Wall mounted gas boiler: how to connect the heat

The first thing you need to worry about if you want to gasify your home, is the possibility of gas supply. To do this, you need to contact the local gas supply organization the owner of the pipe . Even if the pipe is just around the corner, the procedure is not that simple, very costly, and the application is only the first part of a long chain of approvals and permits to be passed. But let’s assume that this stage is not difficult, and the necessary pipe is ready to bring to the house connect it only after the installation of all the equipment . And then there is the question of where to install the boiler. For apartments and small private homes, the best place, of course, in the room itself, for larger cottages can be convenient installation in the basement, attic or in the boiler room with a separate entrance. Incorrectly installed boiler is simply not allowed to operate.

Of course, in our country various miracles are possible, but do not count on them: with obvious violations responsible person is unlikely to agree to accept the boiler until they are eliminated, and to redo the system will cost more than to install it correctly at once. For example, the height of the room should be at least 2.5 m for homes, 2.2 m for apartments, a minimum of three times the air exchange per hour, and for boilers with an open chamber to this figure should be added and the volume of air needed for the combustion of gas.

There are requirements for the volume and size of the room, doors and windows, the boiler location and the distance to the walls… the complete list is given in the corresponding regulations: SNiP II-35-76* “Boiler Installations” and SP 41-104-2000 Code of Rules for Design and Construction .

The next task is to install the boiler and connect the necessary utilities. There are no particular technical difficulties in this, in theory, all connections can be made by yourself, especially if you use the appropriate proposed elements. But it is not that simple.

After installation, before putting it into operation, you need several documents: contracts for commissioning and maintenance works, service contracts and an act of demarcation which defines the boundaries of responsibility between the parties that service the mains and the equipment. If the system will be installed gas meter, the number of papers will increase even more.

Almost every commercial organization cooperates with the firms that install gas equipment and have the appropriate licenses for work and certified specialists. But according to some data, the boiler and its installation is ordered by about half of the buyers, the fate of the remaining boilers sellers are unknown, t. e. They are installed either by specialists of gas supplying organization or the owners themselves, or “partisan” hired teams without a license in this case, how to get the necessary documents – the question is not relevant to the topic of this article .

But the nuances of the installation of boilers should be considered in more detail. Whoever sets the boiler – to live in the house will have to, above all, the owner, and the safety should not be forgotten. Yes, and the efficiency and reliability of operation may depend on many things. If you can’t get the power you need because of a “trifle”, that’s half the battle. Worse, if the boiler will fail because of careless installation, and this will probably happen at the most inopportune time – in winter, in the frost.

CAPACITY SELECTION

The boiler itself is only a part of the system, and in order to make a complete calculation, the help of specialists is required. Let’s assume that the place of installation is determined and it complies with all regulations. The next step is to select the output. Approximate criterion – 1 kilowatt per 10 m2 heated area for a well insulated house. It is clear that houses are different, and temperatures vary greatly across the planet and even within the country. Therefore, for an accurate calculation you can order a calculation of heat loss in the house.

And whether there is a sense to save on it is up to the user to decide. In simple cases, for houses up to 200 m2 , it is enough to make a rough estimate based on a few basic data: the area and material of the walls, windows, room height, the minimum design temperature in the region, etc. In Europe, homes of this size account for most of the housing stock, we have larger cottages are more common, but the individual project involves and the corresponding costs. The ideal is to determine the basic elements of the heating system at the design stage, although in fact it does not happen very often.

It should be borne in mind that two-circuit boilers for relatively small areas is more logical to calculate “by DHW”. The data on the boiler output “by water” is in the documentation. For example, for a capacity of 24 kW, it is about 10 l min at a temperature difference of 25-30 ° C, in this mode, the boiler only works to heat water. For a larger capacity you need a boiler. Gas pressure in our networks can also vary from the calculated pressure downwards, especially in winter, when there is a consumption peak, and as a result the real heat output of the boiler will decrease. If in large houses, for example, you can reduce the heat supply to unused rooms, in smaller areas such areas may simply not be.

GAS

If there is a gas pipe nearby, it seems to be the easiest connection except for the fact that it will be the main focus of acceptance . The most reliable way – a metal pipe. There will be no questions to it, except that you need to paint. In practice, however, this is a relatively time-consuming process, which is especially popular when connecting stationary floor boilers, and for the much more commonly used wall-mounted are widely used flexible rubber hoses in the braid.

This is acceptable, but it should be remembered that the rubber dries out over time and becomes covered with cracks, through which the leakage will begin. The service life of such hoses is determined by the manufacturer and is on average five years, then the hose needs to be replaced. Another option – a flexible bellows line steel corrugated hose is easy to install and does not deteriorate over time .

Often encountered mistake at this stage – unsuitable gaskets in the joints. For sealing the joints of gas pipelines use paronite gaskets. Elastic rubber , of course, is good to prevent possible leaks, but can squeeze and narrow the cross-section for the passage of gas, as a result of the boiler can not work at full capacity.

All connections must be tightened firmly, reliably, but not to the state “a little more – and the thread will curdle”. Excessive voltages in the connections are unacceptable, however, this applies not only to gas, but also to the pipes of heating and hot water systems. The boiler will not start if the gas pressure in the system will be higher or lower than acceptable, but this depends on its adjustment by a specialist and the pressure in the pipeline.

ELECTRICITY

Recommendations here are simple: regardless of whether the boiler comes with a cable and plug or you have to connect it to a panelboard, you must take care of a reliable grounding. It is recommended to remember about the dielectric insert between the gas pipe and the boiler, so that the current does not “come” from the neighbors. In rural areas, where a three-wire scheme is not found everywhere, the “ground” will have to do separately. Of course, you can not be grounded on the gas or heating pipe.

According to electrical safety standards, the boiler must be connected to the electricity supply only through the automatic switch-off device automatic , which is also located near the boiler to be able to quickly turn off the power. For this reason, you must not plug the boiler into a normal socket. It is also not allowed to pull the cable to the junction box without an automatic circuit breaker. Both methods do not allow for emergency power outage of the boiler in the event of an emergency.

In order not to destroy electronic components, it is desirable to use voltage regulators and separate circuit breakers. Of course, in case of power outage the boiler can not work, but with a proper calculation and thermal insulation takes into account the possible break a few hours a day , in which the residual heat in the heating system will be enough to maintain a comfortable temperature.

Also possible and autonomous operation of the boiler with power from backup power sources when turning off the main, especially since the entire system does not need much electricity from 80 to 180 watts . Such schemes are used, though seldom.

AIR SUPPLY AND FLUE GAS EVACUATION

For atmospheric models, a ventilation system and a single chimney, which can be taken out through the roof or through the wall, of course, in compliance with fire safety rules. For the combustion of gas there must be an inflow of air from the outside into the room, which means additional energy costs for heating in winter. This additional heat consumption must be taken into account when calculating the necessary boiler output.

For boilers with a closed chamber, you must provide an air supply from outside, through a separate pipe from the chimney or coaxial: combustion products are exhausted through the inner pipe, and in the space between the inner and outer air is supplied. This means that boilers with a closed chamber can be of lower capacity than open chamber.

A significant number of errors in the installation of gas supply systems is associated with chimneys. Producers offer many varieties of pipes and adapters, and to pick up the complete set is usually not difficult. The desire to save money in this case is not always justified. The proposed pipes are adapted to the conditions of the gas boiler, and do not know that the other, “cheaper” will serve as well. Resistance to burnout and condensation inside metal pipes is important for metal pipes, while heat resistance and reliability of seals in the joints is important for plastic ones.

There are requirements for the location of pipes, and even for the slope of their horizontal sections, if any. For example, if the output into the wall is used, on standard boilers the horizontal pipes must have a slight slope towards the street, and on the contrary, on condensing boilers the output pipe must have a slope towards the boiler so that the condensate can flow back. It is strictly forbidden to overdo the chimney. Chimney installation options are available in the documentation of the equipment.

Note that the maximum length of the coaxial pipe is 3-5 meters, and each turn and bend reduces this size. It is most often led through the wall to the outside. For “single” pipe lengths can be counted in tens of meters. Do not lead the end of the pipe into an existing brickwork vertical duct e.g. a chimney flue : condensation is very aggressive, it must be continued all the way to the top.

Condensing boilers have one more “connection point” – a siphon for the condensate drain. Chemically it is quite aggressive liquid, it is wrong to drain outdoors through the tube: and the soil in this place will turn sour, and the tube in winter can freeze, resulting in stopping the boiler. Drainage of condensate must be carried out in the drain.

Set Giacomini R568B2 is designed to arrange two independent radiator heating circuits, for example for heating residential and auxiliary rooms. It consists of the R554 safety group with safety and air valves, pressure gauge and fill-drain cock, two R586 brass boiler manifolds, R295 4-way mixing valves, circulation pumps and two R284M pressure and control groups ball valves with thermometers in the forward and return lines, differential and non return valves .

The kit can be mounted on the wall using special brackets. Other configuration types are also possible, for example if one of the 4-way valves is replaced by a 3-way valve, low-temperature heating systems can be connected to the circuit such kit is called R568F .

Under this name are usually offered fully assembled components of boiler piping installed in a thermally insulating shell and mounted on a distribution manifold or on the wall. Convenience modules – easy installation, and about the aesthetic component is not worth forgetting: instead of a set of details the user sees a casing with windows for thermometers and outlets for connecting pipes.

The model is designed to limit the temperature of the heat transfer fluid in the heating system and can be used for both radiator heating and floor heating. Maximum working temperature – 110 °C. The piping system comprises a shut-off valve unit with thermometers in the front and back circuits, incorporated in the ball valve knobs, a non-return valve, a circulation pump, a ball valve before the pump, and a three-way mixer with an electric motor.

The module is delivered assembled, the threaded connections are “tightened”, but not tightened, so you can, if necessary, make changes to the hydraulic scheme of the module possibly swap the supply and return lines . Distance between straight and return line – 125 mm. Insulating shell is made of foamed polyethylene “rubber foam plastic” .

HEATING AND HOT WATER CIRCUITS

Next, the boiler must be connected to the circuits for which it was purchased, i.e. e. to heating and possibly hot water systems. Small wall-mounted variants are usually complete ready to connect unit burner, boiler, piping and electronics in one case , in more powerful wall and floor variants are possible: some equipment you may have to buy separately, choosing the most suitable elements for your needs.

This is not surprising, in general such boilers provide more opportunities for the design of heating systems. Combined systems are also possible, in which several different sources are used to produce hot water under common control, for example, part of the energy comes from solar collectors. However, we will not talk about heating systems, we will confine ourselves to those elements that most often go “up to the pipes”.

And the first thing you should take care of is the taps on all pipes, so that in case of repair to close them and disconnect the boiler from the system without draining liquids. On the supply pipe of the DHW system and “return” of the heating system before the circulation pump, which is also placed in the “return”, before the heat exchanger filters must be installed. If the hardness of water supplied for DHW saturation of salts, especially calcium and magnesium is high, it makes sense to soften it beforehand, otherwise these salts will very quickly deposit on the heat exchanger tubes. Several varieties of devices are used in the home: with a metered flow of chemical, a system for magnetic or ion-exchange treatment.

Schemes of heating a lot, to list even the main options is difficult, so we will limit ourselves to the basic theses. There is a high-temperature “warm floor” and low-temperature “underfloor heating” heating. The first is easier to implement, the second is more compact, cost-effective, but requires complex work. Most of the boilers supplied to us are designed to work in high-temperature heating conditions, some can be converted to low-temperature mode.

If the “hot” boiler is set for low-temperature heating, you can use a three-way valve, which mixes hot water from the boiler with chilled water from the return line. Simultaneous realization of both options from a single boiler is also possible, then the valve is placed only on the low-temperature circuit of the system, and the radiator heating is fed by hot water. When calculating the branched and complex heating system it is also necessary to calculate the volume of the expansion tank. If it is included in the set, its volume is most likely sufficient, but it does not hurt to check it once again.

If the boiler is single-circuit, and you want to also prepare hot water, you can not do without the boiler. For two-circuit boiler is possible, but not obligatory. Here you must at least roughly imagine the maximum simultaneous demand for hot water from the residents.

It is advisable to insulate heating pipes. The simplest way is to put special foam tubes on them.

As the heating liquid is used either water or antifreeze. These fluids are almost never wasted under normal conditions, but the issue of quality is also important. Water, of course, must not contain salts and other impurities: all of them will eventually settle on the internal elements of the heating system and reduce the heat output. Seems like a trifle, but you have to pay for it from your pocket.

This is especially important when periodically using the boiler with its preservation draining coolant and moving residents for the winter in the city: it is clear that each new season the water will be renewed, and the amount of scaling – to increase. Even more interesting situation with antifreeze. Compared with water it has only one major advantage – it does not freeze in winter.

But there are also disadvantages: lower heat capacity, higher coefficient of thermal expansion and viscosity. In practice this means that you need a larger battery area, pumps with increased capacity, a larger storage tank and, most importantly, a boiler of greater capacity.

Is there a sense to increase the cost of the entire system, especially in the case of relatively inexpensive wall boilers – a question that has no unambiguous answer: during normal operation of any boiler freezing of the coolant is impossible: there is an automatic mode of its heating in the “standby” mode. In general, when designing the system, it is necessary to decide in advance on the type of coolant.

antifreezes have different compositions, and not all are suitable for heating some brands start to decompose already at 70 ° C . The only advice here is to follow the manufacturer’s recommendations. Many companies offer antifreeze under their own brand names and guarantee its compatibility with the system. No one conducts or intends to conduct tests of other brands of antifreeze with their own antifreeze, for obvious reasons. Of course, you can not mix different brands of antifreeze, and every few years you need a complete change of heating fluid.

It should be remembered that the use of antifreeze is advisable either for safety precautions, or for periodic residence, with departures for long periods and disconnections of the boiler from the network. In normal operation the boiler protects itself from freezing: at a water temperature of about 5 ° C, it briefly turns on and heats the liquid but not the room .

Circulation pump and three-way valve protection function is to “turn” them periodically once a day by the boiler automatics system even during operation in the “summer” mode. If the boiler has been preserved, before turning it on it makes sense to check them, and in general all similar elements of the heating system, including taps, manually. It is not difficult, to turn the pump shaft, you need to remove the plug on its body and twist the shaft with a screwdriver.

SENSORS AND OTHER DEVICES

Control of all systems of modern boilers is automatic. Electronics through sensors to monitor the temperature in the circuits, flow, pressure, and other parameters. This is done not only for the sake of convenience, but also for fuel economy. Even a simple control unit usually has at least the possibility of connecting a remote control and an outdoor temperature sensor, which can significantly reduce heating costs.

In more complex models, you can connect or program different modes of operation, such as a slight decrease in temperature and consumption at night, weekly mode, when the boiler mostly maintains a low temperature in the house and comes out at full power to the arrival of the owners, and much more.

List all the features of control systems is difficult: for “advanced” boilers, often instead of simple electronics are offered a more sophisticated control unit capable of working not only with the boiler, but also other elements of heating and DHW. Very popular option with the management of the boiler via GSM-channel: call – and a few hours later the house is ready for the arrival of guests.

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