Gas boiler for an open heating system

Externally, outdoor gas boilers are metal boxes with water and gas piping and cable runs to them. The body in which the heat exchanger tubes are located is heavily insulated with mineral wool or other insulation. The front and rear metal walls are doors, but all panels are removable for easy access to the interior. Despite this box is sturdy, vandal-proof, surrounded by fencing, especially if it is outdoors and not just outside the house.

Additionally, the unit can be equipped with:

• flue pipe for draining the combustion products and blowing air;
• A light and sound fire alarm (including tamper-proof)
• a radio transmitter to report abnormal situations.

Most low-power gas boilers do not need a reinforced foundation, and can be set level in a chosen location, as recommended by the unit manufacturer.

Design and principle of operation

Inside the body there is a furnace with a burner and a tube heat exchanger with increased heating area due to the fins. Twin boilers have two furnaces with two heat exchangers and burners. In case of lack of power add another device and make tying.

The principle of operation, as in the classic gas boiler. a simple: the gas mixed with air, fed to the burner. a horn with lots of holes, breaking up the flow of the mixture for complete combustion, the flame heats the heat exchanger pipes, and the circulating pump directs the coolant to the heating system. For the air flow and removal of products of combustion responsible chimney. Automatics regulates the gas flow rate and, if necessary; switches on the forced air blowing. The control panel with mode selection and a processor that monitors the weather outside, the temperature condition in the building and the correspondence of the combustion modes to the set parameters, is usually located in the building.

The PRC cabinet in its basic configuration contains:

• pipeline valves;
• safety valves;
• strainers in the pipes;
• INSTRUMENTATION;
• basic set of sensors;
• auto ignition of burner.

Automatics, which allows you to regulate the flow of fuel and adjust the combustion, three-way valve with electric drive, various alarm devices, circulation pump, unlike models mounted in the house, are most often presented as additional options and greatly affect the price of the device.

The method of removal of combustion products depends on the design of the combustion chamber. For an open fireplace as a chimney is an ordinary chimney, for a closed. coaxial (pipe in pipe). On one tube of such a chimney to the combustion chamber air enters the burner, the other from the furnace leaves the smoke. The chimney is subject to the requirements of SNIP 2.04.05-91 and DBN B.2.5-20-2001. The following design standards are mandatory:

• The height of the chimney must provide a good draft and prevent smoke in the residential area;
• on the top of the mandatory deflector, which prevents moisture and debris in the chimney;
• Vertical deviation should not exceed 30 degrees;
• The chimney is made of gas-tight materials and carefully sealed;
• At the bottom of the structure should be a condensate drain.

The material for the chimneys can be any of the cheapest. asbestos cement pipes to stainless steel or ceramics, but the requirements of the regulations have to fulfill for private homes and industrial buildings.

Start-up of the PRC is carried out after the installation of the heating system and DHW, pressure testing of the pipe network with 1.25 of working pressure and testing of the valves. Then the prepared system is filled with coolant and the tap on the gas line is opened. According to the manufacturer’s instructions, ignite the boiler, when the desired temperature is reached, the circulating pump turns on and the coolant will begin to move through the pipes.

Installation requirements

Despite the fact that the outdoor gas boiler equipment is produced in series, complies with all specifications and does not need an equipped room and operating personnel, its installation requires the implementation of organizational and technical measures.

In order to assess your ability to independently obtain permission to connect to the gas mains, it is desirable to study the regulations:

This will allow you to speak with the gas company in their language and lead to the understanding that there are many nuances ahead, but the gas service can refuse to issue the TU only because of the lack of technical possibility of connecting the facility (Decree 1314 of 2013).). The refusal can be justified after checking the capacity of the PRC and the lack of a connection point (GOST R 54961-2012).).

The key point is. Here is a decision to either do it yourself: to obtain the TU, order a project in a licensed organization, buy the equipment, find a mounting organization for installation and commissioning, while retaining the warranty provider and the subsequent service, or enter into a contract with a manufacturer or dealer of the PRC for the entire set of organizational and technical measures. Most likely, in the long run, it will be faster and cheaper.

Technically, the installation of gas outdoor boiler comes down to following the recommendations of the manufacturer of the equipment. However, keep in mind that unauthorized connection and installation of a PRC is not legal or safe. To install the boiler small enough flat area above the level of the possible snow cover, permission to install and fencing. For powerful boilers may need a foundation, as required by the technical documentation of the equipment.

Can one-circuit boilers be used to heat water for daily needs?? Yes, many modern models allow this. But you have to buy a boiler. It must be connected to the boiler, and in any case the entire process, starting with the selection of the appropriate model, should be entrusted to a specialist. Most consumers, however, in such situations, usually just take a separate boiler, working on electricity.

For example, for quick connection of the boiler, you can pay attention to the boiler kit module from GIBAX. It is used to connect electric storage vertical and horizontal water heaters with a diameter of 1/2″ connection to the water supply system. Has a mode of disconnection of the heater from the water supply, and the mode of water drainage with air suction for preventive maintenance.

Which option is better?? Mainly prefer two-circuit boilers: they are more convenient. But note that such models are always more expensive. The choice, in any case, depends on the consumer.

Floor standing and wall hung boilers

Boilers can still differ in location in space: there are heating boilers for a private home gas floor and wall-mounted. The latter take up less space, they are generally more compact. In addition, they can be installed almost anywhere if certain requirements are met. Also for wall hung boilers you do not need to organize a separate chimney: usually everything is solved by the branch pipe, through which the products of combustion are evacuated.

What is the difference between floor gas boilers for heating the house (they are officially called so)? They tend to be more powerful and noticeably heavier. These models require more space: first, for the bypass, secondly, for the chimney. Not to mention the set, consisting of a single-circuit boiler and boiler. In addition, such instances are quite noisy, so they are usually installed in a separate room (boiler room).

Choosing the best solution depends on what you need in a particular case. That is, for an apartment or a small cottage, the best gas boiler for heating. wall mounted. For a large house. floor.

But when buying you need to consider another factor that can become critical: the dependence on electricity. Floor standing boilers are stable in this respect. Even if there will be no electricity in the house, the heat is still there. However, now more and more often produced by models with automation, which removes this advantage. Nevertheless, it is possible to find options.

And all floor models depend on the voltage: surges in the network can cause equipment failure. Of course, no one prevents you to put a stabilizer. But first of all this is an increase in costs. Secondly, the question of cutting off electricity remains.

In general, both floor and wall-mounted products have their own advantages and disadvantages. Therefore, to understand how to choose a gas boiler for a private home, it is worth depending on the specific room, the quality of electricity and the financial capacity.

Boilers with open or closed combustion chamber

Boilers can be with an open or closed combustion chamber. The first ones take in air from the environment. Therefore, the issue of ventilation in this case becomes critical.

There is a risk that there will not be enough oxygen as a result. These models are considered to be obsolete in the EU, they are abandoned everywhere due to increased safety requirements.

At the same time, open combustion chamber boilers have a simple design. Therefore, they break down less often (if compare models in the low price category), cost cheaper, installation is simpler. And it is not very difficult to find specialists to deal with them.

Variants with a closed combustion chamber are considered more modern. They are safer, but require the installation of a chimney. However, this is the case when you can once spend money to buy an expensive model and for installation, and then do not worry that the room will not be enough oxygen. Or that someone will suffer from poisoning by combustion products, as is the case with problems with boilers of the first type.

But models with a closed chamber have their own disadvantages. For example, you have to install a ventilation system that needs electricity. Which, firstly, makes such a design dependent (along with the light will be lost and the heat), and secondly, increases the cost of providing the house.

The easiest way is to choose boilers with a closed combustion chamber with a pipe extending outside. But for the installation of this model is not always technically possible. So to say in this situation, what boiler to choose for the house, it is difficult. We need information about the facility, about whether it is possible to organize a separate room or take the pipe outdoors.

Basic nuances of choosing a gas boiler

Lack or constant interruptions of centralized heating and hot water supply make the owners of cottages and city apartments to create their own autonomous system.

Their main element is a boiler that heats the coolant for the heating system and water for household needs by burning fuel.

Choice in favor of gas equipment due to economical use of gas as fuel. All other options of burning fuel are more expensive or provide much less heat.

Plus, modern heaters of this type do not require constant supervision. You connect the installation to the main pipe or cylinder, and it works flawlessly, as long as there is something to burn.

However, in order for the gas boiler to function properly and in an optimal mode, it is necessary to choose it intelligently when buying and regularly maintain after connection.

There are a lot of different in functionality and special modules inside the models of this equipment. To buy the heating unit for gas should be thoughtfully approached.

Criteria for choosing a gas boiler are many, but the main ones are:

• Power issued by the device.
• The solution (the number of loops, type of enclosure and material of the heat exchanger).
• Place for installation.
• Automatics for safe operation.

All these issues are closely related to each other. Lack of space for a large unit or the desire to mount a device with an aesthetic appearance in the kitchen, force to choose a wall-mounted model of less power than the floor version. And the need to heat hot water for a washbasin and shower forces to look for a boiler with two circuits.

System equipment and operation principle

In the water heating system, the intermediary in the transfer of thermal energy from the boiler system to the radiators is a liquid. The circulation of the coolant can be carried out over long distances, providing heating of houses and premises of different sizes. This explains the widespread use of water heating.

The functionality of an open heating system is possible without the use of a pump. Circulation of coolant is based on the principles of thermodynamics. The movement of water through the pipes occurs at the expense of the difference in the density of hot and cold fluid, as well as due to the slope of laid pipes.

Indispensable element of system. an open expansion tank in which the surplus of the heated coolant. Automatic stabilization of the fluid pressure due to the reservoir. The tank is installed above all system components.

The whole process of the “open heating supply” can be divided into two parts:

• Delivery. The heated coolant moves from the boiler to the radiators.
• Return. The surplus of hot water goes to the expansion tank, cools down and returns to the boiler.

In one-pipe systems, the function of supply and return performs one line, in two-pipe schemes supply and return pipes are independent of each other.

The simplest and most accessible for independent installation is considered a one-pipe system. The design of the system is elementary.

The basic set of one-pipe heating system includes:

Some refuse to install radiators and place the pipe diameter of 8-10 cm on the perimeter of the house. However, experts note that the efficiency of the system and convenience of operation with this solution decreases.

The two-pipe heating variant is more complicated in construction and more expensive. However, the costs and complexity of construction are fully compensated by the elimination of the standard disadvantages of one-pipe systems.

Heat carrier with an equal temperature is delivered almost simultaneously to all appliances, the cooled water is collected in the return line, and does not flow into the next battery.

Open heating system. types, schemes, pros and cons

The possibility of using water as a coolant allowed mankind to invent efficient heating of their homes. Open heating system. a classic option, which is still popular, thanks to the simple principle of operation and the minimum number of necessary devices. In this article, the master plumber will tell you what is an open heating system, its pros and cons.

In the water heating system, the liquid is a means of transporting heat energy to the devices that transmit heat to the air. These devices can be radiators or the pipe circuit itself inside the floor.

One boiler is enough even for heat supply of several rooms that are at a distance from the heat generator, it all depends on its capacity. In addition, by changing the number of radiators, you can evenly heat the rooms of different areas. This is the advantage of water heating over the installation of a conventional oven, which can only heat the space around it.

Fluid movement in the circuit can, due to the laws of physics, be by gravity: the heated medium has a lower density than the cooled one. In addition to the principle of thermodynamics, operation is provided by the installation of pipes under a certain slope. A circulation pump can also be used to increase efficiency. Many people mistakenly believe that the pump. an attribute of the closed system only: the open circuits are also allowed forced circulation of coolant.

An open heating system is characterized primarily by an open expansion tank. It is an ordinary cylindrical or rectangular shape vessel. The reservoir allows you to automatically stabilize the pressure in the system.

And in order that the liquid does not pour out on the principle of communicating vessels, the expansion tank is mounted in the highest point of the circuit. The tank also serves as an air valve: through it air from the system is released into the atmosphere (when it is filled and operated).

Home heating is provided by the following principle:

• Supply. coolant is heated in the boiler and moves to the radiators. cooled liquid in the radiators tends to “go” to the bottom point and due to the slope of the pipes gets into the boiler.

Installation of a circulation pump makes the process more intense, but the principle of operation does not change from this.

Such schemes of water heating are divided into types depending on the way of circulation and delivery of the coolant to the radiators with its subsequent return back to the boiler. The heated water can move along the lines in two ways:

Due to the peculiarities of design there is almost no excess pressure in the open heating system. At the highest point it is equal to the atmospheric pressure, and at the lowest point it increases slightly because of the hydrostatic action of the water column. The value of this head is small, which makes it possible to organize the natural circulation of the coolant. The principle is based on the fact that the coolant has a different density at different temperatures, and therefore has a different mass. Example: 1 cubic meter of water at t = 40 ° C weighs 992 kg, after increasing the temperature to 60 ° C weight of 1 cubic meter drops to 983 kg.

The difference seems to be insignificant. Nevertheless, it allows the cooled coolant with a low temperature to displace the lighter hot water from the boiler. Natural (convective) circulation occurs in pipelines, and such systems are called gravitational, because movement in them occurs due to gravity. In gravitational systems mains are made with steeper slopes and larger pipe diameters, the speed of flow of the coolant in pipes and radiators is low, only 0.1-0.3 m/sec. But such schemes are fully energy-independent, provided that boilers for open heating system, not requiring electricity, work together with them.

In order to increase the speed of water running through the pipes and reduce the warming up time of the premises, a pump is built in the pipe from the boiler. It forces the coolant to move at a speed of 0.3-0.7 m/s, which causes the heat transfer to be more intensive and all branches to warm up more evenly. Due to the presence of a pump, the distance between the heat source and the radiators can be increased both in length and height.

To ensure that the heating in a detached house does not stop with a power outage, it is usual to install a circulation pump on the bypass.

The installation of a pump unit allows you to create a slight excess pressure in the heating system, allowing the coolant to flow well into the radiators. This clearly increases the efficiency of the system as a whole, although it makes it dependent on the availability of electricity.

• The total area of the premises, where the water heating should be carried out. If the value is less than 60 square. м., A system with natural flow of coolant (gravitational) is enough.
• Floors of the building, height of ceilings. For gravity system will require dispersed flow from the boiler to eliminate the formation of air bubbles in the circuit. they prevent the normal movement of the fluid and heating efficiency.
• Calculated thermal operation of the system. If you intend to use low-temperature heating, the open system must put the circulating pump. Without it there will be no movement of the coolant, as only the thermal expansion of water at 45-60 ° C will not be enough for natural circulation.

The water heated by the boiler can be delivered to the radiators and returned to the boiler in different ways. According to the ways of delivery of the open heating system is:

In a one-pipe system, the coolant supply is organized through a single large-diameter line that passes by all radiators. The appliances are connected to it with both spigots, taking water from the pipe and giving it back to the same pipe. The distribution main can run horizontally within 1 floor (“Leningradka”), as shown in the diagram:

The system can consist of vertical risers penetrating several ceilings, and the radiators are connected to them floor by floor. A typical one-pipe forced circulation heating scheme with vertical risers for a two-storey house is shown in the picture:

Along with the apparent simplicity of such schemes, single-pipe systems have a significant disadvantage: each successive appliance receives increasingly colder water. This imposes a limit on the number of batteries, for efficient heating their number should not exceed 5. Another thing is a two-pipe system, where the heat carrier comes to the radiators through one main and goes through the other. In this case, the length of the branches and the number of batteries on each of them can be much more.

In addition, the flow of the coolant can be organized in one direction so that it passes the same distance through all radiators. Such a flow system with circulating pump is shown in the picture:

Two-pipe system makes it possible to deliver water with the same temperature to all, even the most remote radiators. Scheme is a little more complicated in installation, but easier to design and more reliable in operation.

Arranging the heating of the house, you must take into account that the open heating system has several features:

• Boiler (solid fuel, gas, liquid fuel) must be located at the lowest point of the line, and the expansion tank. at the very top.
• It is most convenient to place the expansion tank on the insulated attic, if the roof is cold. insulate the tank itself and the pipes.
• The fewer turns and connectors in the line. the more efficiently the coolant moves in natural circulation.
• The speed of the coolant in the gravitational system does not exceed 0.3 m/s, so it is important to monitor the temperature of the fluid in the boiler, do not let it overheat and boil. this will damage the pipes and heating devices.
• Before the onset of cold weather, the water from the unused heating system is drained, so that the pipes and the jacket of the boiler will not burst when the liquid freezes.
• In the expansion tank regularly requires the addition of water, as it eventually evaporates, and the lack of coolant will lead to the formation of air s and stop the system. You can organize a node make-up or pour manually from a bucket. it is easier in a small detached house.
• The open heating system dictates the use of water as a coolant. This is due to the fact that antifreeze refers to toxic substances, and its fumes from the open tank are harmful to humans. In addition, it will have to be replenished regularly, increasing the cost of heating. If the heating is supposed to use irregularly, but you want to avoid the hassle of constantly draining the fluid from the circuit, it is allowed to fill antifreeze, but in this case, the expansion tank is supplied with a cover with a small hole to reduce the speed of evaporation of antifreeze.
• The key stage of arrangement of heating gravitational type. design, because it is important to correctly perform the calculation of the cross section of pipes and pipeline slope. The relevant standards are specified in SNiP 2.04.05-91. The length of the circuit should not exceed 30 meters, on the horizontal sections of the line pipes are installed with a slope of not less than 2-3 mm per meter of length.

When arranging heating in a private home, many people prefer the classic version of the system, which uses an open expansion tank, despite the growing popularity of more advanced systems of closed type. This choice is due to the advantages that have open systems for heating the house, they include:

• Energy independence. For areas with unstable electricity supply is relevant to the issue of heating without the use of equipment that consumes electricity. In addition to the arrangement of the open system is important to use an energy-independent boiler unit.
• Reliability. This is a major plus. this option of heat supply has proven its functionality over decades of operation in a variety of conditions, including in regions with a harsh climate. In fact, the reliability of open systems is reduced to the reliability of boilers, because there are no more elements that can fail. It is important only to choose carefully the heating devices and elements for the installation of pipelines. their service life depends on the duration of operation of the system.
• Simple scheme. No complicated components, the installation can be carried out independently.
• No debugging and adjustment required. After installation is complete, the circuit is filled with water. If the heated coolant began to circulate, everything is done correctly.
• Quiet operation, no vibration (if the circulation pump is not used).
• Possibility to complement the energy-independent heating with a circulation pump, making a universal system and increasing its efficiency.

The disadvantages of operating an open-type heating circuit include:

• Limitation in use. This system is not suitable for large houses. if the length of the horizontal pipeline exceeds 30 meters, the value of the hydraulic resistance in the pipes exceeds the head of the flow of the coolant, ie, natural circulation is not possible, there will come a static equilibrium.
• Inertia. Without installing a circulating pump heating up the system (entering operating mode) will take a long time, since the speed of movement of the heated fluid is extremely low. For the same reason it is impossible to organize operational control of the indoor climate.
• Constructional nuances. To minimize the hydraulic resistance in the pipeline, it is mounted from pipes of different diameters (with distance from the boiler diameter should decrease, to maintain a normal speed of fluid movement), and this complicates installation and requires additional costs. larger diameter pipes are more expensive, you need adapters, etc.д.
• Installation peculiarities. It is imperative to observe the calculated slope of the pipes in each section of the line. even a single error can make the system unworkable or reduce its efficiency. In the latter case, to overcome hydraulic resistance will have to increase the operating temperature of the coolant, which leads to higher fuel consumption and increased financial costs for heating.
• Service. Because of the intense evaporation of hot liquid from the open expansion tank, you need to constantly monitor the water level and time to replenish it.
• Active metal corrosion. Through the tank in the coolant is constantly getting oxygen, which accelerates corrosion processes. It reduces the durability of the metal elements of the system, including the steel heat exchanger of the boiler unit.

In the story. How to properly install a pump on the gravity system

CENTRAL HEATING SYSTEMS. Gravity. Fully Pumped. Combi. Y Plan. S Plan

Open systems for home heating are an indispensable option for areas far from central utilities. In the presence of a stable power supply, this type of heating is chosen when there is a desire to minimize the seasonal financial costs of heating a small area of the house.

Is it possible to assemble an open heating system yourself??

With the installation of an open heating system does not need to have superpowers, it is important to carefully study such an issue as the scheme of work. First of all, install the boiler. It can be placed on the floor or suspended to save space. Boiler capacity should be chosen based on the area of the room you are planning to heat.

The second step will be the distribution and installation of radiators. Calculate their number based on the area of the room. One radiator can heat up to 1 sq.м. living area. You don’t want a radiator, mount a pipe with a diameter of 10 cm. It can be run throughout the house and back to the boiler. For better circulation of water, fix the pipe at an inclination. As for the tank, it can be installed on the return near the boiler.

There is another option for the installation of open heating. Open heating can be placed vertically, with the tank installed in the attic. To prevent the tank from being affected by temperature fluctuations, take care of its insulation.

Pay special attention to calculate the volume of the expansion tank. If you calculate incorrectly, you risk an explosion. The tank will burst from the action of increased pressure.

Talk about selecting parts for open heating:

• It is better to place the boiler in a separate building. There must be free access to the bypass pump for the circulation pump to work. Put some material on the floor that will not catch fire. You would better just concrete the floors. Measure the size of the room. Based on these calculations you can calculate the necessary boiler output. The boiler will be able to work both on gas and wood.
• It is better to choose steel radiators. They should be mounted so that they are at a distance of 5 cm from the wall. Radiators can be mounted under window sills. This way they protect the room from the outside cold, and act as a protective screen. From the floor at least 40 cm. To heat a room with an area of 15 sq. ft.м. You need a radiator of at least 100 cm.
• Pipes. In the old fashioned way used copper pipes. However, they have not justified themselves. Copper pipes are expensive and corrode quickly. The best option will be the choice in favor of plastic pipes. Their diameter is at least 32 mm. Calculate the length of pipes, taking into account that they go out from the upper part of the radiator and connect it with the lower part. The pipes are installed along the outside of the wall. There is no need to install them into the wall. Connect the pipes to each other using elbows. Also, do not forget to connect the boiler, expansion tank and radiators.
• Expansion tank. The expansion vessel should be positioned in the attic of the room or close to the boiler. The expansion vessel should not exceed 5% of the volume of the entire heating system. To heat a house in one floor, you better choose a tank of 8 liters. To make no mistake, buy a 15 liter tank.

Rating single-circuit gas boilers: Top 12 boilers 2021

Wall-mounted single-circuit gas boilers are a compact mini boiler room, all the equipment which is already located in one body and ready to go right after connecting to the heating circuit and the gas network. Single-circuit models are optimized for space heating, and for hot water preparation it is necessary to install a boiler of indirect heating in addition.

Small dimensions of the gas boiler allows you to install it in any convenient location, bringing the communications to which are implemented with the requirements of regulatory documents. The choice of heated area is limited line capacity wall mounted heating devices, the typical value of 24 kW. Prepared by engineers Teplomatica TOP rating single-circuit gas boilers, will help the untrained user to navigate the market better equipment for heating private homes.

With forced circulation

The scheme includes water pumps that make the water circulate forcibly. Pump circuit does not limit the use of heating schemes, the upper and lower coolant outlets, one-and two-pipe circuit is possible. Circulation pump is often installed upstream of the boiler and allows you to do without the organization of the slope of the pipeline.

The main condition of the scheme with forced circulation. uninterrupted power supply for the entire period of heating. The disadvantage of the system is its suffocation (usually at the beginning of the heating season).

Combined system

Combines the previous types, with its own features:

If the electricity grid is intermittent, the house is heated by natural circulation; the pump is activated if the house is to be heated quickly.

Once the installation of wall hung boilers or their floor standing counterparts is complete, the period of operational maintenance begins. To avoid breakdowns and emergencies, the equipment must be inspected at regular intervals. In addition to the gas unit itself, no less attention needs the piping of the heating system.

Often the cause of the accident is clogging of the pipeline accumulated on the inner surface of the pipe scale of salt. This problem is especially acute when hard water is used in the system. It can be solved by periodic preventive cleaning. by pumping special reagents into the pipeline.