Accumulation water heaters: Hot water – always!

The reasons why people think about buying a system for cooking hot water, there may be several. Urban residents purchase is associated with periodic summer water outages, cottagers – with a general increase in the level of comfort of living in nature, but for permanent residents of the country is not so much a question of comfort as of basic comfort: Heat all winter basins on the stove or stove – an occupation long and thankless. Variety of systems are many. Hot water can be obtained from home heating boilers, water pumps, solar collectors they also work in winter, though not as efficiently as in summer or from independent heaters, gas or electric.

Stiebel Eltron SNU small storage water heater

Heating water with electricity is a very costly method, nevertheless one of the most popular. All other methods require in many cases a supply of fuel lines and always require expensive equipment. And every home has an electrical network, and the devices themselves are relatively cheap and require relatively uncomplicated installation.

There are two types of electric heaters: flowing and storage combined circuit, where electricity is used only as a “supplement” to other heating system, we will not consider at this time .

The flow heater is convenient for instant water, simplicity and compact size. These models are usually used for a single point of water extraction, often with infrequent use in the country or in the city during hot water outages in the summertime. In theory, you can get an unlimited amount of water, but in practice its volume is limited by the maximum power that is realistically available from the mains.

Roughly you can estimate that 1 kW electric power heater is 0.5-1 liter of warm water per minute depends on the temperature inlet and outlet , and further calculation depends on wiring. Can a regular household network withstand even 5-6 kW – a big question, in rural areas the wiring is not always designed for such power. Three-phase network allows more power, but not everyone has it.

The accumulation heater in this respect is more convenient. Domestic models consume less power than an electric kettle, and give out enough water to meet the needs of several people. Cold water is supplied to the tank either from the central water supply or from any other water sources. The only important thing is to have a constant pressure in the supply line, and whether it is created by a pump, a pumping station or by gravity from a tank located several meters above is immaterial.

A few hours after turning on the heater in the network at the owner’s disposal are several tens or hundreds of liters of hot water. Even if

leave the tap open for a long time, the water temperature will drop slowly: the incoming water will dilute the water in the boiler, in addition, the turned on heater will “add” a few degrees more. Since water consumption is an irregular process, it will not bring any special inconvenience, the water in the tank will have warmed up by the next opening of the faucet. This is quite convenient, and it is about storage water heaters for domestic purposes and will be discussed further.

HEATERS OUTSIDE AND INSIDE

From the user’s point of view, most heaters are “black boxes” usually white . Two connectors for connecting pipes, an electrical cable, a relatively small control panel, well, maybe even a separate thermometer – that’s all that is visible from the outside. And from the manufacturer’s point of view, appearance is just what the sales of the model on the market depend on. The shape of the casing can be rectangular, cylindrical or “flattened cylinder” – to reduce the depth.

Material is usually powder-coated steel, less often plastic or for beauty – stainless steel. At the ends of the body closes with covers. Generally found in the wall-mounted design, “floor-standing” models are found only among the especially capacious heaters.

In the wall-mounted version there are two varieties: vertical and horizontal. A considerable number of firms produce heaters separately for horizontal and vertical installation. The difference between them is the location of water nozzles: at the end or at the side. True, some models can operate in both positions, but this must be clarified when choosing.

The main part of any storage water heater – tank. It is most often made of steel and coated with enamel. The tank is subjected to high thermal loads, and the durability of the entire device depends on its reliability repair in case of a leaky tank is not reasonable . Enamel protects against corrosion and must be strong and elastic, so as not to crack during operation as long as possible. Different manufacturers use a slightly different composition of enamel and apply different methods.

Less often stainless steel is used as a tank material, sometimes with a special protective coating. Welding is carried out in an argon environment. Theoretically stainless steel is more durable, but not always. The main place of possible leaks – welds, in which the composition of steel differs from the basic alloy this feature is typical for stainless steel: welded it is worse than conventional iron, and its fusible components “burn out” . Even less often tanks are made of copper or plastic.

To answer the question “what is better, enamel or stainless steel” is not unambiguous. The enamel coating is chemically inert, but only until the enamel gets microcracked and starts to crumble. On the other hand, stainless steel for the tank should be “food grade”, i.e. e. very good quality, and to achieve a hermetic sealing of seams technologically is not so easy. Crumbled enamel is easy to see during maintenance of the heater about it below , it is a clear sign that the hot water is no longer “sanitary”, but the tank can still serve for quite a long time.

Control the condition of the stainless steel tank by inspection is unlikely to be able to up to the start of the leak. By the way, because of the impossibility to guarantee constant quality of water, it is not recommended to use hot water as drinking water even in conditions of centralized water supply in the city.

Of course, inexpensive models, the main savings come at the expense of simplifying the tank material, coating and welding quality. How long will the heater no name – is unknown, and the quality of water in it is likely to be worse than the well-known brands, which are more careful to perform the tank.

leading manufacturers warranty on the tank is 5-10 years more than the electronic components of the device .

BETWEEN THE CASE AND THE TANK

The rest of the heater elements do not have a significant impact on water quality and either do not require maintenance, or can be easily replaced if broken. Let’s start with what is “between the case and the tank” – with insulation. In its role it is usually accepted to use different types of foams of high density, which “fill” all free internal space, such as polyurethane foam.

It is much denser and heavier than the usual packing foam or construction foam, although, in fact, does not differ from them. A layer of thickness of a few centimeters is enough for almost total insulation: the cooling of water in the tank occurs at a rate of a fraction of a degree per hour. Making the layer even thicker is not always advisable: the size grows much faster than the loss of heat, and for household heaters the size of the case is of no small importance.

The heaters, or electric tube heaters, can be of different shapes and constructions, from simple curved tubes or spirals to the same elements, placed in a protective enameled casing to reduce limescale. Actually, it is the fight against limescale that explains their diversity. The power of the heater – a constant value, systems of smoothly changing the power of water heaters are rare: to be able to work in different modes set a few heaters usually two .

In a normal mode one works, if its power is not enough for the rapid heating – the second is connected if you install two heating elements of different power, you can get and three-mode regulation, when they turn on or off separately, or both at once .

A magnesium anode, which is a pin made of magnesium alloy, is almost always used to protect the internal surfaces and heaters from scaling. The principle is simple: dissolved oxygen and salts react more readily with magnesium than with the metal in the tank harmless, easily soluble compounds are formed in the reaction, but not as a hard limescale. The anode is a consumable item and should be replaced from time to time.

How often – depends on the quantity and quality of the water in the tank. If the anode is “burned out”, the corrosive activity increases sharply, and the tank quickly fails. Another type of protective anodes, not consumable, but requiring a separate power supply active anode , is found quite rarely on domestic models.

Anode, heating elements and the thermostat sensor are mounted on the flange that is installed on the bottom of the heater. The flange is either bolted through the gasket or, less frequently, screwed into the tank. Water inlet and outlet are provided by means of two pipes which also pass through the flange. A short supply pipe ends at the bottom of the tank, next to the heating elements. Heated water is lighter than cold water so it is drawn from the top of the tank. This tube works as an overflow, at the same time protecting the tank from emptying heating elements are not designed to work in a “dry” mode .

OTHER ELEMENTS OF WATER HEATERS

Safety Group. It includes several elements. So, so that the hot water does not drain from the tank, “exposing” the heaters, it is taken from the top of. But theoretically possible and leakage of water back into the supply pipe. A non-return valve serves to prevent it. A faucet or forced draining device must be installed between the heater and the supply pipe and a valve to relieve excess pressure. Safety group is usually a part of the set and can be installed separately from the heater.

Thermostat. Compulsory element of any heater. Used to control the water temperature. Gives the command to turn on/off when the set temperatures are reached their difference is only a few degrees . In case of malfunction or breakdown of the thermostat the heater is equipped with a sensor that shuts down heating when the maximum allowable temperature usually 90 ° C Many models have a built-in safety switch-off device in case of problems in the electrical circuit.

Thermostat. This element can not be called mandatory, but some models have a special thermometer mounted on the body. It has more aesthetic value, but when choosing a heater in the store, the thermometer can distinguish the model from many others.

Control panel. For the same purpose of recognition, the design of the panels in many manufacturers is a subject of particular care. In the simple case on the panel are rotary temperature regulator, indicators of power and heating modes. Some devices may not even have a start button. Recently models with LED or LCD displays, push-button or touch screen control, a choice of many different modes and the ability to program them are becoming more and more popular. Particularly “advanced” models have devices for external control.

Above are all the basic and additional elements of any heater. Finally, let’s return to its tank, or rather, to the peculiarities of design of some models. Outwardly they look the same, but they have two tanks inside, heating elements installed one per tank, in the first – the supply pipe, in the second – the suction pipe. Why is it done so? The fact that at a large flow rate can be a situation where the hot water will have a noticeable uneven temperature: the layers simply do not have time to mix.

But here the tanks are connected by several tubes-overflows, probably with breakers. In the long run in the first tank will be cold water, which through overflows and dissipators “dilute” the hotter water in the second. Of course, the temperature in this tank at high flow will decrease at the same rate as in the usual, single, but the temperature at the outlet will decrease more evenly.

Accumulation electric water heater Ariston ABS Velis Power

CONNECTION AND SERVICE

To build a water heater into the heating system, no special technical knowledge is required, but skills will come in handy. First you need to determine the input and output of water and bring the pipes to the installation area, then attach the heater to the wall. Why in this order? All depends on the material of the pipes to be connected and the place of installation. If you use a steel pipe, it is logical to do so, steel is very inconvenient to fit to the threaded connections on the water heater, it is easier to “move” it a little.

For flexible liner or pipes from softer materials such restrictions do not exist, but at least pre-assemble most of the plumbing is better in advance. Service life of a flexible rubber hose very often because of the simplicity of installation put it in most manufacturers – no more than five years, then it needs to change.

I do not want to repeat trivial things, but it is worth remembering that at the outlet of the heater will be hot water and need an appropriate hose “for hot water”. On the inlet pipe must be a valve that blocks the water, as well as a check valve and a drain valve, if they are not included with the heater.

Pre-treatment and softening of water – an element not necessary, but desirable. Here everything depends on its quality: it is one thing if the water is pumped through the “rusty” central water pipeline and another thing if you have your own water supply system. And here at least a simple filter that detains mechanical impurities will be useful in any case.

Fixing the wall heater – the problem is not too difficult. Of course, we should take into account that its total weight after filling is not so small, so that both the wall and the hooks for mounting should be sufficiently reliable.

The last connection that you need to make is to the network. Most household class heaters have a regular electrical plug, all you need is a socket with obligatory grounding. A separate circuit breaker is not superfluous.

After installation, the heater must be filled with water by opening the inlet faucet and hot water faucet on the faucet.

Maintenance of heaters is easy. Many do not do it, and in vain. Manufacturers recommend usually once a year to clean the heating element and replace the magnesium anode, if installed and worn. To do this, disconnect the unit from the network, shut off the water, open the faucet, then drain the water using the drain faucet and remove the flange. Anode wear is determined by eye, at the same time through a hole in the tank you can assess its condition although, for example, if the enamel is crumbling, the tank is still not repairable . At assembling it is sometimes necessary to change sealing gasket.

HOW TO SAVE?

Any technique is available in at least a few categories: from simple models to “premium”, and it depends not so much on the brand, as on the positioning of the model by the manufacturer. The choice of a particular brand depends on personal preferences of the buyer and the options offered. We will not consider this question: someone buys brands, and someone prefers to argue that “for such money you can buy two”.

\Often this is the case, but sometimes in the lifetime of one heater from a well-known manufacturer you can have time to throw away more products, whose only merit – “inexpensive”. By the way, many models, even from well-known brands, are made in China although there are still many “native” . Now it does not matter: it is not where they produce, but how they control, and the Chinese model made under the name and control of a serious company, in terms of quality can be no worse than the “white” assembly. But buying a cheap no name is a lottery with a not so great probability of winning.

The main way to save when buying a heater is to choose a model with the necessary and sufficient tank volume. At the same time will save not only a certain amount in the purse, but also space in the room. How to calculate the required volume? It is necessary to know the number of family members, to present the characteristics of water consumption during the day and total consumption per day. For one person for washing dishes and hands may be enough and ten liters of heater, the shower will be enough for about 30 liters, and if you have a bath – and then 50-80 liters may not be enough this is for hot water, cold we do not count . For several people the volume should be increased, in the first approximation – for each subsequent family member needs a heater with a tank volume of 20-30 liters more.

Of course, if the device is bought in an urban apartment to cover the planned summer outages, its volume can be less: there is not much space in the apartment, a few weeks can survive and a small tank to have enough “in stock.

If the heater is the only source of hot water, a little reserve on the volume does not hurt. To estimate how long it will take the heater to heat a new portion, you need to know the temperature of the incoming water it is about 5 ° C, and in summer in the city could be higher, up to 15 ° C and the desired temperature. This calculation is not difficult, the documentation necessarily includes time for heating water to a certain number of degrees, and to estimate after how much time the temperature will be considered comfortable, it is not difficult.

Saving during operation is quite simple – you need to spend less. Paying for electricity from your wallet quickly teaches you to be careful with hot water. Energy-saving technology, such as “smart” faucets, can also cut down on consumption.

Some models have a “night” mode on. If you have a two-tariff meter you can save money by heating water during the period of low tariff. By the way, it does not always make sense to keep hot water of high temperature in the tank. Programmable models are more reasonable to set up for cooking hot water at the right time usually in the morning , and the rest of the time to keep in the tank “strategic reserve” of water with a relatively low temperature of course, this can be done manually, turning the thermostat in advance .

In terms of increasing the life of the boiler, the lower the water temperature in the tank, the better: not only saving energy, but also its elements are less exposed to thermal stress, and corrosive activity with a decrease in temperature decreases. But from time to time the temperature should be raised. The fact is that in the tank creates good conditions for the reproduction of certain types of bacteria, including dangerous. They die at temperatures above 65 ° C.

And another way to save money – timely maintenance of the tank and replacement of the anode. Frequency of maintenance is specified by the manufacturer: most often it is recommended to check the condition of the anode, the heaters and the tank – once a year. With proper maintenance these devices can serve for many years, which means that the need for a new one will not arise for a long time.

AEG Haustechnik DEM 100 Basis storage water heater