choice of instantaneous water heater must be carried out taking into account the sufficiency of its power, and then pay attention to the brand. When buying a device of a widespread series of a well-known manufacturer, you can be sure of its quick repair in case of breakdown. This is facilitated by the availability of spare parts and the experience of troubleshooting common problems.

Calculation of the optimal power of the device

The relationship between the power of the electric water heater, water flow and the increase in temperature of the water flow is calculated as follows:

P = 0.073 * Q * (T₁ - T₂)

Where:

• P - device power (kW);
• Q - water consumption (l / m);
• T₁ - outlet flow temperature (° C);
• T₂ - inlet flow temperature (° C).

Thus, the outlet water temperature can be calculated as follows:

T₁ = T₂ + 13.7 * P / Q

The temperature of the incoming water from its own well practically does not change during the year. Its value can be measured, it is usually 8-12 degrees. The temperature value for centralized cold water supply is more dependent on the time of year and ranges from 5 degrees in winter to 15 degrees in summer.

Maximum water flow can be measured experimentally. To do this, it is enough to detect the time in seconds for which you can fill a liter bottle, and then divide the number 60 by a fixed value.

The flow of water in the shower depends not only on pressure, but also on the capacity of the watering can. Therefore, when experimenting, it is better to use a water pass through it.

Knowing the power of the device, you can calculate the value of the flow temperature at the outlet.

You can adjust it as follows:

• with a decrease in pressure with a tap, the temperature of the water rises;
• when the power of the heater decreases, it decreases.

For most people, a comfortable range when taking a shower is from 35 to 42 degrees. In order to be able to flexibly adjust the flow parameters, it is better to use a water heater with several power modes.

It is also important for centralized water supply, as it may be time-consuming. decrease in water pressure as a result of repair work on highways. In this case, the device operating at maximum power will produce a stream hotter than required.

The main reason for the pressure drop in the water supply is to carry out repair work, which can last a long time. Therefore, water heaters with reduced power modes are in demand on the market

As an example, consider a standard apartment with centralized water supply. The temperature of cold water in winter is 5 degrees, in summer - 15 degrees. Maximum jet head slightly over 4 l / m. The desired pressure for showering is at least 3 l / m. Comfortable temperature range - from 35 to 40 degrees.

P_{in winter} = 0.073 * 3 * (35 - 5) = 6.6 kW.

P_{in summer} = 0.073 * 4 * (37 - 15) = 6.4 kW.

Thus, it is necessary to purchase a water heater with a total power of heating elements of about 6.5 kW. If periodically there is a decrease in pressure in the water supply network, then you need a device with the shutdown functions of one of the heating elements.

Popular series of famous manufacturers

Almost all well-known manufacturers of instantaneous electric water heaters offer the same model range of devices.

This is due to the standard pressure in the water supply and approximately the same parameters of the water flow, which contribute to a comfortable shower.

Electric water heaters are sold in many stores. In addition to technical parameters and prices, you must pay attention to the warranty and the location of the service center

Series Smartfix 2.0. Swedish manufacturer Electrolux represented by three devices equipped with two heating elements with the following maximum power:

• 3.5 (1.5 + 2.0) kW;
• 5.5 (2.2 + 3.3) kW;
• 6.5 (3.0 + 3.5) kW.

Availability of letters “T” at the end of the device name means a complete set with a crane, and “S” - shower head. They are connected through a standard 1/2 inch connector, so existing nozzles can be used. Assembly is carried out in China and Russia.

Series Stream Italian manufacturer Thermex represented by three devices with maximum power limits of 3.5; 5.0 and 7.0 kW. Water heaters also have two heating elements. Russian assembly, lower price range.

Series Whell Swedish manufacturer of water heating equipment Timberk also represented by three models with a maximum power of 3.5; 5.5 and 6.5 kW. There is a restriction on the minimum allowable temperature of the water flow at the inlet (16 degrees), although, according to reviews, the device works well at lower values. Chinese production.

Series H-IWR Korean manufacturer Hyundai represented by three models with maximum power parameters of 3.5; 5.5 and 6.5 kW. Buyers notice the smell of plastic, which disappears after a while (Chinese production).

The widespread series of water heaters presented above have a bottom eyeliner and are intended for use in bathrooms. All devices of the same model range have the same design and construction, differing only in the power of the heating elements.

The rating of the best models of flowing water heaters, compiled by popularity among buyers and positive reviews, we gave in next article.

Nuances of connection and operation

For trouble-free operation of the instantaneous water heater, it will be necessary to study the principle of its operation and know the main technical characteristics of the device. There are also nuances of connection and maintenance that will help to avoid problems during its operation.

How to connect a water heater?

There are water heaters with bottom, top and side water inlet.In bathrooms, as a rule, use the lower option. It is necessary to determine the optimal connection method before purchasing the device, since it is forbidden to install it in a different position.

There are two ways to connect to cold water:

• to the shower connector of the tap-shower switch;
• directly to the cold branch of the water supply.

The first method leaves it possible to use a standard water tap to produce cold water, bypassing the water heater.

In a user-designed plumbing system, valves must not be used after the instantaneous water heater. Otherwise, it will cause it to overheat even if there is a trip function by the temperature sensor. Such a rule is directly indicated in the instructions for many devices.

A typical option for connecting a flow device to a cold water system. The shower switch and the tap are located up to the water heater, and after it the flow is free

According to the electrical safety requirements for hygiene GOST R 50571.7.701-2013sockets for voltage 220 volts in the bathrooms must be installed in the third zone (further in the plan than 60 cm from the shower, bathtub or sink faucet) and comply with the degree of protection IPX4 or higher.

At a distance of more than 3 meters from the water supply points, ordinary class sockets can be installed IPX1.

Despite the fact that the instantaneous water heater is designed for humid rooms and has good tightness, it is necessary to take into account the undesirability of a direct stream of hot water when choosing the installation location. Thus, the case is heated, which will negatively affect the density of connections and the operability of the control panel. In addition, the ingress of water reduces the strength of fixing the device to the wall.

Fastening to the wall is carried out by standard methods using screws. The weight of the device is from 1 to 3 kg, therefore, to take any measures for reinforced installation is not required. Some owners do without fixing the device, but this does not need to be done, as there is a risk of the device falling and depressurizing during its operation, which is dangerous for people in the room.

Do you want to do the installation of a running water heater on your own? We recommend that you familiarize yourself with step by step instructions on installation.

If it is not possible to install a water heater outside the bathtub or shower, then it should be placed as high as possible. In this case, the amount of water falling on it will decrease.

Recommendations for operation and maintenance

In addition to wiping the surface of the water heater with soapy water, periodic maintenance consists of changing the filter installed on the cold water supply.

To do this, the following actions are performed:

• disconnect the device from power;
• close the tap on the water supply;
• unscrew the hose;
• remove and rinse the strainer;
• reassemble the device in reverse order.

For trouble-free operation, it is important to properly configure the equipment.

The water temperature must be adjusted in the following order:

1. Open the tap and wait for the water to pour out of the water heater.
2. Turn on the water heater. After 10 seconds, the temperature will become constant.
3. If the temperature is not suitable for taking a shower, then by adjusting the pressure and operating modes of the water heater, change it.

After each action to change the water supply pressure or the power of the heating elements, it is necessary to wait 10-15 seconds to establish constant temperature values.

Detailed instructions for the operation and maintenance of the water heater we provided in this article.

Conclusions and useful video on the topic

Mounting to the wall, connecting the liner and starting the Electrolux Smartfix water heater:

An example of improper use of a water heater. The device is not fixed, the tap is installed after hot water emerges:

Calculation of the required power of the instantaneous water heater, its fastening and connection to the water supply can be done independently. The greatest difficulty is the safe provision of the device with electricity. Choosing a well-known manufacturer will provide a quick solution to problems in the event of a device breakdown..

You want to ensure the year-round presence of warm water in the shower by installing a flow-through model of a water heater, but friends convince you of the inefficiency of such a solution? Ask your questions under this article - the real owners of instantaneous water heaters will share their experience with you and your own opinion on the advisability of installing it.