There is a requirement of the rules: independent connection of the heating unit to the main gas pipeline is strictly prohibited. But the installation and connection of a double-circuit gas boiler to the heating system and to the electricity network of a private house is quite allowed. The main thing is not to make mistakes in the pursuit of savings. We will try to warn you from them.
Install the boiler correctly
In contrast to the installation of solid fuel and electric units, strict requirements are imposed on the installation and connection of gas heating boilers. The procedure is as follows:
- Contact your natural gas supply company for permission to connect to an external network. The company issues technical specifications (TU) for joining the highway.
- According to the issued technical specifications, the licensed company develops design documentation approved by the engineers of the gas supplier organization.
- After the approval of the project, the trained personnel of the company connects the gas-powered installation to the external network.
Prompt. When contacting the management organization, take the technical documentation of the private house and the passport of the purchased heater. The second moment: the employees of the "gas" office will probably tell you a suitable design firm.
Hence the conclusion: proceed with the installation and connection of a dual-circuit boiler with your own hands should be at the design stage, when the heating unit clearly allocated a place in the house. If it is delivered in violation of the rules, then the specialists of Gorgaz will refuse to connect the main pipe.
Although all the requirements for the placement and connection of the gas boiler must be known to the design engineer, you also will not hurt to familiarize yourself with the rules:
- room for the location of the heat generator: kitchen (if the power does not exceed 60 kW), a separate room on any floor (up to 150 kW), an attached or separate furnace;
- minimum height of the ceilings of the kitchen or furnace - 2 m, volume - not less than 7.5 m³;
- if two gas devices are installed (for example, a boiler + column), then 2.5 m overlap and a volume of 13.5 m³ are needed;
- ventilation: natural extract of air in the amount of 3 room volumes in 1 hour, for inflow to this amount add combustion air (the volume is indicated in the heater's passport);
- the walls of the furnace must be non-combustible or protected from fire and the spread of flame;
- the minimum allowable area of the transparent part of the windows is 0.03 m² for each cubic meter of furnace volume (called - an easily removable structure that flies out during a gas explosion);
- the passage in front of the thermal unit is not less than 125 cm, on the sides - 70 cm for maintenance;
- the distance from the boiler to the vertical chimney channel is not more than 3 m.
Note. Kitchen ventilation is provided through a window leaf plus clearance under the entrance door with an area of 0.025 m². Passages on the sides and back of the heat generator are made if necessary, maintenance, in front - is required.
When installing a wall-mounted gas boiler on a wooden partition, a sheet of non-combustible material is laid under the body:
- roofing steel 0.8-1 mm thick;
- asbestos 3 mm (unsuitable in the kitchen due to dust);
- basalt cardboard;
- mineralite slabs.
Protection should exceed the case dimensions by 10 cm, from above - by 700 mm, which is done in the photo.
The distance from the mounted heater to the nearest structures or cabinets is indicated by the manufacturer in the operating instructions, as shown in the diagram. The floor heat generator is installed on a non-combustible base, the wooden floor must be protected with a sheet of metal.
Tying wall models
From the lower part of the gas double-circuit boiler there are 5 fittings with an external thread, designed to connect the following lines (from left to right):
- Supply of heated coolant to the heating system.
- Hot water outlet directed to consumers (bathroom, kitchen and so on).
- In the middle is the gas pipe.
- Cold water inlet.
- Return pipe from the heating network.
The location of the nozzles on all outboard units is the same. If you are interested in knowing the reason for installing the fittings in this order, we suggest watching a video on the principle of operation of a dual-circuit wall-mounted heat generator:
Important notice. Five exits - not a sign of a boiler with two circuits. Manufacturers of hot water equipment often supply single-circuit heat generators with additional nozzles for connecting an indirect heating boiler, placed in the same order.
To do-it-yourself connection of the gas unit to the heating and power lines of a private house, prepare the following set of products and materials:
- ball valves with American ½ inch - 3 pcs.;
- the same with a diameter of ¾ ”- 4 pcs.;
- mesh filter for water and coolant (aka mud collector) - 2 pcs.;
- gas filter;
- expansion tank;
- pipe fittings - tees and elbows;
- three-core electric cable of the VVG brand with a cross-section of 2.5 mm²;
- 20-amp automatic bipolar circuit breaker.
This list is recommended for the poorest wall-mounted boilers equipped with an open combustion chamber. Products of the middle and highest price category, which are mini-boiler rooms, are equipped with their own gas filter and expansion tank.
It is recommended to compare the size of the nominal capacity of the heat generator with the amount of coolant in the heating system, guided by our instructions. In a situation where the pipeline network is too large and the tank volume is insufficient, an additional membrane tank must be installed.
Scheme of connection to the heating system
In fact, the binding of a dual-circuit heater is not a problem, there are only a couple of nuances, which we will consider further. One thing needs to be understood: a gas boiler is a reliable product in operation, for the entire period of operation it is unlikely to need to be removed and turned off for repair. Similar situations happen 1-2 times during the service life.
Hence the conclusion: overhead taps are placed primarily for servicing the heating system. It is hardly necessary to cut off and dismantle the heat generator.
Above is the standard wiring diagram for a wall-mounted double-circuit boiler, found in each product data sheet. We expanded it, depicting the wiring and potential consumers. Guided by the scheme, carry out the binding, taking into account the recommendations:
- Place taps with a diameter of ½ inch (DN15) on the fittings for gas, cold and hot water.
- Install ¾ ”valves (DN20) on the coolant nozzles. The third tap is designed to empty / feed the system.
- The fittings are screwed down by the Americans.
- Install mud sumps at the inlet from the water supply system and heat network in a horizontal position with the “nose” down, so it’s more convenient to clean them.
- Connect the external expansion tank to the return pipe using additional fittings to cut off and empty the tank, as illustrated in the diagram.
- Place the drain / make-up nozzle with a tap at the lowest point of the system.
Tip. Packing and screwing the valves to the fittings is much more convenient before hanging the boiler on the wall. If “butterflies” or handles interfere with rotation, remove them by unscrewing the nut on the stem. The gas valve is installed through a dielectric gasket.
For homeowners who fill in a non-freezing coolant system and want to play it safe, an alternative double-circuit heater strapping scheme is recommended. Thanks to a pair of taps installed on the supply and return lines, it is possible to dismantle the boiler and maintain the system without draining the antifreeze.
Home connection
The requirements for connecting electricity are quite simple - you need line protection in the form of a circuit breaker and grounding. If there is no powerful equipment in the furnace room, for example, an electric boiler, it is not necessary to run a separate cable to the switchboard. In short, the requirements are as follows:
- Place the switch in a safe place where water or coolant will not get in the event of a breakthrough.
- The presence of a wire connected to the ground loop is required. If the cord in the boiler kit does not have a third core, connect the conductor to the steel body of the heat generator.
- It is not allowed to use metal pipes for heating and water supply as grounding conductors.
- Route the cable in a protective corrugated sleeve.
For reference. European-made turbocharged boilers are sensitive to the correct phase connection. If you mix the neutral and phase wires, the electronic control unit will not start the boiler.
In areas with unstable mains voltage, it is better to power the unit through a stabilizer that protects the electronics from burnout. Frequent interruptions in power supply are an occasion to purchase and install an uninterruptible power supply unit, otherwise, at shutdown, you risk being left without heat.
Mounting the floor unit
Stationary dual-circuit heat generators burning natural gas are divided into 2 varieties - non-volatile and requiring power supply. The second ones are connected to heating and electricity in the same way as the wall "brothers".
The non-volatile floor boiler heats the water in the domestic hot water using a copper or stainless steel coil built into the main heat exchanger. The heater is equipped with a minimum - a burner, safety automatics and a heat exchanger, nothing else. In addition to the cranes listed in the previous section, for installation you will need to buy:
- safety group with a safety valve designed for the operating pressure of the heat generator (indicated in the passport);
- circulation pump;
- expansion tank of the estimated volume (10% of the total amount of coolant).
The circuit for connecting the heating unit to a closed type heating network is shown in the picture.
A few words about how to connect a double-circuit floor boiler to a gravity-free heating system. An open expansion tank with overflow is required here, and a pump and safety group are not needed. Diameters of pipes - not less than 40 mm, laying is carried out with a slope of 5 mm per 1 m running. highways. The heater is the lowest point of the system, and the open tank is placed at the highest. In the presence of electricity, it is possible to organize forced circulation using a pump installed on the bypass.
Double-circuit boiler and indirect heating boiler
This combination began to appear among homeowners who were not satisfied with the operation of the DHW circuit of the gas heat generator. And it is not surprising, because an average power unit is capable of dispensing 10-13 liters of hot water per minute, which is not enough to simultaneously provide two consumers - a sink in the kitchen and a shower.
Another thing is that the purchased indirect heating boiler is connected to the dual-circuit boiler in a perverse way, depicted in the diagram. Simulation of the duct creates an additional circulation pump, which is switched on and stopped by the thermostat signal.
Such a scheme does not work correctly and here's why:
- The heating unit delivers water from the DHW circuit with a maximum temperature of 60 ° C.Passing through the boiler coil, it will never be able to heat its contents (which is 150-200 liters) to the same temperature.
- From the boiler heat exchanger, hot water of 50–55 ° C instead of cold water enters the second circuit of the boiler. It is instantly heated by a burner, which is switched off by a signal from a temperature sensor. But due to the duct, switching on occurs again after a few seconds - there is a “clocking” (start-stop mode), which reduces the life of the heat generator.
- The boiler heats up significantly longer than the set time - from 40 minutes to 2 hours, depending on the power. During this period, the heating is turned off - the unit is occupied by the DHW circuit (see the video above). The house is cooling down.
- A harmful bacterium living in warm water, Legionella, multiplies in the storage tank. It is removed by weekly heating the boiler to a maximum temperature, which is unrealistic to achieve.
In order for the indirect heating boiler to load in 20-25 minutes, connect it in the correct way to the main heating circuit of the gas boiler. Simply shut off the hot water pipes - this will not affect the life of the heat generator. More information on the topic will be given by the expert in his video:
Conclusion
After connecting the double-circuit boiler to heating and power supply, it remains to connect it to the chimney according to the diagram in the operating instructions. More information about installing the chimney of a boiler plant is described in our article on gas columns. The devices, of course, are different, but the requirements for the removal of combustion products are exactly the same.