The cascade method of connecting boilers has been used for many years. The concept is simple: divide the total heating load between two or more independently controlled boilers, and turn on only those boilers that satisfy the demand for a given load at a given time. Each boiler represents its own “stage” of heating output in the total power of the system. An intelligent controller (microcontroller) constantly monitors the temperature of the coolant supply and determines which stages of the system should be turned on to maintain the set temperature.

ADVANTAGES
using a cascade system:

Increased seasonal efficiency of the system compared to using one powerful boiler;
-partial load coverage even if one of the boilers is switched off, for example, for maintenance work. This is especially important in harsh climates, where low temperatures can cause an inoperative system to freeze very quickly;
-a cascade system is much easier to install than one large boiler, especially when upgrading the system. In addition, spare parts for less powerful boilers are cheaper;
- the ability to simultaneously provide both high loads for hot water supply or anti-icing, and much lower loads for heating.

We present the performance characteristics of two different cascade systems in relation to a hypothetical load diagram. The first system uses two boilers with single-stage burners, each capable of supplying 50% of the design load. The second system uses four boilers with single-stage burners, each of which can supply 25% of the design load. It is obvious that a system of four boilers instead of two is able to more effectively provide the conditions of the design loads. Based on this, it can be assumed that the more stages in the cascade system, the better it satisfies the loads. This is especially effective when the required power is low. However, as the number of stages increases, the heat transfer surface area of ​​the system (boiler casing) through which heat loss occurs increases, which can ultimately negate the benefits increased efficiency such a system. Therefore, it is not always advisable to use more than four stages. An inherent limitation of a “simple” cascade system (boilers with single-stage or two-stage burners) - step-by-step regulation of heating output (system power), rather than a continuous controlled process. Although the use of more than two stages significantly reduces the heating output of each boiler, the ideal solution would be a “modulated” cascade system (boilers with modulating burners). Modulating burners allow you to continuously adjust the power depending on the heat demand, without changing the quantitative fuel/air ratio, i.e. when, depending on the volume of supplied air and aerodynamic drag the amount of fuel supplied to the combustion chamber changes. This ensures stable boiler efficiency and minimal concentrations of pollutants in the flue gases under variable heat load. Next step. The latest trend in solving cascade systems is the modulated cascade system. Unlike the use of staged burners, boilers with modulating burners are able to smoothly change the volume of fuel supply, and therefore control the level of heating output over a wide range of values. Today, the heating equipment market is widely represented by low-power boilers with modulating burners, capable of smoothly changing the boiler performance in the range of 30–100% of the rated thermal power. The ability of boilers with modulating burners to reduce fuel consumption is often called the burner operating control coefficient (i.e., the ratio of the boiler’s maximum thermal output to its minimum). For example, the operating regulation coefficient of a boiler burner with a maximum thermal power of 50 kW and minimum consumption 10 kW of fuel will be equal to 50 kW/10 kW or 5:1. The total operating regulation coefficient of boilers installed in a cascade system significantly exceeds the coefficient of an individual boiler. For example, if a cascade system uses four boilers with a maximum heating output of 50 kW and a minimum of 10 kW, the total output control will be in the range from 200 kW to 10 kW. Consequently, the operating regulation ratio of such a system will be 20:1. In conditions of low heat output, the heat exchanger of a boiler with a modulating burner operates at a relatively low temperature of the heat exchange surfaces of the boiler on the combustion side. When such a boiler is used to satisfy low loads, e.g. underfloor heating, its operation is usually accompanied by continuous condensation of flue gases. To avoid damage to the heat exchanger due to condensation in modern boilers with modulating burners use heat exchangers made of of stainless steel or aluminum. When operating at low temperatures, the efficiency of such boilers can exceed 95%. Low-power boilers with modulating burners are usually designed with closed camera combustion, which expands the set design solutions for air supply and combustion product removal systems, since the chimneys of such boilers do not necessarily have to be straight. Typically, chimneys are made of galvanized sheet or stainless steel or aluminum. But for some boiler models, for example the Vaillant VU 505, a system of flexible polypropylene chimneys is successfully used (they can be installed in old, indirect or unsuitable smoke channels for normal operation).

System Features
There are three important features, which should be taken into account when designing a “modulated” cascade system. First. Features of the supply lines and controllers should allow independent adjustment of the flow circulation through each boiler. Water should not circulate through an idle boiler, otherwise the heat from the coolant will be dissipated through the heat exchanger or boiler casing. This also applies to the simple cascade system. Independent regulation of the coolant flow is achieved by equipping each boiler with an individual circulation pump. When installing circulation pumps in parallel, to prevent reverse flow coolant through idle boilers, check valves should be installed downstream of the pumps. Optimal solution this situation - installing a circulation pump with a wet rotor with built-in shut-off valves. The supply of coolant to each boiler using individual circulation pumps makes it possible to increase the pressure in the heat exchanger of an operating boiler in order to prevent cavitation and explosive steam formation.

Second important point- parallel connection of supply and return lines for each boiler (especially when using condensing boilers). This allows you to maintain the same water temperature at the inlet to each boiler and, if necessary, eliminate the flow of coolant between the circuits. The low temperature of the coolant supplied to the boiler promotes the condensation of water vapor from combustion products and increases the efficiency of the system. Some cascade controllers for boilers with modulating burners are equipped with a “time delay” function, that is, they are able to turn on the circulation pump of a particular boiler shortly before turning on the burner. They can also keep the pumps running for some time after the burner is turned off. The first ensures that the boiler heat exchanger is heated by the warm supplied coolant of the system, which prevents thermal shock due to a significant temperature difference (and condensation of flue gases for conventional boilers) when the burner is ignited. The second is to utilize the residual heat of the heat exchanger, and not remove it through the ventilation system after the boiler has finished operating. And thirdly, it is very important that circulation pumps ensure adequate coolant flow through operating boilers, regardless of the system flow rate. Closely spaced T-junctions (Figure 2) or low pressure drop manifolds (Figure 3) provide flow diversion from the system flow to ensure adequate boiler flow regardless of flow changes in the distribution system. Closely spaced T-tube joints on the primary/secondary circuit are used to “shave off” the pressure differential of the circuits.

Modulated control
A multi-stage controller for a simple cascade system using PID (proportional-integral-derivative control) constantly measures the temperature of the coolant supplied to the system, compares it with the calculated value and determines which burner should be turned on and which should be turned off. To control the boiler cascade and achieve economical fuel consumption, it is necessary to use special automation. One of the cascade boilers acts as a “master” and is turned on first, the rest - “slaves” - are connected as needed. Automatic control allows you to transfer the role of the “master” from one boiler to another, as well as to carry out the turn-on sequence of the “slave” boilers and the temperature differentials for turning on each subsequent stage. If a malfunction occurs in the lead boiler, automatic change priority. If a request for heat does not come from any of the zones, the regulator will turn off all boilers, and when a demand signal arrives, it will put them into operation. After the last boiler is turned off, the circulation pump turns off with a time delay. In most "modulated" cascade systems, the control method is different. As a rule, control is aimed at maximizing the operating time of boilers in low temperature range and at partial power. Although different manufacturers offer different systems control, the generally accepted approach is the following: turning on the boiler, then modulating its operation to a level of heating output that satisfies the required load. If additional heat is required, the heating output of the first boiler is significantly reduced, the second boiler is turned on, and then the heating output of both boilers is correspondingly modulated to meet the required load. This scheme ensures that both boilers operate at lower heat outputs, and therefore in a more gentle mode, in contrast to the operation of one boiler at full power. This increases the heat exchange surface area, and therefore increases the likelihood of condensation of water vapor from the combustion products, as well as the efficiency of the system. Suppose that the load continues to increase and two boilers operating at a relatively high level of heating output cannot meet its conditions, then the second boiler reduces fuel consumption, the third is turned on and parallel modulation of the heating output of the second and third stages occurs. In some systems, the first boiler is also capable of reducing fuel consumption when the remaining stages are activated, therefore all three power stages can be controlled in parallel.

Operating modes
Most cascade controllers are capable of at least two operating modes. In heating mode, a weather-dependent control principle is implemented, that is, the set temperature value of the coolant supplied to the system depends on the external temperature. The lower the external temperature, the higher the set value for the supply temperature. This system eliminates the need to use a mixer between the boiler and heating consumers. In DHW mode, software control of the system is carried out when the set value of the temperature of the supplied coolant does not depend on external temperatures. In other words, a certain, sufficiently high temperature value is set, which ensures high level heat transfer through the secondary heat exchanger. This mode is usually used to provide more high temperature coolant supplied through a heat exchanger to DHW consumers and anti-icing systems. Modulating the boiler power leads to a significant reduction in the differential between the required and actual coolant temperatures, which prevents frequent “clocking” (turning on/off) of the boiler. Some controllers are also responsible for the operation of the main circulation pump and are connected to the dispatch system engineering equipment building.

Small, quiet and powerful
The ratio of physical size to heating output of some modulating burner boilers is truly impressive. For example, some manufacturers provide eight-stage “modulated” cascade systems with a heating output range of 30–960 kW. Therefore, the operating regulation ratio of such a system will be 32:1. Such a system can be placed indoors small area. Additional benefit- low noise system. The modern generation of low-power boilers with modulating burners provides space savings, high efficiency, quiet operation and reliability. This perfect solution V low temperature systems, such boilers are ideal for underfloor heating, anti-icing systems, pool heating, hot water systems, as well as heat pump systems, incl. geothermal. They have already gained a position in the field of heating private houses. As part of a cascade system, boilers with modulating burners represent a new alternative to industrial heating systems.

Today, many consumers choose gas heat generators (boilers) as the main source of heat and water supply. There are several types of installation of gas equipment:

1 . One heat generator is installed in the heating system.

2 . Several heat generators are installed in the heating system.

Let's consider the option of installing several heat generators into the system to compensate for heat losses. There are several types of control systems with this design: parallel activation of each boiler, when each of the boilers operates separately from each other, but for one system (heating, hot water supply, ventilation, etc.); and second, cascade switching on of boilers, when the equipment is mounted and connected in one common system of thermomechanical and electrical connection.

In this case, the cascade is united by a single control system.

So what is a cascade? A cascade is one of the most effective ways to increase the maximum power or increase the minimum power of one device, but more on that later, but for now, as an example, let's look at the operation of an individual heating point.

As practice shows, the equipment operates at maximum heat load from three to five months a year with a rated heat load of 60 to 100%, while the remaining time the equipment operates at reduced power (from 40 to 60%). Let's take as a basis the inter-heating period from March to September and the area of ​​the heated room is 1000 m2 or the heating of water in the hot water supply system. According to average calculations, 1 m 3 of burned gas provides approximately 10 kW of boiler power. This means that if you have heating device If one boiler with a capacity of 100 kW is used, then its minimum load will be 50 kW, which equals an average gas consumption of 5 m 3 per hour. If you have a cascade of three boilers connected to your system with a power of 36 kW each, then, as practice shows, one of the heat generators with a minimum load of 10.6 kW will be turned on, which equals an average gas consumption of 1.6 m 3 per hour. As a result, when operating in the system of one gas heat generator with such a minimum load during the inter-heating period, its gas consumption will be almost three times higher compared to cascade operation of boilers, and this will increase financial costs.

Typical installation diagrams for gas burner equipment (cascade) are as follows.

The first is a simple cascade. This scheme includes gas equipment with single-stage or two-stage burners. When installing such a circuit, the equipment operates according to the following principle: first, the first stage of the burner is switched on with a rated power of 70% (of the total boiler power), and if this power is not enough to compensate for heat losses, then the second stage with a power of 100% is switched on.

The second one is modulated. This installation scheme is more economical. It combines equipment with modulated burners. It is possible to smoothly change the volume of fuel supply and the ability to regulate heating output in a fairly wide range. That is, the equipment is turned on with a minimum thermal load of 40% and, if necessary, smoothly increases it to a power of 100% in steps of 1%.

The main advantages of a cascade system with two or more gas boilers over conventional systems, in which only one gas boiler is used as heating equipment, are as follows.

Firstly, The operation of gas equipment must be controlled using a cascade control unit or other automation. A multi-stage controller for a simple cascade system, using proportional-integral-derivative (PID) control, constantly measures the temperature of the coolant supplied to the system, compares it with the calculated value and determines which burner should be turned on and which should be turned off.

One of the cascade boilers plays the role of “master” and is turned on first, the rest, “slave”, are connected as needed. Automatic control allows you to transfer the role of the “master” from one boiler to another, as well as to carry out the sequence of switching on the “slaves”. The automation also carries out the order in which the equipment is switched on, which guarantees the same number of operating hours of the gas burner device. As a rule, the automatic control system is supplied complete with a sensor outside temperature, which makes it possible to control the modulation of the gas burner device (power and flow temperature) depending on the ambient temperature. For example, at an outside air temperature of 0 °C, the coolant temperature in the supply line will be 50 °C. At an outside temperature of -10 °C, the coolant will be supplied to the supply line at a temperature of 60 °C, etc. The lower the ambient temperature, the higher the coolant temperature. Automation will turn on the required number of boilers depending on the required power.

Secondly, This means saving gas and, as a result, preserving financial resources that can be used to reconstruct your facility. The ability of boilers with modulating burners to reduce fuel consumption is often called the burner operating regulation coefficient (the ratio of the maximum thermal power of the boiler to the minimum). How can this be realized? It's very simple, the system will do it for you.

Let's give an example - when the equipment operates at a power above 70%, increased consumption gas You have two boilers with a power of 24 kW each. First, the first boiler is turned on with a rated load of 9.4 kW and gradually increases it to 100% power. If one boiler is not enough, then the second boiler is turned on, for example, at 40% power. In total, the total load of both boilers will be 32 kW. The second option is to turn on the first boiler, also with a rated load of 9.4 kW, and gradually increase it to 70% power. If this power is not enough, then the second boiler is switched on at a power of also 70%, and the total load will also be 32 kW. When operating gas equipment in the second option, gas savings will range from 15 to 30%.

Third, This is the ease of transportation and installation of equipment. Several wall-mounted boilers are much easier to install or assemble than one powerful boiler. The rather small dimensions and weight of wall-mounted boilers determine the advantage of installing them in a cascade when installing roof-top boiler rooms, in basements or semi-basements. In particular, when installing such boiler houses, no additional costs are required for special equipment for lifting or transporting a powerful large boiler.

Fourthly, this is a reserve. If for any reason one of the boilers fails, for example, due to a heat generator failure, then the entire system will continue to operate at reduced or medium power. If one boiler is working in the system, and it “goes into error,” then the entire heating system will stop working, and in the cascade, each boiler is autonomous, and in the event of an error emergency situation Only the faulty unit will shut down.

Fifthly, These are the conditions of accommodation. A cascade of wall-mounted heat generators can be installed and operated in attached, built-in, free-standing, roof-top boiler rooms, etc.

In practice, there are many examples when, when reconstructing a facility, expanding and adding additional heat consumers, it was necessary to modernize the boiler room itself (replace the existing gas equipment with more powerful ones), which led to large financial losses, and with the cascade control option, you can, if necessary, simply add existing system one or more boilers.

There are several options for placing gas equipment: mounting the equipment on the wall, on specialized racks (mounts) in a row, or placing gas-burning equipment “back to back.”

So, cascade boiler houses are used in almost all areas, but they are most in demand in autonomous heat supply systems for one or more objects. When installing cascade control, potential customers and consumers do not need to build a heating main from centralized system heating, which, of course, has significant heat losses, especially with the DHW function.

Most profitable solution cascade control is the installation of this equipment in private homes, restaurants, hotels, shops different areas etc. If the customer knows how to count his money and wants to be sure of the safety, efficiency, reliability and quality of his equipment, then he will choose a boiler room consisting of a cascade of boilers.

Let's start with the fact that modern house, located with middle lane, there should be 2 boilers. It’s not even necessary to have 2 boilers, but two independent sources of thermal energy – that’s for sure.

We have already written about what kind of boilers or energy sources these could be in the article “”. It describes in more detail which boiler and which backup is needed and can be selected.

Today we’ll look at how to connect 2 or more heat generators into a single heating system and how to connect them. Why am I writing about 2 or more units? thermal equipment? Because there can be more than 1 main boiler, for example two gas boilers. And there may also be more than 1 backup boiler, for example, on different types fuel.

Connecting two or more main heat generators

Let us first consider a scheme in which we have two or more heat generators, which are the main ones and, when heating the house, run on the same fuel.

These are usually connected in a cascade in order to heat rooms from 500 sq.m. total area. Quite rarely, solid fuel boilers are combined together for main heating.

We are talking specifically about the main heat generators and heating of residential premises. For cascade and modular boiler houses for heating large industrial premises may include “batteries” of coal or fuel oil boilers in quantities of up to one dozen.

So, as mentioned above, they are connected in a cascade, when a second identical boiler or slightly less powerful one complements the first heat generator.

Usually, during the off-season and mild frosts, the first boiler in the cascade operates. In cold weather or when it is necessary to quickly reheat the premises, a second boiler in the cascade is connected to it to help.

In a cascade, the main boilers are connected in series to be heated by the first heat generator. At the same time, of course, in this combination it is possible to isolate each boiler and a bypass, which allows water to bypass the isolated boiler.

In case of problems, any of the heat generators can be turned off and repaired, while the second boiler will regularly heat water in the heating system.

There is no special alternative to this system. As practice shows, it is better and more reliable to have 2 boilers with a capacity of 40 kW each than one boiler with a capacity of 80 kW. This allows you to repair each individual boiler without stopping the heating system.

It also allows each of the boilers to operate at its full power if necessary. While 1 high-power boiler would operate only at half power and at an increased clock rate.

Parallel connection of boilers - pros and cons

We reviewed the main boilers above. Now let's look at connecting backup boilers, which should be in the system of any modern home.

If backup boilers are connected in parallel, then this option has its pros and cons.

The advantages of parallel connection of backup boilers are as follows:

• Each boiler can be connected and disconnected from each other independently.
• Each heat generator can be replaced with any other equipment. You can experiment with boiler settings.

Disadvantages of parallel connection of backup boilers:

• We'll have to work more with boiler piping, more soldering polypropylene pipes, more welding of steel pipes.
• As a result, more materials, pipes and fittings, and shut-off valves will be wasted.
• Boilers will not be able to work together in a single system without using additional equipment- hydraulic guns.
• Even after using the hydraulic arrow, there remains the need for complex configuration and coordination of such a boiler system according to the temperature of the water supply to the system, and.

The indicated pros and cons of parallel connection can be applied both to the connection of the main and backup heat generators, and to the connection of two or more backup heat generators using any type of fuel.

Serial connection of boilers - pros and cons

When serial connection two or more boilers, they will operate in the same way as the main boilers connected in cascade. The first boiler will heat the water, the second boiler will reheat it.

In this case, you should first install the boiler on the cheapest type of fuel for you. This can be a wood, coal or waste oil boiler. And behind it, in a cascade, there can be any backup boiler - be it diesel or pellet.

The main advantages of parallel connection of boilers:

• In the case of operation first, the heat exchangers of the second boiler will play the role of a kind of hydraulic separator, softening the impact on the entire heating system.
• The second reserve boiler can be turned on to reheat the water in the heating system in the coldest weather.

Disadvantages when using the parallel method of connecting backup heat generators in the boiler room:

• Longer path of water through the system with more turns and narrowing in connections and fittings.

Naturally, you cannot directly let the supply from one boiler into the inlet of another. In this case, you will not be able to disconnect either the first or the second boiler, if necessary.

Although from the point of view of coordinated heating of boiler water, this method will be the most effective. This can be achieved by installing bypass loops for each boiler.

Parallel and series connection of boilers - reviews

And here are a couple of reviews from users about parallel and series connection of heat generators in a heating system:

Anton Krivozvantsev, Khabarovsk Territory: I have one, it is the main one and heats the entire heating system. I'm happy with Rusnit, it's a normal boiler, in 4 years of operation 1 heating element burned out, I changed it myself, that's all for 30 minutes with a smoke break.

The KChM-5 boiler is connected to it, into which I built. The locomotive turned out to be a great one, it heats perfectly and, most importantly, the automation of the process is almost the same as that of an automatic pellet boiler.

These 2 boilers work in pairs, one after the other. The water that Rusnit did not heat is heated by the KChM-5 and the Pelletron-15 pellet burner. The system turned out the way it needed to be.

There is another review, this time about the parallel connection of 2 boilers in the boiler room:

Evgeny Skomorokhov, Moscow: My main boiler is, it runs mainly on wood. My backup boiler is the most common DON, which is connected to the system in parallel with the first one. It rarely lights up, and anyway, I inherited it along with the house I bought.

But 1 or 2 times a year, in January, you have to flood the old DON, when the water in the system almost boils, but the house is still a little cold. This is all due to poor insulation; I haven’t fully finished insulating the walls yet, and it would be nice to insulate the attic floors better.

When the insulation is completed, I think I won’t heat the old DON boiler at all, but I’ll leave it as a backup.

If you have comments on this material, please write them in the comment form below.

More on this topic on our website:

1. 
   Words " gas boilers“single-circuit floor heating” are unfamiliar to an inexperienced person and sound outrageously incomprehensible. Meanwhile, intense suburban construction popularizes...
2. 
   Buderus boilers Logano G-125 running on liquid fuel, are available in three capacities - 25, 32 and 40 kilowatts. Their main...
3. 
   The principle of operation of any gas boiler is that as a result of combustion gas fuel, is formed thermal energy, which is transferred to the coolant...
4. 
   Water floor heating convectors heat a room of any size evenly and in a short period of time. From the point of view of interior aesthetics, such...

It's no secret that centralized provision of heat to existing and newly built facilities is becoming more and more problematic every year. In particular: the lack of the possibility of objective accounting, large heat losses during transportation, subjectivity in determining the cost, the monopolistic nature of the activities of heat suppliers, the impossibility of increasing existing capacity, and, consequently, the ban on connecting additional consumers - these are just some of the problems due to which specialists' views turn to the side autonomous heating and hot water supply.
In this regard, in last years In our country, block boiler houses, modular boiler houses or cascade boiler houses are becoming increasingly popular.
The Termona-Bel company promotes on the domestic market heating equipment The Czech company Thermona, which has been working for many years towards improving equipment for autonomous heating. 13 years ago, specialists from Thermona were one of the first in the world to come up with the idea of ​​creating cascade boiler houses with a capacity from 8 to 1440 kW based on wall-mounted gas boilers.

A cascade based on THERM boilers is a sequential connection of several boilers (up to 16 units) into a single heating system with program control. The peculiarity of the connection and design of Therm boilers allows you to smoothly regulate the total power of all boilers in the cascade from the minimum power of one of the boilers. For example, when installing a cascade of 16 THERM TRIO 90 boilers, the total power of the boiler room will be 1440 kW, and the minimum – 36 kW, i.e. 2.5% of its maximum. For comparison, a modern boiler with a power of 1500 kW provides a control range from 1050 kW to 1500 kW, which is from 70 to 100% of power.
In technology heating systems cascade boiler house based on THERM boilers is an innovative method for optimizing the operation of high-power heating systems. It is quite obvious that the heat loss of the facility, and, accordingly, the power of the boiler house is calculated based on the lowest temperatures in the given region, and the actual load on the boiler house is significantly lower than the established one.
Practice has confirmed that in heating season approximately 80% of the operating period, the boiler room capacity is used at no more than 50%, and during the operating season, the load is, on average, 25-45%. Consequently, with such an uneven and often low load, one high-power boiler ( traditional system) will unnecessarily consume energy resources and ineffectively compensate for heat costs. In contrast, the cascade system smoothly ensures that the boiler room operates at the required power (over a wide range) regardless of the time of year by connecting several small boilers one after the other in series. Using cascade control with program control, the problem of determining the optimal ratio of the power of the boiler room and the heating system is solved. Thus, in the off-season and in conditions warm winters a cascade boiler house can operate for a long time at low temperatures coolant, which reduces heat radiation costs and system standby periods. At the same time, the temperature conditions of the object improve, that is, the comfort of the user.
The use of THERM DUO, TRIO and KD boilers in a cascade allows you to achieve the optimal ratio occupied area To installed capacity boiler room while maintaining one of the main advantages of cascade connection - an incomparably wide range of smooth power modulation. In the organization of the boiler room, single-circuit wall-mounted boilers with a capacity of 20, 28, 45 and 90 kW are used. From 2 to 16 units can be assembled in a cascade, depending on the required power. All boilers are modern, technically advanced gas appliances, having an efficiency of up to 94%, with a service life of at least 15-20 years.
A significant advantage of a cascade boiler house based on THERM boilers over traditional boiler houses is its high reliability and extended service life. High reliability of the boiler house is achieved due to collaboration several boilers in one system, and the failure of one of the boilers does not stop the operation of the heating system as a whole. Software, which forms the basis for the operation of the cascade boiler house, is designed in such a way that the boiler startup sequence changes daily. Consequently, if today the boiler is started first, then the next day it becomes the last in line and will start only if the boiler room needs to operate at full capacity. Due to this, the operational life of each boiler increases, which leads to an increase in the service life of the boiler room as a whole. An undoubted advantage in a cascade boiler room is the ability to connect a boiler indirect heating to each boiler (except for the manager). Thus, in a boiler room of 16 boilers, you can connect 15 boilers from 200 to 1000 liters each and thereby satisfy any need for hot water supply. The boiler automation gives preference to the preparation of domestic hot water, and if there is no need for its preparation, the boiler proceeds to work in the heating system together with other boilers. When the operation of a cascade boiler house changes from winter to summer mode operation, the DHW preparation mode remains, the heating system pumps are started automatically once a day, driving the coolant through the system, and the anti-freeze function remains active. The advantages of cascade connection of boilers undoubtedly include the ability to choose many options for the boiler room: location and placement. You can install a boiler room almost anywhere: in the basement or attic space, in a specially made extension.
In the case of organizing a boiler room on the roof - a huge advantage cascade of wall-mounted boilers in front of stationary floor-mounted ones is their low weight and ease of delivery to the installation site. There is no need to use special cranes to lift equipment during installation or dismantling. There is no need to disassemble the roof when replacing the boiler. Faulty boiler components are replaced on site. The light weight of the equipment and its placement on the wall help avoid unwanted loads on the building’s floors. Retraction flue gases when using boilers in the “turbo” version, it is possible directly through the wall on which the boiler is mounted. This allows you to save on the construction of an expensive stainless steel chimney. Indisputable dignity is the automatic regulation of the boiler room operation. The programmer provides control in accordance with the room temperature set for a given period of time. He attracts to work required amount boilers from a cascade and for such power as is really necessary. The absence of the “human factor” eliminates management errors. In general, a universal building climate control system is created. When the temperature in the room increases above the set one, the programmer turns off the operation of the boiler room, and if necessary, the thermostat of the air conditioning system turns on the air conditioning system. If the temperature drops, everything happens in the reverse order. Boiler room control devices allow the dispatcher of a service organization to see the current state of all equipment from his computer via a modem.
Termona-Bel company is official dealer Czech company Termona in the territory of the Republic of Belarus. The main activities of the Termona-Bel company are wholesale and retail trade in boiler rooms, training of interested specialists, installation and commissioning of boilers, warranty and service maintenance of boiler rooms, supply of spare parts for boilers and other activities aimed at promoting equipment in the territory of the Republic of Belarus.
The main advantages of cascade boiler houses based on THERM boilers can be briefly formulated as follows:
profitable investment;
economical operation due to wide range smooth power modulation (minimum threshold from 20% when installing 2 boilers and from 3% when installing 16 boilers);
full automation of control;
weather-dependent regulation;
remote control and control of the boiler room operation via a programmer or PC;
no need to maintain full-time workers in the boiler room;
high operational reliability due to the operation of several boilers in one system;
increased service life of boiler equipment;
simplicity and clarity technical solution;
ease of installation and commissioning;
simple and intuitive controls;
small footprint;
use of the floor for other components of the boiler room;
convenient connection of external tanks for DHW preparation;
the possibility of installing a high-power boiler room without installing an expensive chimney;
careful attitude towards environment.
Right choice a heat source will help save a lot of money while maintaining the required comfort. When comparing the economic indicators of exploited residential buildings and other facilities before and after installing Therm cascade systems, users often achieve incredible energy savings of up to 40% per year, so the return on investment is very quick and obvious!

As a rule, gas boilers in private homes are connected to one circuit. But this connection method has its drawbacks. It is much more effective when the system involves the use of several devices. The boiler piping scheme itself in this case can be cascaded.

Features of cascade connection

When gas boilers are connected to the heating circuit in series and form stage by stage, this is very convenient. At the same time, the control of the cascade cycle is general, and the owner can independently configure the system parameters based on the conditions. While other parameters are adjusted automatically. Experts call this configuration method flexible.

Gas boilers connected according to the cascade principle can be used to solve heating issues in residential buildings with a total area of ​​no more than 500 square meters. And although these figures are not mandatory for use, the owner independently decides the advisability of installing an additional boiler if the area to be heated is larger.

In any case, gas boilers connected using the cascade principle are very efficient to use. Those who install them will be able to feel this very soon.

What is needed for cascade connection

If you plan to connect gas boilers using a cascade type, you will need to decide on your own optimal scheme and calculate its parameters, taking into account all professional assessments of important factors. For example, turning on boilers may be possible in a sequential way, without additional equipment, only if the pump of each gas boiler can pump coolant through the heating circuit. For a small residential building this is quite enough.

But, if gas boilers are used for a large building consisting of several floors, then it is necessary to use a special hydraulic separator. This will optimize financial costs, guarantee higher comfort and rational consumption of blue fuel.