Indirect heating boiler: device, principle of operation and connection diagrams. What is an indirect heating boiler and how does it work
The need for an expansion tank for domestic hot water is constantly being challenged. Moreover, for many experienced plumbers, the inclusion of a node in the hot water supply system causes at least bewilderment. On the other hand, many manufacturers of plumbing equipment recommend installing a tank for indirect heating boilers. The purpose of the node is quite simple: to reduce the load in the system and eliminate water hammer.
Even an approximate calculation of the expansion tank for an indirect heating boiler will show that its minimum volume will be at least 10% of the water contained in the BKN. And this is an additional capacity of 10-20 liters, occupying a usable area. Not surprisingly, one of the most common questions asked by specialists is related to how much an expansion tank is needed for hot water. To answer it, you need to understand the device and the principle of operation of the equipment.
Why do you need an expansion tank for BKN
talking plain language this is necessary to protect hot water equipment from water hammer. Such a need arises if the need for hot water is satisfied by an indirect heating boiler connected to a solid fuel boiler.Control the intensity of combustion and heat transfer of the boiler for solid fuel despite not all the equipment used is quite problematic. When heated, the water expands and creates excess pressure in the system, which leads to water hammer.
The membrane tank levels pressure drops and protects water taps, pipes and the boiler itself from damage. It happens like this: 
Inside the indirect heating boiler there is a heating element connected to the heating system. When the coolant overheats, the DHW temperature rises, the load on pipes and important structural elements increases, which leads to damage to expensive plumbing equipment.
The principle of operation of the expansion tank with the BKN safety group is to prevent high pressure in the DHW system and the occurrence of water hammer. There are non-return and relief valves to help in emergency situations.
Connecting the safety group and expansion tank necessary condition for long-term operation of the BKN, as well as free maintenance. Equipment manufacturers often refuse warranty repairs if safety equipment is not installed in the boiler piping.
How to calculate the volume of the expansion tank for BKN
The simplest calculations that will give an approximate result are as follows. The volume of the tank must be at least 10% of the total volume of the BKN. Consequently:- a boiler of 100 liters is connected to a tank of at least 10 liters;
- 200 liter water heater, needs a 20 liter tank.
- Selection of an expansion tank for BKN for its intended purpose. The water in the hot water supply is more aggressive than in the heating system. The technical documentation for the buffer tank should indicate the main purpose. You can only put a tank on the boiler, the instructions of which indicate the possibility of using it for hot water supply.
- Calculation by pressure - the choice of an expansion tank for BKN is facilitated by special selection tables. Input parameters: what initial air pressure should be in the expansion tank for the DHW boiler:
Maximum pressure Рmax, bar
Initial gas pressure Р₀, bar
- The choice of the membrane - the rubber used in the tank affects the quality of the liquid supplied to the hot water supply and the service life of the safety tank. Common materials for the manufacture of membranes:
Natural rubber rubber for potable and non-potable water. Operating temperature range from -10 to +50°С. Elastic, but allows partial diffusion of water. Scope - accumulation cold water.
Synthetic butyl rubber for potable and non-potable water. Operating temperature range from -10 to +100°С. Less elastic than NATURAL, but durable in terms of water resistance. Scope - water supply stations (the most versatile material).
Synthetic ethylene/propylene rubber for potable and non-potable water. Operating temperature range from -10 to +100°С. More moisture permeable than butyl.
It is used only for non-potable water (heating boilers). Operating temperature range from -10 to +100°С. Less elastic.
Used for active media (oils, fuels). Operating temperature range from -10 to +100°С.
- Selection based on the coefficient of thermal expansion of system fluids:
To facilitate calculations, you can use special online calculators. In the initial parameters, you will need to enter the volume of the boiler. After that, the program will calculate the volume and initial pressure in the gas cavity.
The hydraulic tank for hot water supply has a blue body (white), for heating it is red.
Connection diagram for a boiler with an expansion tank
The binding is performed as follows:- Water is supplied to the BKN through a check valve. Such a measure will prevent the flow of heated coolant into the cold water system.
- It is better to place the expansion tank in the DHW system between the non-return valve and the boiler. This is necessary so that when the tap is opened, the user immediately receives hot water.
It is allowed to connect the expansion tank to the BKN when the RB is placed after the boiler. There will be no functional differences in the operation of the security group. At the same time, cooled water from the Republic of Belarus will first enter the hot water supply, which is not entirely comfortable.
If the piping of the boiler with the expansion tank is done correctly when heating the DHW, the safety valve will not work. It is important to avoid two extremes:
- Expansion tank transfer- in this case, the pressure will squeeze out all the water from the tank. Consequences: water hammer and damage to plumbing equipment when water overheats. You need to reduce the pressure in the tank. To calculate the initial parameters, you can use the table above.
- Underestimated indicators of RB- when the coolant is heated, the safety valves will be torn off. Accordingly, the effectiveness of the security group will be reduced to zero. If you do not raise the pressure in the tank, even with a slight overheating of the coolant, the safety group will work.
Article plan
If you live in a private house, then installing an indirect heating boiler together with a boiler will kill two birds with one stone - heat the house and provide constant access to hot water. We have selected for you best models water heaters that can be found on sale today - choose!
Briefly about the main characteristics
In conventional storage water heaters, the liquid temperature rises due to the operation of heating elements, while in boilers, heating is carried out due to the circulation of a heated coolant in the system. It looks something like this: water is heated in a single- or double-circuit boiler and fed through pipes to a coil or other heat exchanger installed in the tank; at the same time, cold water enters the tank from the main, which is subsequently heated due to heat exchange through the walls of the coil. Instead of a coil, a tank-in-tank design can be provided. In this case, the coolant is supplied to the external tank, and the heated liquid is supplied to the internal one. The presence of temperature and liquid volume sensors inside the tank, as well as automatic relays, ensure the smooth operation of the equipment. Some models are also equipped with additional electric heaters - even in case of force majeure, you can use the boiler hot water. Everything seems to be simple, but before buying it is necessary to understand the main technical characteristics of such equipment.
| Selection criterion | Varieties | Note |
|---|---|---|
| Volume of the tank | from 50 to 400 liters and more | In the most popular models for domestic use, tanks with a volume of 80 to 200 liters are used. The volume is selected based on the flow hot water and the number of water points. |
| Power | from 2 to 60 kW and above | Together with the volume of the tank, the power determines the rate of heating of the liquid. The more powerful the equipment and the smaller the capacity, the faster the heating goes. |
| Max water pressure | 6-10 bar (0.6-1 MPa) | The pressure that the boiler can withstand in operating mode. It is advisable to install pressure reducers to prevent damage from water hammer. |
| Mounting method | Wall | Equipment with a small tank volume (up to 100 liters) is often attached to the wall. The larger the volume, the more difficult it is to do this, so capacious water heaters are made in the floor version. |
| Floor | ||
| Combined | ||
| Heat exchanger design | Coil | The heat carrier from the boiler is supplied through a metal coil installed in a tank with heated water. The most common type. |
| coil in coil | The heat exchange area is increased due to the use of two coils with different spiral diameters. | |
| Tank in a tank | There are two steel tanks - one inside the other. The coolant from the boiler is supplied to the larger tank, heated water is supplied to the smaller one. | |
| Heat exchanger material | Stainless steel, brass | The vast majority are made of stainless steel. However, this material may vary in quality. Therefore, you should not save and buy products of an unknown brand. |
| Material and thickness of the thermal insulation layer | Foam rubber, mineral wool, expanded polystyrene, polyurethane foam - from 20 to 60 mm thick | The effectiveness of thermal insulation is determined by the value of thermal conductivity (the less, the better) and the thickness of the insulation layer (the more, the better). To date, a good solution is the use of 50-60 mm polyurethane foam insulation. |
| Maximum productivity in flow mode when heated to ΔT °C, l/min | where ΔT °C = 25, 45, 55 etc. | Determines the efficiency of the heater in flow mode. Depends on its power. |
| Heating time per ΔT °C, min. | where ΔT °C = 25, 45, 55, 60 etc. | Determines the heating rate of the entire volume of water in the tank. Depends on size and power. |
| Options | heating element | Many models can be upgraded with tubular electric heaters that fire when the boiler is turned off. |
| recycling | The tank may be provided with a circuit for water circulation using a pump. This is necessary so that water is supplied to the consumer at a constant temperature. | |
| Solar collectors | The use of solar energy to heat the coolant with the subsequent transfer of heat to water heating. Collectors are installed on the roof. In the CIS, this option is relevant only in the warm season. | |
| Heat pump | Ability to connect a heat pump to minimize the cost of heating cold water. A very rare option. |
We omitted such a parameter as the thread diameter for connecting to pipes, because. this issue, if necessary, is solved by installing adapters.
Calculation of the volume of water
Only you can determine exactly the required volume, because. calculations are tied to the conditions of water consumption. Our task is to provide information that will somehow help in the choice or suggest thoughts when making the calculation. For example, we open SNiP 2.04.01-85 and see that the norms set 7.9-10.9 liters of hot water (HW) per hour per person. Following some simple calculations, we get the following table.
These calculations can only be taken into account if the water heated by the boiler is consistently used and one draw-off point is operating at the same time (only one tap is open). In practice, the given values \u200b\u200bmust be multiplied by 3-5. Why it happens? Because the norms do not take into account the desire to bask in the shower (+20 l. HW) and take a bath (+80 l. HW), wash a mountain of dishes (+20 l. HW), etc. etc. Take into account the peak loads on the boiler - choose the volume that is most suitable for your needs.
- 50-60 liters is enough for 1 person;
- for 2-3 people you need to choose from models of 80-120 liters;
- for a family of 3-5 people, the capacity of a boiler of 120-200 liters is enough
To make it easier for you to choose suitable model equipment, we have identified four product groups depending on the volume of the storage tank: up to 100, 200, 300 and 400 liters. Everything specifications taken from open sources and prices are for comparison purposes only.
Important! Please note that some water heaters are only suitable for certain models of boilers. In the description, we will focus on this, but we recommend that you clarify all the nuances before buying.
Up to 100 liters
1. Baxi Combi 80 (80 liters) - from 52,500 rubles.
A notorious Italian player specializing in heating and water heating equipment, Baxi has been holding the quality mark for decades. The Baxi Combi 80 small volume boiler model is designed to work in conjunction with the LUNA-3 Comfort series boilers of the same manufacturer. Placement is floor, the water heater can be installed directly under the boiler, saving space. One of the advantages of this system is its compact dimensions. Corrosion protection is provided by the use of stainless steel and a magnesium anode. Polyurethane foam is used as thermal insulation. TENA connection is not provided.
2. Gorenje GBK80ORRNB6 (72.6 liters) - from 24,000 rubles.
When looking for a small model that can provide hot water for one or two people, pay attention to Slovenian equipment. This is a classic compact boiler with two tubular heat exchangers, the performance of which is enough for two points of water intake at once. The device is equipped with an electronic control unit and allows you to change the DHW temperature in the range of 15-75 °C. It has outlets for connecting to the boiler on the right side, two dry heating elements are installed as an additional heater. The model is equipped with several types of protection: against corrosion (magnesium anode), against freezing (effective thermal insulation), against overheating and heating without water. The manufacturer also provides a function to control legionellosis (a lung disease whose pathogens actively multiply in hot water). One of the best combined solutions in terms of price / quality ratio.
* operating parameters in flow mode are not specified by the manufacturer. The power of the heat exchanger itself is not indicated - only for the heating element.
3. Protherm FS B100S (95 liters) - from 36200 rubles.
The Czech boiler is structurally tied to the boilers of the same manufacturer - the Bear. Compact, with a concise but informative control panel, it easily fits into the kitchen interior as built-in appliances. Enamelled stainless steel, magnesium anode and antibacterial coating - all aimed at protection against corrosion and microorganisms. The tubular heat exchanger provides a high rate of heating of the entire volume of liquid: water is heated by 50 degrees in 13 minutes. To keep warm, the product is protected by a polyurethane foam coat.
4. ACV COMFORT 100 (100 liters) - from 48,000 rubles.
The Belgian manufacturer with almost a century of history offers interesting solution based on a tank-in-tank heat exchanger - model . The boiler consists of two stainless steel containers of different volumes, one of which is inserted into the other. Particular attention should be paid to the internal container: its surface is corrugated, therefore, due to thermal expansion, a change in size takes place, followed by the removal of the formed plaque of hardness salts (scale). The equipment is installed on the floor by default, but with the help of additional fixings it is possible to mount it on the wall. The heat-insulating layer is made of polyurethane foam 30 mm thick. The set of standard functions is small, but an optional control panel can be installed. It is also worth considering the lack of the possibility of recycling and connecting the heating element.
Up to 200 liters
5. Baxi Premier plus 150 (150 liters) - from 50,600 rubles.
It is possible to ensure the full operation of two hot water points with the help of. In a series of these heaters, a tubular coil-in-coil heat exchanger is used. Due to its low weight, the device can be hung on a wall or placed on the floor. The parts of the structure that come into contact with water are made of DUPLEX stainless steel, the minimization of heat losses is achieved by the use of polyurethane foam. The model is equipped with a thermostat and can be used in conjunction with any type of boilers. Optionally, it is possible to connect a tubular electric heater. The manufacturer has provided for the connection of the recirculation circuit. According to reviews, this is one of the best solutions in terms of price and quality for a family of four.
6. BOSCH WSTB 160 (160 liters) - from 28,000 rubles.
If a gas boiler is installed in your house, then you should think about buying a water heater. Although there is no possibility of connecting a heating element here, there is a recirculation system. The model is adapted to the harsh conditions of use in the CIS, i.e. suitable for hard water. To protect steel from corrosion, the material is coated with a special composition of glass-ceramic. There is a recirculation line so you can always count on getting water at a constant temperature. To minimize heat losses, a fur coat of 50 mm polyurethane foam is provided, the lining is made of PVC, soft. Front connection, it is possible to connect temperature sensor. The entire volume is heated to ΔT=45°C in 37 minutes.
7. Protherm FE 200 BM (184 liters) - from 41650 rubles.
Many manufacturers offer storage heaters that are only suitable for their boiler models. If you have installed a Proterm boiler, then in order to satisfy requests big family in the hot water supply, it is worth considering the installation. This is an indirect floor standing boiler made of stainless steel, enameled for corrosion protection. The installed titanium anode serves the same purpose. To prevent bacteria from multiplying on the walls of the container, they are covered with a layer of antibacterial substance. Productivity is high - with a delta of 25 degrees, you can get more than 30 liters of water per minute. Without the possibility of connecting the recirculation line and heating element.
8. Gorenje GV 200 (188.9 liters) - from 25,800 rubles.
Floor water heater of indirect type Combustion GV 200 - simplicity of the device, reliability of a design and laconic design. The product is an enameled steel tank with a tubular heat exchanger inside. Installed on the floor under the boiler. An overpressure relief valve is used as protection against overheating. The device is protected from corrosion by enamel and magnesium anode. It takes up to 24 minutes to heat the entire volume of water in the tank from 15 to 75 degrees. A 40 mm thick thermal insulation layer is responsible for maintaining the temperature of the hot water supply.
* the possibility of working in flow mode is not announced by the manufacturer
Up to 300 liters
9. ACV COMFORT 240 (240 l.) - from 65,000 rubles.
Another representative of indirect water heaters that use a tank-in-tank heat exchanger. The model is able to provide hot water to three points of water intake. The product is protected from corrosion due to the use of stainless steel and a special approach to the formation of the walls of the inner tank. Here it is corrugated, which has a positive effect on its work even with very hard water. At the same time, the equipment is characterized by the same features as for products of the same series: a minimum of functions, a thermal insulation layer of 30 mm, the inability to connect a tubular electric heater and a recirculation circuit.
10. Protherm FS B300S (295 liters) - from 63,000 rubles.
This accumulator is intended for use with Proterm Grizzly or Bizon boilers. - a capacious tank with a tubular heat exchanger. There are two flanges in the tank: for installing a heating element and servicing the boiler. Enamelled surfaces that come into contact with water, as well as the presence of a titanium anode, protect equipment from corrosion. Not to mention the presence of an antibacterial coating. A layer of polyurethane insulation is responsible for reducing heat loss. The device is characterized by high performance in flow mode, it is possible to connect a recirculation line. The possibilities of this heater will be appreciated by the owners of large private houses with more than three bathrooms.
11. Baxi Premier plus 300 (300 liters) - from 70,000 rubles.
Often the main criterion for choosing a boiler is not only its volume, but also the heating rate. In this case, it is relevant to consider models with a coil-in-coil heat exchanger. - exactly what is needed! Firstly, it is compatible with any boilers. Secondly, high-quality stainless steel, perfectly protected from corrosion, is used for its production. Thirdly, with a fairly compact size and low weight, the equipment has a universal placement and is equipped with an accurate thermostat. The model allows you to supplement the system with a recirculation circuit. Connecting a heating element for 2.7 kW is optional.
Up to 400 liters
12. Drazice OKC 400 NTRR / 1 MPa (380 liters) - from 68,000 rubles.
The Czech boiler is equipped with two tubular heat exchangers, one of which is designed to be connected to a solar collector, and the second to the boiler. This allows you to save a lot on heating water in sunny days, especially in the summer. If necessary, for example, a malfunction of the boiler equipment, two auxiliary electric heating elements can be mounted. The enameled tank, as well as the presence of a magnesium anode, provide long-term protection of the tank from corrosion. 50 mm rigid polyurethane foam is used as a heat-insulating layer. There is a recirculation pipe.
Information on the rate of water heating in flow mode is not provided by the manufacturer. This is due to the presence of two independent heat exchangers with different temperature conditions.
13. Bosch SK 400-3 ZB (388 l.) - from 59,500 rubles.
There are not so many indirect water heaters of the capacity we are interested in in the Bosch assortment, but among them there is a special model - Bosch SK 400-3 ZB. This is an enameled tank with a stainless steel coil. Corrosion protection is represented by a magnesium anode, which has already become a natural phenomenon in such equipment. The device is quite simple: a built-in thermometer and a flange for easy maintenance. At the same time, it is possible to connect a hot water recirculation line, as well as to synchronize with the boiler if the latter has an NTC sensor connector (thermal sensor). Those. you can fine-tune the operation of water heating equipment. Separately, it must be said about thermal insulation. Here it is not polyurethane foam, but made of rigid foam, which, with an equal thickness, gives a lower heat-shielding effect.
14. BAXI UBVT 400 SC (395 l.) - from 58100 rubles.
If the prevailing part of the boilers is designed to work in tandem with the boiler, then the model is an exception to the rule. It is adapted for connection to a solar collector, so its purchase will be appropriate in two cases: in places with year-round sunny weather or for seasonal use. Additionally, for heating, it is possible to install electric heaters. The container itself is made of steel coated with titanium enamel - it turned out to be a corrosion-resistant and durable coating. The latter is also facilitated by the presence of a magnesium anode. The kit includes a thermometer for temperature control, there are sockets for connecting sensors. The design provides a flange for monitoring the condition of the coil, as well as a built-in pipe for recirculation.
15. Hajdu STA 400 C (400 liters) - from 64,100 rubles.
The model from the notorious Hungarian manufacturer is interesting in that with one heat exchanger, fine-tuning of the equipment is possible. So, in the cold season, such an indirect heating boiler can be configured to work in tandem with the boiler, while in the summer it can be connected to a solar collector. In the latter case, if necessary, the heating element is additionally connected. The tank and heat exchanger are protected from corrosion by a layer of hot enamel and a magnesium anode. To minimize heat loss, the container is covered on the outside with a layer of polyurethane foam protected by a plastic casing. A branch pipe is provided for connecting a DHW recirculation system.
In the next video, this boiler is presented in section.
Editor's Choice
For ease of comparison, we will enter the main characteristics in the table and decide on the most successful models. To make it clearer, we choose a boiler for 1-2 people, 2-4 people, 4-6 people. (marked in the table below in bold from top to bottom, respectively). Because far from all manufacturers adhere to uniform standards when preparing technical documentation, for example, not all indicate the value of performance in the flow mode, then we introduce the characteristic N. It shows the ratio of a unit of power per 1 liter. water. Those. we simply took and divided the capacities indicated by the manufacturer by the useful volume of drives. The larger this value, the faster the heating takes place.
| Model name | Useful volume, l | power, kWt | N, kW/l | Accommodation | heat exchanger | heating element | rec-tion | price, rub. |
|---|---|---|---|---|---|---|---|---|
| 80 | 31 | 0,3875 | outdoor | coil | — | — | 52500 | |
| 72,6 | 2 | 0,027548 | wall | coil | + | — | 24000 | |
| 95 | 26,1 | 0,274737 | outdoor | coil | — | — | 36200 | |
| 100 | 23 | 0,23 | floor/wall | tank in a tank | — | — | 48000 | |
| 150 | 30 | 0,2 | floor/wall | serpentine in serpentine | + | + | 50600 | |
| 160 | 20,8 | 0,13 | wall | coil | — | + | 28000 | |
| 184 | 43,2 | 0,234783 | outdoor | coil | — | — | 41650 | |
| 188,9 | 17,6 | 0,093171 | outdoor | coil | — | — | 25800 | |
| 240 | 53 | 0,220833 | floor/wall | tank in a tank | — | — | 65000 | |
| Gorenje KGV 300-2/BG | 280 | 69,6 | 0,248571 | outdoor | coil | + | + | 83700 |
| 295 | 46 | 0,155932 | outdoor | coil | + | + | 63000 | |
| 300 | 30 | 0,1 | floor/wall | serpentine in serpentine | + | + | 70000 | |
| 380 | 57 | 0,15 | outdoor | coil | + | + | 68000 | |
| 388 | 60 | 0,154639 | outdoor | coil | — | + | 59500 |
Indirect heating boilers Lapesa Geiser Inox "D"
Feature of the indirect heating boiler Geiser Inox "D" is a tank-in-tank system, it heats water through heat exchange between the external and internal tank (DHW tank) from external sources of heat energy, which can be a heating boiler, heat pump, etc. Also interesting and useful feature is an the possibility of cleaning the surface of the inner tank: they are equipped with a special upper flange for revision and cleaning, through which, having previously removed the lining on the cold and hot water pipes, access and cleaning of the internal DHW tank is carried out.
The company produces a wide range of water heaters of various capacities and volumes, ranging from large-capacity industrial tanks to conventional household tanks (which include Geizer Inox): models with a heating element built into the primary circuit, models that do not require Maintenance, special high performance boilers for renewable energy, models for low temperature systems, combined, for installation in municipal buildings, in private homes.
Stainless steel, due to its hygienic characteristics and resistance to corrosion, is an excellent material for the production of water heaters. It is from this steel that all models of Lapesa Geizer Inox indirection systems are made. The latest manufacturing techniques, special processing after the welding process and strict quality control have led to the creation of some of the most reliable boilers on the market, having long term operation and meeting strict modern hygienic requirements. Stainless steel is easy to clean, active rinsing can be used, disinfectants can be used (for example, anti-legionella treatment). Sacrificial anode deposits and deposits do not form in stainless steel water heaters, as cathodic protection is not required under normal operating conditions. In cases where you have to work with particularly aggressive water, the water heaters are supplied with permanent cathodic protection Correx-up, which does not require maintenance. Stainless steel is a non-toxic material, so Lapesa indirect heating tanks can be safely used in the food industry - tests show that stainless steel is comparable to glass and porcelain. The mechanical strength of stainless steel ensures the resistance of the tank to loads that may arise as a result of pressure surges, water hammer, etc.
Technologically, the design was conceived in such a way as to provide each boiler model with maximum efficiency when working with various systems heat exchange, thanks to the wavy surface of the inner tank.
Particular attention in the production of Lapes indirect heating boilers is paid to the quality of thermal insulation - they are made of polyurethane foam and allow you to save thermal energy without wasting your money, minimize heat loss and significantly increase the ability to store hot water for a long time.
Attention!
Since August 2015, the Lapes company has changed the marking of boilers model range GX, (technical specifications do not change):
Changed the same external design– black covers and control panels change to grey. 
Advantages of Lapesa indirect heating boilers
- The tank-in-tank system ensures maximum performance.
- The Lapesa boiler can be mounted both vertically and horizontally. There are options for floor or wall mounting, as well as many additional options.
- Are completed with heating elements and the control panel (models GX-D).
- Tank capacity from 100 to 600 liters. Maximum operating temperature 90/110 °C, maximum operating pressure 8 bar.
- Stainless steel AISI 316 - protects against chlorides twice as well as AISI 304L steel.
- Welding of the inner tank is carried out on automatic lines. Welds are protected from the inside (passivation, pickling), unlike boilers from other manufacturers. The weld becomes more resistant to corrosion after it is first leveled at Lapesa production, and then rid of the porous oxide layer formed on its surface, under which there is a zone with an insufficient percentage of chromium. For this, pickling (or chemical etching) is used.
- Maximum fast cooking hot water thanks to energy efficient system heat transfer
- Large heat exchange surface due to the undulating surface of the inner tank.
- Lapesa boilers are maintenance-free and provide a long service life.
- The flange with stainless steel inlet and outlet pipes is removable and allows you to easily inspect or clean the inside of the tank.
- The cantilever mounting and the wavy surface of the walls of the inner tank contribute to self-cleaning from scale in case of pressure and temperature drops.
- High quality insulation: CFC-free rigid polyurethane foam. Heat loss is only 0.25 °C per hour.
- Increased thermal insulation in the upper part of the boiler in the zone of greatest heat loss.
- Boilers Lapesa provide increased hygiene.
- Legionella protection.
- Ability to store water at temperatures over 60°C
- No unheated zones, guaranteed temperature distribution throughout the tank.
- All Lapesa water heaters of the GEISER INOX series can be equipped with the LAPESA Correx-up automatic cathodic protection system, which is recommended to be installed in regions with increased water aggressiveness (high chloride content, more than 150 mg/l). Externally powered Correx anode provides electronic cathodic protection storage water heater during the entire period of its operation and does not require service and replacement. The system is powered by 220V.
- Stamped neck of the inner tank, which during production allows access to the inside of the tank and protect all internal seams, and in operation - to inspect and maintain the inner surface of the tank.
The device and main characteristics of indirect heating boilers Lapesa Geiser Inox "D"
TANK IN TANK system is a heat exchanger consisting of two tanks inserted one into the other: the inner tank for domestic hot water is heated by the heat transfer medium of the heating system, which circulates between the double walls in the outer tank.
The inner tank (2) works with corrosive running water, at variable pressure and temperature, and is made of AISI 304 chromium-nickel stainless steel, welded in a protective argon atmosphere by automatic welding. Welds, unlike boilers from other manufacturers, are also protected from the inside by chemical pickling (picking and passivation).
The stainless steel of the DHW tank reduces the cost of protecting boilers from corrosion, and also allows you to store hot water at a high (up to 90 ° C) temperature, which, when cold water is added, allows you to more than double the volume of hot water at a comfortable temperature.
Storage of hot water in the boiler at temperatures above 60°C is guaranteed protects against the development of pathogenic Legionella bacteria in the tank.
Large hole for flange mounting hot water intake and cold water supply pipes (1) allows you to passivate welds, which increases the life of the tank. Removable flange with stainless steel water inlet and outlet pipes allows you to easily examine the volume of the internal tank.
Also, this hole allows you to remove scale particles that have fallen off the undulating walls of the heat exchanger and accumulated at the bottom.
Wavy Profile(2) The wall of the inner tank provides a large heat transfer surface to speed up the water heating time.
Self-cleaning surface of the heat exchanger scale boiler. Thanks to the cantilever fastening of the inner tank in its upper part, it allows it to change its shape (stretch and shrink) with a constant change in pressure and temperature.
thermal insulation(6) CFC-free, high-density polyurethane foam, 5 cm thick.
Decorative cover (4) made of rigid white polypropylene.
Features of boilers Lapes GEISER INOX:
DHW tank in stainless steel AISI 304 L or AISI 316 L
DHW tank capacity: 60, 100, 150, 200, 300 and 500 liters
Maximum operating pressure in the DHW tank 8 bar (option 10 bar)
Maximum operating temperature in the DHW tank 90ºC
Maximum operating pressure in the heating circuit (primary circuit) 3 bar
Maximum operating temperature in the heating circuit (primary circuit) 110 ºC
Thermal insulation: rigid polyurethane foam (CFC-free, 0.025 W/mºK)
Vertical OR horizontal installation. Models up to and including 150 liters prepared for WALL MOUNTING (except TS models)
They have a side hole, as an option, a heating element for the primary circuit can be installed in it.
Equipment: Control panel type "K", mounted, wired, with thermometer, safety and control thermostat, winter-summer switch and indicator lights.
Technical characteristics of water heaters Lapesa GX
Accessories for indirect heating boilers Lapesa Geizer Inox "D"
Heating elements for indirect heating boilers Lapesa GX
| TENA model for vertical mounting | Heating element model For horizontal mounting | Power, kWt | Voltage, V | Recommended Boiler Models |
| RC 15/15 D | RC 15/15 I | 1,5 | 220 | GX-100D |
| RC 16/22D | RC 16/22 I | 2,2 | 220 | GX-130D |
| RC 17/22D | RC 17/22 I | 2,2 | 220 | GX-200D |
| RC 18/25 D | RC 18/25 I | 2,5 | 220 | GX-300D/400D |
| RC 08/45D | - | 4,5 | 220 | GX-600D |
| RC 50D | - | 5 | 380 | GX-600D |
| RC 75D | - | 7,5 | 380 | GX-600D |
Cathodic protection Correx
It consists of a titanium anode, suitably mounted on the top cover or, if necessary, on the side surface of the boiler, depending on the storage tank model. This anode is connected to a voltage regulator that automatically regulates the power supply.
An externally powered Correx anode provides electronic cathodic protection of the storage water heater during the entire period of its operation and does not require maintenance and replacement.
Power supply: from the mains 230 V.
Features of operation of boilers of indirect heating Lapesa
The pipeline for supplying cold water to the boiler must be equipped with a safety group consisting of at least:
- stopcock
– check valve
- safety valve
– expansion tank for domestic hot water system
To compensate for thermal expansion in the sanitary water circuit, it is necessary to install an expansion tank with a capacity of:
5 liters for GX 100/150 models
8 liters for GX 200
18 liters for GX 300
24 liters for GX 600
