Since we are talking about calculations, it means that initial data figures will be required. Each person uses water differently. For some, it’s enough to stay in the shower for 5 minutes, while others swim in the bath twice every day.
If you decide to purchase a boiler and choose a type and model, first of all study your needs. At least measure your bathing and dishwashing time. Let's calculate how much hot water is needed, what volume of boiler is needed for this and its power. How much and what he will take from the boiler and what the boiler will need for this.
Indirect heating boiler
Which indirect heating boiler is better to buy?
When choosing any type of boiler, including indirect, it is important to consider the volume of the storage tank. There should be at least 30 liters per person, but 50 liters is better.
In this case, the container must be commensurate with the volume of the heat exchanger so that the water warms up faster.
The internal coating of the tank can be made of steel and stainless steel, which are characterized by durability. Enamel or glass-ceramic coating will provide better protection against moisture.
The functionality of boilers is affected by the presence of various options, for example:
- Recirculation function - provides a quick supply of hot water by constantly maintaining the temperature of the liquid in the pipes.
- Additional electric heating element – provides additional heating or maintenance of water temperature, and is also used for heating in emergency situations of the boiler or in the summer.
- The presence of a safety valve and anode (magnesium, titanium) - extends the life of the boiler
- Temperature sensor and thermostat - allow you to set the degree of water heating.
Important characteristics of indirect boilers are the maximum water heating temperature, dimensions and type of installation (wall-mounted, floor-mounted, horizontal, vertical), as well as the type of pipe connection (side, bottom, top), and the type of water connection connector in inches. The choice depends on the specific operating conditions.
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Connection diagram
To correctly connect a heating unit with your own hands, you need to know the basic boiler wiring diagrams.
The connection consists of supplying coolant to the boiler (it must enter the heat exchanger through the upper pipe) and its output, as well as inserting the device into the water supply system. Cold water should enter through the pipe installed on the bottom of the tank, and hot water should be discharged through the top.
This connection diagram allows you to obtain the highest efficiency for a specific device model.
Typical connection diagrams:
- Using a three-way channel. The principle of operation of such a system is that the coolant of the house heating system can pass through two lines (the main one, passing from the boiler to the radiators, and the additional one through the indirect boiler). Flow control is carried out using a three-way valve controlled by a thermostat. Initially, when the container is filled with cold water, the valve directs the coolant flow through the boiler heat exchanger; when the temperature in the tank reaches the set temperature, the thermostat switches the valve and the heating system works directly to the radiators. The switching process is repeated cyclically as the water temperature decreases. This scheme provides an economical mode of heat extraction from the coolant and allows you to maintain the water temperature in the boiler at a given level.
- With two pumps.
Several main lines depart from the tank, each equipped with its own pump, which allows you to maintain the required pressure for each line (for heated floors it is high, and for hot water supply points it is low).
- With hydraulic boom. When connecting the device to complex lines (many circuits with different pressures, household points, heated floors, etc.). Special balancing valves allow you to avoid pressure drops in the system, maintaining it constant in all sections of the main line. Installing and setting up such a system is beyond the power of a home craftsman, since the work will require a special tool and specific skills, so when implementing such a scheme, it is recommended to turn to specialists.
- With recycling. In some models of heating units, the introduction of a recirculation line is allowed. Constantly flowing hot water is pumped through the boiler tank. Although such a system requires the operation of a recirculation pump, it allows you to use hot water immediately after opening the tap, without draining cold water.
The best indirect heating boilers up to 100 l
For 1-2 people and a small number of water intake points, boilers with a tank volume of up to 100 liters are optimal. They will provide the family with the necessary amount of warm water without wasting extra energy and time on heating the excess liquid.
Protherm WH B60Z
5
★★★★★
editorial assessment
100%
buyers recommend this product
The WH B60Z model from Protherm is not only an efficient, but also a stylish boiler designed for domestic use.
It has a unique coil design with two tubes of different diameters, which ensures high equipment efficiency.
The boiler heats water up to 85 degrees maximum and is able to maintain the set temperature at the same level. There is a recirculation option.
The installation of the water heater can be either wall-mounted or floor-mounted with a right or left water connection. The model is equipped with a high-quality titanium anode and has an antibacterial coating on the tank, designed for 53 liters.
Advantages:
- Stylish design;
- High efficiency;
- Unique twin heat exchanger;
- High heating temperature;
- Universal installation;
- Antibacterial coating.
Flaws:
- Expensive.
Reliable polyurethane thermal insulation, heating speed, protective systems and minimal energy consumption - all this makes the WH B60Z boiler from Protherm one of the leaders in the modern water heater market.
TML BMX 100
5
★★★★★
editorial assessment
100%
buyers recommend this product
The TML indirect boiler is designed for the production and storage of hot water for sanitary purposes. It is suitable for both horizontal and vertical installation and holds 100 liters of liquid.
The tank and heat exchanger of the equipment are made of stainless steel, processed by passaging and etching, resistant to mechanical damage.
And the thermal insulation layer is made of hard polyurethane 25 mm thick, which ensures excellent temperature retention.
The standard equipment of the boiler includes a magnesium anode. As an option, you can use a non-consumable electronic element, as well as an electric heating element, thermostat, thermometer and recirculation line. The boiler is capable of heating water up to +95° C.
Advantages:
- Universal installation;
- Possibility of additional equipment;
- High heating temperature;
- High-quality thermal insulation;
- Stainless steel tank.
Flaws:
- High price.
The indirect heating boiler BMX 100 from TML is universal in use, suitable for installation in large and small rooms and can work with gas and solid fuel boilers.
Drazice OKC 100 NTR/Z
4.9
★★★★★
editorial assessment
93%
buyers recommend this product
The compact water heater NTR from Drazice is designed for floor installation, modification Z is for wall installation.
The boiler is used for indirect heating of non-edible water to +90° C. It is equipped with a working thermostat and has a thermometer that displays the actual water temperature.
The boiler is equipped with a 95 liter tank with an internal coating made of corrosion-resistant enamel. Overheat protection and a safety valve extend the operating life of the equipment.
And the service hatch makes it easy to monitor the internal cleanliness of the tank. Additional installation of heating elements is possible.
Advantages:
- Options for wall and floor installation;
- Thermostat;
- Possibility of installing a heating element;
- Service hatch;
- Very high heating temperature.
Flaws:
- Not suitable for heating drinking water.
Indirect heating boiler OKC 100 from Drazice is reliable and durable equipment for a small family or small office.
Hajdu AQ IND 75 FC
4.8
★★★★★
editorial assessment
89%
buyers recommend this product
The compact boiler from Hajdu is designed for fast and economical heating of water. It has a vertical wall installation with a bottom water supply, allowing it to be placed in a small space above other equipment or plumbing.
The device is equipped with a copper heater, which ensures rapid heating of water to a maximum of 65 degrees. If desired, an electric heating element can be installed on the boiler.
The 75 liter tank is covered with glass-ceramic enamel. Together with the magnesium anode, this provides excellent corrosion protection.
The water heated by the boiler is suitable not only for sanitary needs, but also for food. The water heater is equipped with a thermostat and thermostat.
Advantages:
- Compact dimensions;
- Fast water heating;
- Excellent corrosion protection;
- Suitability for food purposes;
- Thermostat and thermostat;
- Recycle.
Flaws:
- Not the highest heating temperature.
The AQ IND 75 FC water heater from Hajdu is optimal for a family of 1-3 people. At the same time, it is quite economical because it does not overheat the water.
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Heat accumulator for heating boilers: design features and connections
The purpose of using this unit is to collect and store coolant heated to a certain temperature for its further transfer to the system when the need arises. Being connected to the water circuit of the room, a battery of this type ensures temperature maintenance even if the heat source is turned off.
The heat accumulator is used to maintain water heated to a certain temperature
This device also performs other functions. The main ones include:
- Reduces fuel consumption by almost a third. At the same time, the efficiency of the fuel installation increases;
- protects heating devices from overheating by collecting excess heat;
- heats water for the domestic hot water system. That is, in fact, this is one of the types of indirect heating boiler. The price of this unit varies within a very wide range: from 13 to more than 300 thousand rubles;
- the heat storage tank can connect several heat sources operating on different types of energy or fuel;
- The design of the device allows for the selection of coolant at different temperatures.
Design of a heat accumulator and rational connection of external devices
The main part of this unit is a cylindrical stainless tank filled with a liquid characterized by a high heat transfer coefficient. Its piping is carried out with heat-insulating material. In combination with the installation of a top jacket, this design solution increases the cooling time of the heat accumulator. Inside the cylindrical container there are 1 to 3 heat exchangers. The number of coils is determined by the capabilities and needs of the homeowners.
Heated water from solid fuel or gas boilers enters the cavity of the battery tank from above, and the cooled liquid settles closer to the bottom and is pumped back into the boiler for heating.
Diagram of a heat accumulator with the ability to connect to alternative energy sources
The lower compartment usually has a temperature of about 35-40°C. Therefore, it is advisable to connect it to a heated floor system. The temperature of the middle part is 60-65°C. Therefore, heating devices should be connected to it. The top of the tank is connected to the hot water supply. The water temperature there reaches 80-85°C.
The best indirect heating boilers for 100-200 l
For a large family, medium-sized office or enterprise, water heaters with a medium tank are used. Such boilers are designed to provide water for up to 6 people or more if we are talking about non-domestic reduced consumption.
Nibe Quattro OW-E 200.7
5
★★★★★
editorial assessment
100%
buyers recommend this product
A modern and highly efficient boiler, despite the tank holding 200 liters of water, is suitable for wall mounting. The main difference between the water heater is the presence of a ceramic heating element as standard.
It does not come into contact with water, therefore it does not corrode, and is capable of reheating the liquid or working independently when the boiler is turned off.
The boiler has protection against overheating and is equipped with a valve against high pressure in the system. It is able to connect to boilers of different types of energy used. The water heater has a recirculation line and is able to maintain the water temperature at the same level.
Advantages:
- Electric heating element;
- Wall installation;
- Overheat protection;
- Safety valve;
- Temperature maintenance mode.
Flaws:
- Price.
The boiler OW-E 200.7 from Nibe Quattro is suitable for use at home and in small industries.
Reflex US 150
4.9
★★★★★
editorial assessment
93%
buyers recommend this product
US 150 water heaters from Reflex are available in 4 body designs: blue, red, gray and white. They can be used with boilers of the same brand as a stand, as they provide for horizontal floor mounting.
The boiler tank holds up to 150 liters of liquid, and it has an enamel coating that preserves the hygienic purity of water suitable for drinking.
The enlarged heat exchanger ensures rapid heating of water to a maximum temperature of +95 degrees. At the same time, it can withstand pressure up to 16 bar, and capacity up to 10 bar. Protection against corrosion is provided by a magnesium anode.
Advantages:
- Different body colors;
- Magnesium anode included;
- High heating temperature;
- Withstands high pressure;
- Suitable for drinking water.
Flaws:
- Used for floor horizontal installation only.
US 150 boilers from Reflex are practical and safe, so they can be used for domestic purposes.
Kospel SWR 120
4.9
★★★★★
editorial assessment
90%
buyers recommend this product
The Kospel SWR series boiler has a tank with a capacity of 120 liters. This is a budget line of water heaters, which is distinguished by high energy efficiency. The device is equipped with a heat exchanger reaching the bottom of the tank with a power of 12.9 kW.
It ensures uniform and fast heating of water. The current temperature is displayed on a thermometer located on the body; the maximum value is +80 °C.
The boiler has a sleeve that allows you to connect to it an automatic heating boiler system, as well as pipes for recirculation equipment that maintains the water temperature in the pipes.
Effective thermal insulation of the water heater eliminates large heat losses, and the magnesium anode protects the surface of the enamel tank from rust.
Advantages:
- Low price;
- Quiet operation;
- High efficiency;
- Efficient operation of the coil;
- Sleeve for boiler automation;
- Built-in thermometer.
Flaws:
- The warranty is 1 year, while analogues have a minimum of 5 years.
The inexpensive but effective boiler SWR 120 from Kospel is optimal for a family of 3 people.
Hajdu STA200C
4.8
★★★★★
editorial assessment
87%
buyers recommend this product
The indirect heating boiler STA200C from Hajdu is an easy-to-use unit that can heat up to 200 liters of water to a temperature of 65 degrees.
The body is made of plastic, which provides additional thermal insulation and is not subject to corrosion.
The internal heat-insulating layer is made of environmentally friendly material that does not emit toxic substances when heated.
The boiler has a vertical floor installation. A heat exchanger with an increased volume guarantees fast heating of water, and the glass ceramic coating of the tank protects it from rust.
The water heater can withstand water pressure up to 10 bar, which makes it suitable for use in systems with several water intake points at once.
Advantages:
- Large tank with glass ceramic coating;
- Fast water heating;
- Excellent thermal insulation;
- Recycling;
- Withstands high pressure.
Flaws:
- The protective anode is not included;
- Low heating temperature.
The STA200C volumetric boiler from Hajdu is suitable for use with gas, solid fuel and liquid fuel boilers.
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Criterias of choice
To make the right choice, you need to take into account the characteristics and features of the device.
- Power . The documents indicate the total and net power. So, at 24 kW, only 15 kW will be spent on heating, since the rest is spent on the water heater. Think about how much power will be enough to meet your family's needs.
- Capacity . Based on the number of consumers. The volume of 100 liters is enough for showering and household needs of three people. If you are installing in a country house, 80 liters will be enough.
The duration of heating depends on the volume of the tank. Therefore, if you choose a roomy model, make sure that there is also enough power.
- Heat source . Would it be more convenient for you to use solid fuel or gas? It may be better to purchase equipment with a heating element, then it will be able to work all year round.
- Coil area and material . The larger the heat exchanger, the faster the water will heat up. For example, with an area of 1 m², 120 liters will heat up in 30 minutes. Copper and brass give off heat best.
- Tank quality . What material is it made of? It is best to choose from stainless steel or steel. This design will last much longer. Pay attention to the internal coating - ceramics and glass ceramics protect the product well from corrosion.
- Dimensions and method of placement . The body can be rectangular or round. Products from 150 liters are floor-mounted, since the wall may not withstand heavy loads. Wall-mounted models can be installed vertically and horizontally.
- Availability of heat exchangers . Conventional devices are equipped with one coil. But if the boiler is connected to an additional energy source, it is better to choose two coolants.
- Quality of thermal insulation . The most common layer is foam rubber. The latest models use polyurethane.
- Magnesium anode . It must be included in the design to provide protection against corrosion and scale.
- Protection . Special sensors and a safety valve provide the device with a long service life.
Pay attention to the warranty period. Make sure service centers are available in your city.
We looked at the design and operating principle of an indirect boiler. Let's start looking for interesting models.
The best indirect heating boilers for 200-400 l
Boilers with a tank of more than 200 liters are used in multi-storey country cottages, offices and enterprises to provide sanitary water.
ACV Smart Line SLE 300
5
★★★★★
editorial assessment
100%
buyers recommend this product
The boiler has a spacious stainless steel tank with a capacity of 293 liters. The body is made of polypropylene, which is scratch-resistant and gives it an original appearance.
And polyurethane foam thermal insulation ensures long-term preservation of the temperature of heated water.
The water heater is equipped with an electric heating element, thermostat, thermometer and recirculation system. It has overheating protection and self-cleaning technology against scale.
Advantages:
- Heats up in 20 minutes;
- Electric heating element;
- Thermostat;
- Self-cleaning from scale;
- Scratch-resistant housing.
Flaws:
- Expensive.
The SLE 300 boiler from ACV is a modern, highly efficient equipment that is suitable for year-round provision of hot water.
Thermex ER 300V (combi)
4.9
★★★★★
editorial assessment
95%
buyers recommend this product
The ER 300V boiler from Thermex has a classic round shape. It is designed to produce and maintain hot water temperatures up to 75 °C.
The water heater is equipped with a 300 liter tank with a unique bioglass porcelain coating, which ensures a long service life.
The standard package includes an electric heating element, which increases efficiency and ensures autonomy of the water heater.
The efficiency and ease of use of the boiler is increased by the presence of a thermostat, thermometer and recirculation. And protection is guaranteed by a safety valve and an overheating protection system.
Advantages:
- Heavy-duty tank coating;
- Electric heating element;
- Thermostat and thermometer;
- Safety valve;
- Recycle.
Flaws:
- Heavy weight.
The performance of the ER 300V boiler from Thermex is sufficient for technical water supply to a family of 6 or more people, as well as for medium-sized production.
Drazice OKC 300 NTRR/BP
4.9
★★★★★
editorial assessment
90%
buyers recommend this product
The OKC 300 series NTRR/BP boiler from Drazice is a reliable piece of equipment with high efficiency. It is designed for heating non-edible water.
The boiler tank is designed for 295 liters of liquid. Two spiral heat exchangers provide rapid heating of water up to 90 degrees. And the magnesium anode protects the surface of the enamel-coated container from corrosion.
The water heater has a working thermostat, a thermometer and a water heating alarm. There is also a service hatch for easy maintenance. Additionally, you can connect an electric heating element to it.
Advantages:
- Two heat exchangers;
- High heating temperature;
- Thermostat and thermometer;
- Service hatch.
Flaws:
- Not suitable for drinking water.
Boiler OKC 300 NTRR/BP from Drazice is an ideal solution for organizing hot water supply in places where there is no centralized supply of hot water.
The best indirect heating boilers for industrial use (from 500 l)
Boilers with a tank of 500 liters or more are used for industrial purposes or for hot water supply to large offices, hotels, institutions, and farms. They have increased dimensions and a high price, but are characterized by reliability and operational efficiency.
Sunsystem SON 1000
5
★★★★★
editorial assessment
98%
buyers recommend this product
The productive and dimensional water heater SON 1000 from Sunsystem is equipped with a 1000 liter tank. For uniform and efficient heating of water, the design includes 2 heat exchangers with a total thermal power of 105 kW.
They allow you to connect two heating sources to the boiler at once, for example, a gas or solid fuel boiler and a solar battery.
The water heater has highly effective thermal insulation and a convenient viewing window. Titanium enamel and anode protect the tank from corrosion. Additionally, you can connect a heating element.
Advantages:
- Titanium enamel;
- Two heat exchangers;
- High thermal insulation;
- Two energy sources.
Flaws:
- Large dimensions.
The SON 1000 boiler from Sunsystem is designed for use in large industries and requires sufficient installation space.
Ferroli Ecounit F 500 2C
4.9
★★★★★
editorial assessment
92%
buyers recommend this product
The Ferroli boiler has an ergonomic and practical body and high operating efficiency. It is equipped with a 500 liter tank with increased thickness of the enamel coating and a large magnesium anode, which provides reliable protection against rust.
Thanks to two heat exchangers, the water in the boiler heats up quickly and evenly. Visual temperature control can be carried out using the built-in thermometer (maximum +93 degrees).
The presence of thermal insulation with a thickness of 50 mm guarantees high-quality preservation of the temperature of the heated liquid.
Advantages:
- Two heat exchangers;
- Increased enamel layer;
- Large anode;
- High heating temperature;
- Thermometer.
Flaws:
- Electric heating element must be purchased separately.
The optimal number of boiler users for domestic purposes or in a hotel or sanatorium is 10-12 people.
