Advantages and disadvantages of a gas-electric combination boiler

To keep a private home warm even in the coldest winter, a boiler room is needed. Large enterprises manufacture heating equipment that runs on different types of raw materials. An electric gas boiler, which combines the 2 most common types of resources in one, is becoming increasingly common among owners. This increases the reliability and uninterrupted heating of the premises.

Combined gas-electric boilers

To avoid ending up in an unheated room in cold weather, many owners buy 2 separate devices for a private home. However, such a system requires a lot of money and a lot of space to install. Therefore, a gas-electric unit, which is more compact and versatile, is preferable.

Application

Such a heating device can heat a house and perform several other functions. The main ones will be:

• maintaining the required temperature in the greenhouse;
• heating water in warm pools and floors;
• heating a bath or sauna;
• If a 2-circuit system is installed, it is possible to organize hot water supply at home.

Design and principle of operation

Boilers, in which gas is burned as fuel and electricity is connected, operate according to several schemes:

1. In one case, the role of the main apparatus is played by an electric heater, and the gas component comes into operation during a power outage or to increase the power of the boiler room.
2. If a gas boiler becomes the dominant heater, then the electric one is considered a backup. Such equipment is installed for heating large houses.
3. There are boilers with 2 heating elements working together. They are the most economical and efficient.

The principle of operation of such a device is simple - the coolant is heated by electric heating elements or a gas burner, which is installed separately using special fasteners that eliminate welding. The transition is carried out manually automatically using a program-controlled unit when the temperature drops below the set one. Some models are equipped with a tank for storing heated water used to organize hot water supply.

To speed up the circulation of the coolant, an electric pump is additionally installed. In this way, the cost of heating the house is reduced, but the autonomy of the entire system is eliminated, because Without electricity, the unit will not function.

Possibility of implementing joint connection

Designing a conventional gas-consuming heating system is not so easy. That is, it is easy to create a working scheme, but getting it approved is problematic. The situation with electric boilers is less dire in terms of costs, time and problems with obtaining papers approving the procedure.

And here is the combination of 2 different fuel units. It would seem that you won’t run into problems and will have to go through the authorities for literally years to get permits. But that's not true.

There are no restrictions on the joint use of gas and electric boilers in regulatory documents. However, it is still necessary to coordinate such a project with the gas service and obtain permission if your use of electricity exceeds the established limit in the total capacity of the equipment

In fact, building regulations are quite favorable to such schemes. To be more precise, there are no prohibitions.

Energy and fuel consumption meters are different. Resource consumption is not exceeded, an explosive situation is not provoked - install boilers in compliance with standard standards and installation instructions for each. There shouldn't be any problems.

We remind you that the installation of gas boilers should be carried out in accordance with SP 402.1325800.2018 (and this document is mandatory and not advisory).

Advantages and disadvantages

After assessing the characteristics of boilers operating on gas and electricity, the following advantages are noted:

• small dimensions, not exceeding the size of 1-fuel models;
• prices for combined equipment are lower than for 2 separate devices;
• Efficiency reaching 98%;
• economical use of resources;
• low power of heating elements, heating an area of ​​100-200 sq.m;
• no harmful emissions;
• 2-circuit models can supply hot water to the house;
• low connection and installation costs.

Among the shortcomings are noted:

1. Low level of automation.
2. The need for a 3-phase network at the connection point.
3. Approvals from supervisory authorities are required.
4. Annual technical inspections by certified specialists.
5. Removable burners are noisier than standard burners installed in gas boilers.
6. Considerable cost.
7. Limited selection of models.
8. Additional costs for a gas burner, which is not included in the package.

SUMMARY

Every connection scheme, whether parallel or serial, has a right to exist.

The question is - how can you effectively and competently organize the linking of boilers for working in pairs in parallel or in series!?

The answer is that in each individual case, a different connection method will be appropriate. And the main factors that will influence the choice of boiler connection type are:

The ratio of thermal and energy parameters: (20

40) L /1 kW (the ratio of the total volume of system coolant per 1 kW of boiler power);

• Physical possibility of implementing one or another project;
• Financial capabilities to implement option 1 or 2.

Here you will learn:

Nothing prevents you from assembling the heating system yourself, but this requires certain knowledge. It is not enough to hang a heating boiler on the wall - you need to connect batteries to it. Installation of the harness will also be required. It will help make your heating system more efficient, safe and balanced. The heating boiler piping diagram includes many elements. Let's find out what these elements are and what they are needed for.

Varieties by number of circuits

This is the main technical feature of any boiler. The choice of model and method of operation of the equipment depends on it.

Single-circuit

This technique is intended only for heating water circulating in the heating system. Its power is enough to heat a large home.

To organize hot water supply, you will also need to buy and install a boiler.

Dual-circuit

An additional heat exchanger installed in gas-electric boilers solves the problem of supplying the house with warm water. If the power of the unit is sufficient, then several water points can be installed. To avoid a decrease in the temperature of the liquid during transportation, the taps should be installed close to the heater.

Such a boiler has several advantages:

1. Low gas and electricity consumption.
2. Simultaneous heating of water for heating and water supply.
3. The cost is lower than that of a single-circuit device and a boiler combined.
4. Installation in a separate room, as well as in the kitchen, is allowed, subject to installation rules.

Some of the inconveniences are:

• the need to balance the consumption of gas, water and electricity;
• if the liquid pressure decreases, then the released heat is spent on heating, i.e. the air temperature in the room rises;
• when the pressure changes, the equipment needs to be reconfigured;
• due to the scale that forms, periodic maintenance of heating elements is required;
• When using hot water for a long time, its temperature drops.

How to significantly save fuel to reduce costs

Each owner has a real opportunity to reduce the cost of electricity or blue fuel, even if the device does not provide automatic mode switching. To achieve significant savings, you will have to separately purchase a thermostat and install it on the equipment.

A room thermostat is usually programmable and during its operation it is guided by the air temperature in the room. For normal operation and performance of the function specified by the thermostat, it is necessary to program the settings not only for the next day, but also for the entire week in advance.

Saving fuel resources when heating your home Source chiamamicitta.it

If it is a working day and the owners are absent, then the temperature limit is set to 15 degrees. During sleep, it is rational to set priority to 18-19 degrees. By specifying these parameters, the level of comfort will not decrease, and fuel consumption will noticeably decrease. This can be determined by the amount of utility bills.

Basic criteria for choosing a unit

When purchasing a boiler that runs on gas and electric energy, you need to take into account several nuances:

1. It will be necessary to define the tasks that the equipment will perform, i.e. calculate the required functionality.
2. Availability of energy sources. If the house is located in a non-gasified area, then purchasing a device that consumes gas is pointless.
3. The dimensions should be selected according to the dimensions of the room in which the boiler is supposed to be installed.

Required power

This is the most important characteristic of any heating equipment. Combination units up to 100 kW are available for sale. However, you do not need to purchase the most powerful unit. Boilers up to 50 kW are equipped with all necessary functions. If a private house is located in central Russia and is made with 2 bricks, and the ceilings in the rooms are 2.7 m, then for every 10 sq.m. you will need 1 kW.

In addition, experts recommend adding 20-25% after calculating the full power in case of extreme cold.

If the owner opted for a 2-circuit option, then a reserve of 10-15% should be provided for heating.

Characteristics

Gas-electric boilers are cheaper due to the absence of two different fireboxes.
Gas-electric heating devices regulate the operating mode (on, off) automatically. In this way, the required temperature is maintained in the room, and resources are used as economically as possible.

Combined heating devices have the following characteristics:

• Small sizes. The design of such units includes oversized combustion chambers for burning gas and heat exchangers with a built-in heating element.
• Low level of electrical energy consumption. The boiler mainly operates on gas, and the electric heater starts up if necessary for prompt heating of water, as well as in the absence of a gas mixture supply.
• Reasonable price. It is formed due to the absence of a separate chamber (combustion chamber), since the heater is built into the heat exchanger. In equipment where there is no secondary circuit, an option is planned for the possible connection of a water heater.
• Heating elements with low power. Most models on sale only support the specified temperature value. Water heating heating elements begin to work when the electric operating mode is started.

Gas is considered an economical type of fuel, which cannot be said about electricity. In this regard, for heating houses in areas with a poorly developed gas supply, it is better to find a boiler option that runs on a different type of fuel.

An electric gas boiler costs on average 70-80% higher than a pure gas boiler. But since the installation of such a unit is cost-effective, its cost is fully recouped within 3-4 years.

Popular makes and models

The choice on the heating equipment market is wide and multifaceted. However, in the segment of boilers running on gas and electricity, only a few companies compete with each other. Among them there are Russian and foreign manufacturers.

"Hercules"

Equipment of domestic design and production is intended for operation in houses with an area of ​​up to 300 sq.m. The catalog presents various modifications with a wide range of functions. There are boilers with 2 circuits, in which the part intended to provide housing with hot water is coated with a special composition. This technology increases the duration of trouble-free operation of equipment.

Navien

Products of the Korean brand are found in various regions of Russia. Boilers of this brand have been trained to take into account the specific climate of our country. With the help of a built-in stabilizer, they do not respond to voltage surges. Special sensors allow the boiler to operate when the pressure in the gas pipeline changes.

The owner can set the desired modes manually or using a program with an electronic unit. A remote control is included for control.

“Teplodar Kupper OK 15”

This is the most famous and popular model of a gas-electric boiler designed for a heating system in a private home. Simplicity and reliability are combined with a low price. The inclined firebox allows you to quickly and easily clean the interior. The Kupper OK 15 boiler is equipped with electric heaters with a power of 6 kW. The attractive appearance allows you to install the boiler in a kitchen with modern renovation and household appliances. The build quality is at a high level.

There are several disadvantages:

• narrow firebox opening;
• the heat exchanger is made of steel without anti-corrosion treatment, which reduces its service life;
• low efficiency compared to other models.

“Karakan 20 TEGV”

The next Russian brand representing a combination boiler for any type of fuel. It is small, with a wide firebox and factory-installed heating elements. The boiler is not equipped with a gas burner. The disadvantages include a rusting heat exchanger, an efficiency of no more than 75%, and the impossibility of installing a closed-type heating system, because the maximum working pressure is low.

STS v25 fg

An expensive Swedish-made boiler can operate on natural or liquefied gas, electricity, diesel fuel, fuel oil, wood, coal, peat, and pellets. The body is made of steel, and the firebox is made of cast iron - a heavy, fragile, but non-corrosive, durable material. Electric heaters with a power of 15.75 kW are installed inside.

The operation of the boiler is regulated automatically.

Separately, the model is equipped with additional electronic units to control the equipment depending on the outside air temperature. The second circuit is coated from the inside with an anti-corrosion compound.

The heated area is 500 square meters. m. This size is provided with a power of 45 kW. In addition, water with a volume of up to 730 l/h is heated in the heat exchanger.

Among the advantages of the boiler:

• easy access to the firebox for cleaning;
• minimal soot emission;
• control of exceeding the maximum permissible parameters;
• you can turn off the pump or burners as needed;
• Efficiency > 90%.

The disadvantages were the high cost, height of about 1.5 m and weight of 385 kg.

Hydraulic arrow in a parallel connection system

A hydraulic arrow is a device that provides hydraulic isolation of flows supplied to individual circuits of the heating system. It plays the role of a buffer tank, receiving the flow of coolant heated by the boilers and distributing it to consumers in a branched system.

Often the volume of coolant required for them differs, the speed of movement of the heated water and its pressure differ. And in the situation under consideration, the movement of heated water from each of the boilers also stimulates its own circulation pump.

When the powerful pump is turned on, the coolant is unevenly distributed throughout the circuits. So, the task of the hydraulic gun is to equalize this pressure. Due to the fact that there is virtually no hydraulic resistance inside it, it will freely receive and distribute coolant flows from both boilers.

Let’s figure out whether it is really necessary in a parallel system for connecting 2 boilers, especially since if you buy and install a hydraulic separator with the help of a specialist, and not with your own hands, the total amount will be unpleasantly surprising.

The device is a piece of pipe with pipes, hollow or with filter meshes to remove bubbles and filter out incoming contaminants. It can be placed in any position, but more often vertically, with an air vent on top and a shut-off valve on the bottom for cleaning. A hydraulic arrow is installed between the boiler and heating circuits

In the classic connection scheme, a hydraulic separator is usually not required, since the conflict of 2-3 pumps can be equalized without this device. Accordingly, if you have 2 boilers that are used exclusively as a backup and there are no more than 3-4 pumps in the system, there is no particular need for it.

But if there are more forced circulation circuits or heating boilers operate simultaneously at full power, it is best to install this device. Again, it is unknown whether you will use the second boiler permanently or only in backup mode, so it is better to be safe.

Device prices: summary table

In order for the buyer to quickly choose an option that suits his needs and income level, the offer of trading enterprises is as follows:

Electric gas boiler installation and safety precautions

Before specialists authorized to work with gas equipment begin installation, it is necessary to check whether there is draft in the chimney. Next, you need to carry out the following steps step by step:

• install the boilers included in the delivery set according to the support level;
• install water and gas filters;
• connect the device to the main gas pipeline;
• connect the power cable;
• check the tightness of the heating system and clean it as necessary;
• connect the boiler to the pipeline;
• perform a test run;
• If problems occur, eliminate them;
• configure settings.

Rules for safe use require that the room where such equipment is installed be equipped with supply and exhaust ventilation.

Power Supply Requirements

Such a consumed load on the electrical network requires a dedicated line to connect the converter.

The power cables to it are laid directly from the metering device (electricity meter). For emergency or scheduled generator shutdown, automatic switches are used, which in parallel act as a fuse in the event of a short circuit.

It is possible to connect models with a power of up to 9 kW to a single-phase network; more powerful equipment operates on three phases.

Please note: the boiler must be connected to a grounded electrical network

Operating the device

For long and safe operation of a boiler that consumes electricity and gas, several rules must be followed:

1. Sufficient traction must be ensured during use. To do this, you need to accurately select the cross-section of the chimney.
2. The chimney should be insulated with non-combustible materials. This way you can avoid fire from touching flammable parts.
3. During periods of intensive use of the unit, it is necessary to clean the ash pan as it becomes dirty.
4. To protect the floors from sparks, a sheet of metal must be laid in front of the firebox.

Following these simple steps will allow you to enjoy the warmth during the most severe frosts and allow the whole family to enjoy hot water all year round.

Despite the availability of combined units, users still ask the question “electric boiler or gas boiler, which is better?”

Closed system with heat accumulator

A closed heating system does not require the installation of an expansion tank, so the installation process is greatly simplified. Most often, gas boilers are equipped with an expansion tank and a safety valve.

To properly assemble such a heating circuit, you must follow certain instructions:

• A tap and a pipe leading to the heating devices are connected to the supply fitting of the gas boiler.
• A pump is installed on this pipe for forced circulation of the coolant. It should be placed in front of the radiators.
• Each radiator is connected in series.
• A pipe goes from them to the heating boiler. At the end of the pipe, at a short distance from the unit powered by a gas cylinder, a shut-off valve is installed.
• The supply and return pipes are connected to the pipes going to the heat accumulator. One of the tubes is connected in front of the pump, the second tube is connected behind the heating devices. Each tube is equipped with a tap; the tubes that were previously cut in before and after the heat accumulator should also be connected here.