Electric water heaters: types and characteristics
The contents
The absence of a centralized hot water supply, temporary or permanent, makes us think about alternative ways of heating. Come to the rescue of water heaters, which, when properly selected parameters successfully cope with the task. Such equipment has different sources of water heating and in some cases is equipped with a storage tank. A wide market segment in the category of water heaters is a tankless electric devices, about them and speech will go further.
Characterization and device ↑
A characteristic feature of electric instantaneous water heaters – compact dimensions. Realizing the almost instantaneous heating of the fluid, they provide the ability to adjust the temperature. Drawing Parallels with gas designs, electric water heater has a significant advantage: no need in the apartment for more engineering structures (chimney, gas distribution). Also its installation does not require obtaining permits. When compared with the cumulative electric units (boilers) – there is a significant savings of space.
The internal structure of the Assembly is not particularly difficult:
- pipe for cold water inlet;
- pipe for hot water outlet;
- Ten;
- the switch or speed control of heating temperature;
- some models rotary compressor;
- terminals for connection to the power supply;
- holes for fixing the unit to the side surface.
The water passing inside the heater wash heater and warms up. Therefore, there is a regularity – the higher the pressure, the less heat and Vice versa. In cheap models the temperature is controlled by thermostat, the improved models are equipped with timers and sensors placed on the electronic panel. Electric tankless water heaters have a large range, so before you choose any instance, you should learn characteristics of each type.
Determining the required capacity ↑
To avoid disappointment during operation will allow properly chosen power of the electric machine. This will require to define a list of actions for which it is intended and estimated water consumption. The following table will facilitate the calculations:
| Purpose | Temperature, onWith | Consumption, l/min |
| Washing dishes | 45-55 | 3-5 |
| Hand washing | 35-36 | 2-4 |
| Taking a shower | 37-40 | 4-8 |
| Bath | 8-10 |
Calculate the required power of the electric water heater is produced according to the formula:
R=Q x (T1-T2)x0,073, where
Q – the volume of water that the drive pass through (l/m);
T1 and T2 – initial and final temperature, respectively.
For clarity, consider an example with the following initial data:
- the main purpose of the electric water heater – shower, that is, minute-by-minute supply of water should be about 6 liters;
- the desired outlet temperature – 38onWith;
- the water temperature at the inlet – 18onWith (assuming it is operating only in summer).
Required power (P) is: 6 x (38-18) x0. 073=8.8 kW.
There is a simplified method for determining performance of electric device. In this case, its capacity is divided into two, the result indicates how many liters of water heated to a temperature of 35onWith, he will give over 1 min for Example, at a power of 16 kW, for 1 minute you will receive 8 litres of heated water, although the temperature is 35onWith not always acceptable. During operation of the flow heater for several points of the fence is the derived result of the required power is doubled.
Remember that when installing a powerful flow heater can be problems with the wiring. Apartment old building not designed for operation of electrical equipment, exceeding the capacity of 3.5 kW. By purchasing a unit in a modern residential building, is required to clarify the parameters of the installed electrical wiring and fuses, to avoid failure of the equipment. In the absence of the necessary power, previously held actions to strengthen the grid.
Pressure and non-pressure model ↑
All instantaneous water heaters are divided into two main types: unsaturated and saturated. The first type are the flow units that generate hot water on all taps installed in the home. The process of installation involves connection of the pipe with cold and hot water. Usually the work is done by experienced professionals. This option is tankless electric water heaters it is optimal to choose in the absence of centralized hot water supply. The range includes models with top and bottom connection. Are enabled and disabled units automatically actuating the fluid pressure.
Non-pressure electric water heaters are able to operate at low and unstable water pressure. The temperature limiter ensures the unit shutdown in case of sudden loss of pressure. It protects consumers from burns and prevents damage of the equipment. Free-flow tankless electric devices are limited in capacity to 8 kW and are operated exclusively from a single point. Therefore, for each crane will require individual water heater. Such a model is better to choose to give that power will be enough. For apartments and homes with a permanent residence such option to purchase is impractical.
Equipment appliances ↑
Choose quality tankless water heater can after careful examination of all its components. What you should pay attention:
- The heating element has protection from scale. It will prolong the smooth operation of the electric machine.
- Details of the heater in contact with the liquid must be made of copper or brass of high quality.
- The housing has ground to avoid hitting people with electrodes.
- The quality of the material from which made the shower heads and faucets flow water heater. A sufficient number of small holes contribute to a comfortable shower even in low pressure. Otherwise the stream will not be effectively sprayed.
Control type ↑
The operation of the flow heater is carried out by the control system, which is presented in two versions: hydraulic or electronic. What’s the difference? Budget models instantaneous water heaters with hydraulic control, allowing one run on two power modes depending on the pressure. When the valve is closed the electric unit switches to «off». Models of water heaters that consume up to 6 kW/h, provide only a single-stage power. When there is insufficient pressure instantaneous water heaters with hydraulic control includes not always. The threshold depends on the functioning of the manufacturer and is different in different models.
The disadvantages of tankless electric devices, with hydraulic control is a lack of ability to maintain the temperature at the same level of protection against ingress of air to change smoothly the power is impossible. To exploit them is preferable in small rooms with a single point fence. If the power flow heater does not reach the threshold of 9 kW, and it will provide several points, temperature fluctuations can not be avoided.
At a higher level of functioning are electric water heaters with electronic control. Sensors and microprocessors that are installed in the electric device, allow you to change the amount of heat and pressure, the regulation is in automatic mode. Electronic control instantaneous water heaters available in two versions. There are models, which is configured exclusively by the temperature. The improved electric units have the ability to adjust the temperature and water pressure.
After reviewing the order of calculation of the required power, the characteristics of unsaturated and saturated models, the type of management to choose a tankless water heater will be.