Every year, for the longest three weeks, we all look longingly at the red faucet, which no matter how hard we turn it, doesn’t let a single drop out. But a civilized person cannot do without shower!
The first water heaters appeared, of course, in those countries where there was no centralized hot water supply. But with the appearance of the market in our country all the achievements in this area are available, and a wide range of models offered today allows everyone to choose what they need.
Armed with a small dictionary, you can, without hesitation, talk to the seller and understand the features of the models presented.
By the type of energy source used water heaters are divided into electric and gas. Due to the complexity of the installation of the gas water heater, which is possible only in apartments located no higher than the 5th floor and equipped with a chimney, in the city are mainly used by electric water heaters. That is what this article is about.
When quantity turns into quality of the two types
What could be easier than heating water in an electric kettle! Electric water heaters do the same, and the difficulties arise from the fact that it is necessary to heat not 1-2 liters, but much more: for a bath, for example, all 200.
If to boil 1 litre of water in a 2 kW kettle, it takes three minutes, which corresponds to the power consumption equal to the product of power by time, t.e. If a water heater consumes less than 0.1 kWh, heating 200 liters requires almost 200 times the energy almost – because it has to be heated to a lower temperature .
You can get this energy in two ways: either by using high power, or spending a lot of time. In accordance with this and water heaters are of two types: flow or storage.
Flow-through water heaters
Thanks to the high power of flow-through devices installed in their heating element is heated to such high temperatures that the water has time to warm up in a short period of time during which it is in contact with the heater.
So it is only necessary to open the faucet, as it pours the hot water. It is clear that the greater the flow denser the stream , the higher the power of the device must be, so that the water had time to warm up to a certain temperature.
Number of liters of water heated for 1 minute, characterizes the flow-through heater capacity, and is the main parameter, which should be considered when choosing this type of heater.
Approximately the performance can be estimated by dividing the power value by 2 when heated at 25 ° C . Depending on what we need hot water for, we use it differently. In other words, if for washing dishes or washing is quite enough jet 2-4 l min., then a normal shower is obtained at a flow rate of 5-8 l min., and it takes at least 8-10 litres of water per minute to keep the water from cooling down when filling the tub.
Consequently, for hot water supply of a washbasin or kitchen sink you need a flow heater with power of 4-7 kW, for a shower – 10-16 kW, for a bath – 16-20 kW.
However, if you expect to use the water heater only in the summer, when the water at the inlet is already heated to 12-16 degrees, a smaller capacity device will do.
Features of flow-through valves: high power – fast heating
Flow-through water heater – provides instant water heating and has no limit on the amount of hot water produced. It turns on automatically as soon as the tap is opened and turns off when the tap is closed. Compact, but to get a good flow requires power of at least 7 kW.
Capacity – the number of liters of water heated in 1 minute.
Single-phase 220/230 V/50 Hz – used for water heater power up to 12 kW. Suitable for hot water supply in urban apartments in the warm season.
Three-phase instantaneous heaters 380/400 V/50 Hz are used for capacities from 12 to 27 kW. Can supply hot water to several taps running simultaneously.
Hydraulic control – control with a flow sensor that turns on the heater when the flow reaches a certain value. The water temperature at the outlet depends on the temperature of the incoming water, the size of the flow density of the jet and the heater capacity.
Electronic control – electronic unit provides a stable water temperature regardless of the magnitude of the flow and fluctuations in temperature or pressure at the inlet.
With three phases the pressure is stronger
Flow-through water heater almost instantly heats any amount of water, that is, the hot water will flow from the tap as long as it is open.
It is also so compact that it easily fits into the smallest of spaces.
All this would make flow-through water heaters the most attractive, if not for one question – where to get the required kilowatts?
After all, all that is usually available to residents of homes with gas stoves – 2.5-3 kW, which is sufficient only for a trickle of up to 1.5 l min. Under such a stream at best you can only wash your face or dishes, and only in summer and not including other electrical appliances: washing machine, kettle, iron…
In principle, if you make a larger supply line, change the counter and put a “personal” automatic water heater, you can install a little more water, but first it is necessary to obtain permission. Is it worth the trouble??
In this respect, the owners of electric stoves are in a more advantageous position: in their houses, the maximum possible load is 5-10 kW, which allows you to provide hot water not only for sinks, but also for showers.
True, with a special nozzle with a strong spray, making the stay under a not too dense jet more comfortable. To connect the flowmeter can use the wiring for the stove, but to turn on the flowmeter and the stove will also have to only one at a time.
If you do want to install a flow-through water heater of such power that you could also soak in the bath, the tenants of old houses will have to think twice: will need a special permit for three-phase wiring, since only 380 V voltage can provide power to flow-through heaters with a capacity of over 12 kW.
But first you need to find out whether it can be done at all. But if permission is obtained, all your worries will be more than paid off: you will have hot water instantly, in any quantity, in all taps and no matter what time of year, which will allow you to refuse the services of unreliable and inflexible centralized system.
Water heaters
The storage heaters have no caveats with power supply: for a 2 kW heater is enough for 220 V, available in any socket. Exceptions are large volume storage units, which use a capacity of 4-6 kW to reduce the time of heating a large amount of water they can not be connected to a regular outlet, so you have to make your own dedicated electrical wiring.
Of course, with such power would have to wait each time for the water to heat up, but the heater is called a storage tank because it can accumulate-save pre-prepared hot water.
This is achieved through thermal insulation placed between the inner tank with water and the outer walls of the accumulator, as well as built-in thermostat device, which turns on the heater as soon as the temperature deviates from the set temperature. High-quality insulation can store heat so well that the temperature drop per hour does not exceed 0.25-0.5 ° C.
Features of storage tanks: a thermos with heating
Accumulation water heater is designed as a thermos with heating: after heating water to a temperature of 35-85 ° C maintains it in automatic mode. Can be between 5 and 1,000 liters. Runs from 220 V mains and consumes 2-4 kW.
Heat insulation – a layer of heat insulator polyurethane foam, basalt fiber of thickness 20-80 mm, placed between the inner tank and the outer case.
The corrosion control enamel is a protective coating of the inner surface of the storage tank, manufactured using a special technology.
A magnesium anode provides additional corrosion protection. Because of the gradual “dissolution” magnesium anode must be replaced regularly lifetime, depending on quality and size – from 1 to 7 years .
The active anode detoxifies corrosive substances electrochemically. Does not require replacement, but needs a constant power supply.
Heating element – can be open spiral or closed TEN . Thin coil – little inertia, any change in the heating mode instantly affects the water temperature.
On the coil almost no scale is deposited, the water heater with such a heater can also be operated in hard water. But the presence of air pockets can be fatal for the coil. Closed heating element is more reliable in operation, and it is not afraid of airlocks. But it has to be regularly descaled.
Where to put it? Or hang?
Due to the fact that the storage water heater must store in its womb the entire volume of water heated by it, it can have a very impressive size. What limits its use in typical urban apartments: Well, for example, how to build a 100-liter tank in a narrow, as a pencil case, bathroom!
And how much hot water do you really need?. Statistics, which have long ago calculated us from all sides, know the answer to this question as well. Based on many years of practice has been compiled a table of necessary volumes of the storage device, depending on where it is used and the number of people in the family.
You can wash up or wash your own dishes?
It turns out that in the kitchen or washbasin, where hot water is often needed a little at a time, a small storage tank that can be placed under or above the sink is enough. It is more difficult, but still possible, to carve out a place for a storage unit for a shower.
And quite complicated – for a 100 liter appliance that provides hot water for a bath… True, engineers are trying to at least partially help this problem by giving the storage units a flatter shape or placing them horizontally.
To estimate how long the stored volume of hot water will last, you must take into account that the amount of usable water is about twice the volume of the storage tank. The explanation is simple: since the water in the accumulator is heated to 65-85 ° C, it is mixed with the same amount of cold water.
In practice this means that heating water in a 15-liter water storage tank, you can wash dishes or wash your face for 7-15 minutes at a normal flow rate of 2-4 liters per minute . , and the 30-liter variant gives the possibility to stand under the shower for 8-12 minutes the flow rate is 5-8 l/min . .
Not too comfortable, but taking into account the rising tariffs for water and electricity, we still have to get used to some restrictions.
Hot water in the apartment – without the housing maintenance company?
Water heaters that supply hot water to only one faucet are used together with a special faucet that closes the water at the inlet to the device when the faucet is closed. Thus, they are not under pressure from the water supply network, and therefore are called non-pressurized or open .
In contrast, pressure otherwise closed water heaters are built into the hot water system and work under the pressure of the water system. Therefore, the tanks of such devices are made of steel, capable of withstanding the pressure up to 10 bar in the water supply system it is usually in the range of 2-6 bar , and they should operate only together with a group of safety.
This group consists of a pressure reducer that reduces the pressure at the inlet of the device to 3-4 bar, a check valve to prevent drainage from the tank at water shutoff this saves the heater from overheating and the excess pressure valve, through which the “excess” liquid is drained.
The additional complications associated with building into the system are more than offset by the ability to use a single device to serve multiple taps.
And if your apartment has the conditions for installation of a large-capacity flow heater 3-phase network or a large volume storage tank, you can use one device to provide all points from which the hot water is taken – taps in the kitchen and bathroom, shower.
Thus completely replace the centralized supply – with all its advantages, but without the indispensable and so annoying disadvantages.
When a safety group is required?
Pressure closed version – the water heater is constantly under pressure, embedded in a hot water supply system can serve several outlets. Requires a safety group.
Unpressurized open version – the water from the water supply network is shut off before entering the device. When heating the water inside the tank does not create excessive pressure, because the “excess” water easily dribbles through the spout of a specially designed faucet.
Top and bottom connections for small water heaters. Products with upper supply are designed for installation above the sink, so that the connections look downwards and the control panel is at the bottom of the front panel. Devices with a bottom supply are designed for installation under the sink: the spigots look up, the control panel is at the top of the front surface.
Protection class – the degree of electrical safety of appliances in accordance with international IP degree of protection. Class “IP 24” or “IP 25” means that the device is protected from moisture, splashing or jets of water, so it can be installed in the bathroom.
How can I ensure that my water heater continues to provide hot water throughout the summer season without any issues or disruptions?
Is it necessary to have a water heater during the summer months when the water supply is already warm? What are the potential benefits and drawbacks of using a water heater in the summer?