Flame propagation processes, incomplete combustion. Natural gas
Gas combustion is a combination of the following processes:
Mixing combustible gas with air
heating the mixture
thermal decomposition of combustible components,
Ignition and chemical combination of combustible components with atmospheric oxygen, accompanied by the formation of a torch and intense heat release.
The combustion of methane occurs according to the reaction:
CH 4 + 2O 2 \u003d CO 2 + 2H 2 O
Conditions required for gas combustion:
Ensuring the required ratio of combustible gas and air,
heating up to ignition temperature.
If the gas-air mixture of gas is less than the lower flammable limit, then it will not burn.
If there is more gas in the gas-air mixture than the upper flammable limit, then it will not burn completely.
The composition of the products of complete combustion of gas:
CO 2 - carbon dioxide
H 2 O - water vapor
* N 2 - nitrogen (it does not react with oxygen during combustion)
Composition of products of incomplete combustion of gas:
CO - carbon monoxide
C - soot.
Combustion of 1 m 3 of natural gas requires 9.5 m 3 of air. In practice, air consumption is always higher.
Attitude actual consumption air to theoretically required flow is called the excess air coefficient: α = L/L t .,
Where: L- actual expense;
L t - theoretically required flow.
The excess air coefficient is always greater than one. For natural gas, it is 1.05 - 1.2.
2. Purpose, device and main characteristics of instantaneous water heaters.
Flowing gas water heaters. Designed to heat water to a certain temperature during drawdown. Flowing water heaters are divided according to the load of thermal power: 33600, 75600, 105000 kJ, according to the degree of automation - into the highest and first classes. efficiency water heaters 80%, oxide content is not more than 0.05%, the temperature of the combustion products behind the draft interrupter is not less than 180 0 C. The principle is based on heating water during the drawdown period.
The main units of instantaneous water heaters are: a gas burner, a heat exchanger, an automation system and a gas outlet. Gas low pressure fed into the injection burner. The combustion products pass through the heat exchanger and are discharged into the chimney. The heat of combustion is transferred to the water flowing through the heat exchanger. To cool the fire chamber, a coil is used, through which water circulates, passing through the heater. Gas instantaneous water heaters are equipped with gas exhaust devices and draft breakers, which, in the event of a short-term violation of draft, prevent the flame of the gas burner from extinguishing. There is a flue pipe for connection to the chimney.
Gas instantaneous water heater– HSV. On the front wall of the casing there are: a gas cock control knob, a button for turning on the solenoid valve and a viewing window for observing the flame of the pilot and main burners. At the top of the device there is a smoke exhaust device, at the bottom there are branch pipes for connecting the device to the gas and water systems. The gas enters the solenoid valve, the gas shut-off valve of the water and gas burner block sequentially turns on the pilot burner and supplies gas to the main burner.
Blocking the flow of gas to the main burner, when compulsory work igniter, carries out a solenoid valve operating from a thermocouple. Blocking the gas supply to the main burner, depending on the presence of water intake, is carried out by a valve driven through the stem from the membrane of the water block valve.
Anthropotoxins;
Destruction products of polymeric materials;
Substances entering the room with polluted atmospheric air;
Chemical substances released from polymeric materials, even in small quantities, can cause significant disturbances in the state of a living organism, for example, in the case of allergic exposure to polymeric materials.
The intensity of the release of volatile substances depends on the operating conditions of polymeric materials - temperature, humidity, air exchange rate, operating time.
A direct dependence of the level of chemical pollution of the air on the total saturation of the premises has been established. polymeric materials.
A growing organism is more sensitive to the effects of volatile components from polymeric materials. An increased sensitivity of patients to the effects of chemical substances released from plastics compared to healthy ones. Studies have shown that in rooms with a high saturation of polymers, the susceptibility of the population to allergic, colds, neurasthenia, vegetative dystonia, and hypertension was higher than in rooms where polymer materials were used in smaller quantities.
To ensure the safety of the use of polymeric materials, it is accepted that the concentrations of volatile substances released from polymers in residential and public buildings should not exceed their MPC established for atmospheric air, and the total ratio of the detected concentrations of several substances to their MPC should not exceed one. For the purpose of preventive sanitary supervision for polymeric materials and products made from them, it was proposed to limit the release of harmful substances in environment or at the stage of manufacture, or shortly after their release by manufacturers. Permissible levels of about 100 chemicals released from polymeric materials have now been substantiated.
AT modern construction there is a growing trend towards chemization technological processes and use as mixtures of various substances, primarily concrete and reinforced concrete. From a hygienic point of view, it is important to take into account the adverse effects of chemical additives in building materials due to the release of toxic substances.
No less powerful internal source of pollution of the indoor environment are human waste products anthropotoxins. It has been established that in the process of life a person releases approximately 400 chemical compounds.
Studies have shown that the air environment of unventilated rooms deteriorates in proportion to the number of people and the time they spend in the room. Chemical analysis of indoor air made it possible to identify a number of toxic substances in them, the distribution of which according to hazard classes is as follows: dimethylamine, hydrogen sulfide, nitrogen dioxide, ethylene oxide, benzene (the second hazard class is highly hazardous substances); acetic acid, phenol, methylstyrene, toluene, methanol, vinyl acetate (the third hazard class is low-hazard substances). One fifth of the identified anthropotoxins are classified as highly hazardous substances. At the same time, it was found that in an unventilated room, the concentrations of dimethylamine and hydrogen sulfide exceeded the MPC for atmospheric air. The concentrations of substances such as carbon dioxide, carbon monoxide, and ammonia also exceeded the MPC or were at their level. The remaining substances, although they amounted to tenths and smaller fractions of the MPC, taken together testified to the unfavorable air environment, since even a two-four-hour stay in these conditions had a negative effect on the mental performance of the subjects.
The study of the air environment of gasified premises showed that during the hourly combustion of gas in the indoor air, the concentration of substances was (mg / m 3): carbon monoxide - an average of 15, formaldehyde - 0.037, nitrogen oxide - 0.62, nitrogen dioxide - 0.44, benzene - 0.07. The air temperature in the room during the combustion of gas increased by 3-6 ° C, the humidity increased by 10-15%. Moreover, high concentrations of chemical compounds were observed not only in the kitchen, but also in the living quarters of the apartment. After turning off the gas appliances, the content of carbon monoxide and other chemicals in the air decreased, but sometimes did not return to the original values even after 1.5-2.5 hours.
The study of the effect of household gas combustion products on human external respiration revealed an increase in the load on the respiratory system and a change in the functional state of the central nervous system.
One of the most common sources of indoor air pollution is smoking. Spectrometric analysis of air polluted with tobacco smoke revealed 186 chemical compounds. In insufficiently ventilated rooms, air pollution by smoking products can reach 60-90%.
When studying the effects of components tobacco smoke on non-smokers (passive smoking), the subjects experienced irritation of the mucous membranes of the eyes, an increase in the content of carboxyhemoglobin in the blood, an increase in heart rate, an increase in the level blood pressure. Thus, main sources of pollution The air environment of the premises can be conditionally divided into four groups:
The significance of internal sources of pollution in different types of buildings is not the same. AT administrative buildings the level of total pollution most closely correlates with the saturation of the premises with polymeric materials (R = 0.75), in indoor sports facilities the level of chemical pollution correlates most well with the number of people in them (R = 0.75). For residential buildings the closeness of the correlation between the level of chemical pollution both with the saturation of the premises with polymeric materials and with the number of people in the premises is approximately the same.
Chemical pollution of the air environment of residential and public buildings under certain conditions (poor ventilation, excessive saturation of the premises with polymeric materials, large crowds of people, etc.) can reach a level that Negative influence on the general condition of the human body.
AT last years According to WHO, the number of reports of the so-called sick building syndrome has increased significantly. The described symptoms of deterioration in the health of people living or working in such buildings are very diverse, but they also have a number common features, namely: headaches, mental fatigue, increased frequency of airborne infections and colds, irritation of the mucous membranes of the eyes, nose, throat, feeling of dryness of the mucous membranes and skin, nausea, dizziness.
The first category - temporarily "sick" buildings- includes newly built or recently renovated buildings in which the intensity of the manifestation of these symptoms weakens over time and in most cases they disappear completely after about six months. The decrease in the severity of symptoms may be associated with the patterns of emission of volatile components contained in building materials, paints, etc.
In buildings of the second category - constantly "sick" the described symptoms are observed for many years, and even large-scale recreational activities may not have an effect. As a rule, it is difficult to find an explanation for this situation, despite a thorough study of the composition of air, work ventilation system and building design features.
It should be noted that it is not always possible to detect a direct relationship between the state of the indoor air environment and the state of public health.
However, providing an optimal air environment for residential and public buildings is an important hygienic and engineering problem. The leading link in solving this problem is the air exchange of the premises, which provides the required parameters of the air environment. When designing air conditioning systems in residential and public buildings, the required air supply rate is calculated in an amount sufficient to assimilate human heat and moisture emissions, exhaled carbon dioxide, and in rooms intended for smoking, the need to remove tobacco smoke is also taken into account.
In addition to regulating the amount of supply air and its chemical composition known value to ensure air comfort indoors, it has an electrical characteristic of the air environment. The latter is determined by the ionic regime of the premises, i.e. the level of positive and negative air ionization. Negative impact both insufficient and excessive air ionization has an effect on the body.
Living in areas with a content of negative air ions of the order of 1000-2000 in 1 ml of air has a positive effect on the health of the population.
The presence of people in the premises causes a decrease in the content of light air ions. At the same time, the ionization of air changes more intensively, the more people in the room and the smaller its area.
A decrease in the number of light ions is associated with the loss of air refreshing properties, with its lower physiological and chemical activity, which adversely affects the human body and causes complaints of stuffiness and "lack of oxygen". Therefore, of particular interest are the processes of deionization and artificial ionization of indoor air, which, of course, must have hygienic regulation.
It should be emphasized that artificial ionization of indoor air without sufficient air supply under conditions high humidity and dustiness of the air leads to an inevitable increase in the number of heavy ions. In addition, in the case of ionization of dusty air, the percentage of dust retention in the respiratory tract increases sharply (dust carrying electrical charges lingers in the respiratory tract of a person for much more than neutral).
Consequently, artificial air ionization is not a universal panacea for improving indoor air. Without improving all the hygienic parameters of the air environment, artificial ionization not only does not improve human living conditions, but, on the contrary, can have a negative effect.
The optimal total concentrations of light ions are levels of the order of 3 x 10, and the minimum required is 5 x 10 in 1 cm 3. These recommendations formed the basis of the current Russian Federation sanitary and hygienic standards of permissible levels of air ionization in industrial and public premises (Table 6.1).
General information. Another important source of internal pollution, a strong sensitizing factor for humans, is natural gas and its combustion products. Gas is a multicomponent system consisting of dozens of different compounds, including specially added ones (Table 1).
Available direct evidence the fact that the use of appliances that burn natural gas (gas stoves and boilers) has an adverse effect on human health. In addition, individuals with increased sensitivity to environmental factors react inadequately to natural gas components and products of its combustion.
Natural gas in the home - a source of many different pollutants. These include compounds that are directly present in the gas (odorants, gaseous hydrocarbons, toxic organometallic complexes and radioactive gas radon), products of incomplete combustion (carbon monoxide, nitrogen dioxide, aerosol organic particles, polycyclic aromatic hydrocarbons and small amounts of volatile organic compounds). All of these components can affect the human body both by themselves and in combination with each other (synergistic effect).
Table 12.3
Composition of gaseous fuel
Odorants. Odorants are sulfur-containing organic aromatic compounds (mercaptans, thioethers and thio-aromatic compounds). They are added to natural gas in order to detect it in case of leaks. Although these compounds are present in very low, sub-threshold concentrations that are not considered toxic to most individuals, their odor can cause nausea and headaches in otherwise healthy individuals.
Clinical experience and epidemiological data indicate that chemically sensitive individuals react inappropriately to chemicals present even at subthreshold concentrations. Individuals with asthma often identify odor as a promoter (trigger) of asthmatic attacks.
Odorants include, for example, methanethiol. Methanethiol, also known as methylmercaptan (mercaptomethane, thiomethylalcohol), is a gaseous compound commonly used as an aromatic additive to natural gas. Bad smell is felt by most people at a concentration of 1 part per 140 ppm, however, this compound can be detected at much lower concentrations by highly sensitive individuals. Toxicological studies in animals have shown that 0.16% methanethiol, 3.3% ethanethiol, or 9.6% dimethyl sulfide can induce comatose states in 50% of rats exposed to these compounds for 15 minutes.
Another mercaptan, also used as an aromatic additive to natural gas, is mercaptoethanol (C2H6OS) also known as 2-thioethanol, ethyl mercaptan. Severe irritant to eyes and skin, capable of exerting a toxic effect through the skin. It is flammable and decomposes when heated to form highly toxic SOx fumes.
Mercaptans, being indoor air pollutants, contain sulfur and can capture elemental mercury. In high concentrations, mercaptans can cause impaired peripheral circulation and increased heart rate, can stimulate loss of consciousness, the development of cyanosis, or even death.
Aerosols. Combustion of natural gas results in the formation of fine organic particles (aerosols), including carcinogenic aromatic hydrocarbons, as well as some volatile organic compounds. DOS are suspected sensitizing agents that are able to induce, together with other components, the "sick building" syndrome, as well as multiple chemical sensitivity (MCS).
DOS also includes formaldehyde, which is formed in small quantities during the combustion of gas. The use of gas appliances in a home where sensitive individuals live increases exposure to these irritants, subsequently exacerbating the signs of illness and also promoting further sensitization.
Aerosols formed during the combustion of natural gas can become adsorption centers for a variety of chemical compounds present in the air. Thus, air pollutants can be concentrated in microvolumes, react with each other, especially when metals act as catalysts for reactions. The smaller the particle, the higher the concentration activity of such a process.
Moreover, water vapor generated during the combustion of natural gas is a transport link for aerosol particles and pollutants when they are transferred to the pulmonary alveoli.
During the combustion of natural gas, aerosols containing polycyclic aromatic hydrocarbons are also formed. They have adverse effects on the respiratory system and are known carcinogens. In addition, hydrocarbons can lead to chronic intoxication in susceptible people.
The formation of benzene, toluene, ethylbenzene and xylene when burning natural gas is also unfavorable to human health. Benzene is known to be carcinogenic at doses well below the threshold. Exposure to benzene has been correlated with an increased risk of cancer, especially leukemia. The sensitizing effects of benzene are not known.
organometallic compounds. Some natural gas components may contain high concentrations of toxic heavy metals, including lead, copper, mercury, silver, and arsenic. In all likelihood, these metals are present in natural gas in the form of organometallic complexes of the trimethylarsenite (CH3)3As type. The association with the organic matrix of these toxic metals makes them lipid soluble. This leads to a high level of absorption and a tendency to bioaccumulate in human adipose tissue. The high toxicity of tetramethylplumbite (CH3)4Pb and dimethylmercury (CH3)2Hg suggests an impact on human health, as the methylated compounds of these metals are more toxic than the metals themselves. Of particular danger are these compounds during lactation in women, since in this case there is a migration of lipids from the fat depots of the body.
Dimethylmercury (CH3)2Hg is a particularly dangerous organometallic compound due to its high lipophilicity. Methylmercury can be incorporated into the body through inhalation as well as through the skin. The absorption of this compound in the gastrointestinal tract is almost 100%. Mercury has a pronounced neurotoxic effect and the ability to influence the human reproductive function. Toxicology does not have data on safe levels of mercury for living organisms.
Organic arsenic compounds are also very toxic, especially when they are metabolically destroyed (metabolic activation), resulting in the formation of highly toxic inorganic forms.
Combustion products of natural gas. Nitrogen dioxide is able to act on the pulmonary system, which facilitates the development of allergic reactions to other substances, reduces lung function, susceptibility to infectious diseases lungs, potentiates bronchial asthma and other respiratory diseases. This is especially pronounced in children.
There is evidence that N02 produced by burning natural gas can induce:
- inflammation of the pulmonary system and a decrease in the vital function of the lungs;
- increased risk of asthma-like symptoms, including wheezing, shortness of breath and asthma attacks. This is especially common in women cooking on gas stoves, as well as in children;
- a decrease in resistance to bacterial lung diseases due to a decrease in the immunological mechanisms of lung protection;
- overall adverse effects on immune system human and animals;
- impact as an adjuvant on the development of allergic reactions to other components;
- increased sensitivity and increased allergic response to side allergens.
Natural gas combustion products contain a rather high concentration of hydrogen sulfide (H2S), which pollutes the environment. It is poisonous at concentrations lower than 50.ppm, and at concentrations of 0.1-0.2% it is fatal even with short exposure. Since the body has a mechanism to detoxify this compound, the toxicity of hydrogen sulfide is related more to the exposure concentration than to the duration of exposure.
Although hydrogen sulfide has a strong odor, continuous exposure to low concentrations leads to a loss of the sense of smell. This makes a toxic effect possible for people who may unknowingly be exposed to dangerous levels of this gas. Insignificant concentrations of it in the air of residential premises lead to irritation of the eyes, nasopharynx. Moderate levels cause headache, dizziness, as well as coughing and difficulty breathing. high levels lead to shock, convulsions, coma, which end in death. Survivors of acute toxic exposure to hydrogen sulfide experience neurological dysfunctions such as amnesia, tremors, imbalance, and sometimes more severe brain damage.
The acute toxicity at relatively high concentrations of hydrogen sulfide is well known, however, unfortunately, little information is available on the chronic low-dose effects of this component.
Radon. Radon (222Rn) is also present in natural gas and can be transported through pipelines to gas stoves, which become sources of pollution. Since radon decays to lead (the half-life of 210Pb is 3.8 days), this results in a thin layer of radioactive lead (on average 0.01 cm thick) that covers internal surfaces pipes and equipment. The formation of a layer of radioactive lead increases the background value of radioactivity by several thousand disintegrations per minute (over an area of 100 cm2). Removing it is very difficult and requires the replacement of pipes.
It should be borne in mind that simply turning off the gas equipment is not enough to remove the toxic effects and bring relief to chemically sensitive patients. Gas equipment must be completely removed from the premises, since even a non-working gas stove continues to release aromatic compounds that it has absorbed over the years of use.
The cumulative effects of natural gas, aromatic compounds, and combustion products on human health are not exactly known. It is assumed that the effects from several compounds may be multiplied, while the response from exposure to several pollutants may be greater than the sum of the individual effects.
Thus, the characteristics of natural gas that are of concern to human and animal health are:
- flammability and explosive character;
- asphyxic properties;
- pollution by products of combustion of the indoor air;
- the presence of radioactive elements (radon);
- the content of highly toxic compounds in the combustion products;
- the presence of trace amounts of toxic metals;
- the content of toxic aromatic compounds added to natural gas (especially for people with multiple chemical sensitivities);
- the ability of gas components to sensitize.
Natural gas is the most widely used fuel today. Natural gas is called natural gas because it is extracted from the very bowels of the Earth.
The process of gas combustion is a chemical reaction in which natural gas interacts with oxygen contained in the air.
In gaseous fuel there is a combustible part and a non-combustible part.
The main combustible component of natural gas is methane - CH4. Its content in natural gas reaches 98%. Methane is odorless, tasteless and non-toxic. Its flammability limit is from 5 to 15%. It is these qualities that made it possible to use natural gas as one of the main types of fuel. The concentration of methane is more than 10% dangerous for life, so suffocation can occur due to lack of oxygen.
To detect a gas leak, the gas is subjected to odorization, in other words, a strong-smelling substance (ethyl mercaptan) is added. In this case, the gas can be detected already at a concentration of 1%.
In addition to methane, combustible gases such as propane, butane and ethane may be present in natural gas.
To ensure high-quality gas combustion, it is necessary to bring air into the combustion zone in sufficient quantities and achieve good mixing of gas with air. The ratio of 1: 10 is considered optimal. That is, ten parts of air fall on one part of the gas. In addition, it is necessary to create the necessary temperature regime. In order for the gas to ignite, it must be heated to its ignition temperature and in the future the temperature should not fall below the ignition temperature.
It is necessary to organize the removal of combustion products into the atmosphere.
Complete combustion is achieved if there are no combustible substances in the combustion products released into the atmosphere. In this case, carbon and hydrogen combine together and form carbon dioxide and water vapor.
Visually, with complete combustion, the flame is light blue or bluish-violet.
In addition to these gases, nitrogen and the remaining oxygen enter the atmosphere with combustible gases. N 2 + O 2
If the combustion of gas is not complete, then combustible substances are emitted into the atmosphere - carbon monoxide, hydrogen, soot.
Incomplete combustion of gas occurs due to insufficient air. At the same time, tongues of soot appear visually in the flame.
The danger of incomplete combustion of gas is that carbon monoxide can cause poisoning of boiler room personnel. The content of CO in the air 0.01-0.02% can cause mild poisoning. Higher concentrations can lead to severe poisoning and death.
The resulting soot settles on the walls of the boilers, thereby worsening the transfer of heat to the coolant, which reduces the efficiency of the boiler house. Soot conducts heat 200 times worse than methane.
Theoretically, 9m3 of air is needed to burn 1m3 of gas. In real conditions, more air is needed.
That is, an excess amount of air is needed. This value, denoted alpha, shows how many times more air is consumed than theoretically necessary.
The alpha coefficient depends on the type of a particular burner and is usually prescribed in the burner passport or in accordance with the recommendations of the commissioning organization.
With an increase in the number excess air higher than recommended, heat losses increase. With a significant increase in the amount of air, flame separation can occur, creating an emergency. If the amount of air is less than recommended, then combustion will be incomplete, thereby creating a risk of poisoning the boiler room personnel.
For more accurate control of the quality of fuel combustion, there are devices - gas analyzers that measure the content of certain substances in the composition of exhaust gases.
Gas analyzers can be supplied with boilers. If they are not available, the relevant measurements are carried out by the commissioning organization using portable gas analyzers. A regime map is compiled in which the necessary control parameters are prescribed. By adhering to them, you can ensure the normal complete combustion of the fuel.
The main parameters for fuel combustion control are:
- the ratio of gas and air supplied to the burners.
- excess air ratio.
- crack in the furnace.
- Boiler efficiency factor.
At the same time, the efficiency of the boiler means the ratio of useful heat to the value of the total heat expended.
Composition of air
| Gas name | Chemical element | Content in the air |
| Nitrogen | N2 | 78 % |
| Oxygen | O2 | 21 % |
| Argon | Ar | 1 % |
| Carbon dioxide | CO2 | 0.03 % |
| Helium | He | less than 0.001% |
| Hydrogen | H2 | less than 0.001% |
| Neon | Ne | less than 0.001% |
| Methane | CH4 | less than 0.001% |
| Krypton | kr | less than 0.001% |
| Xenon | Xe | less than 0.001% |
The location of the elements of the automation device is shown in fig. 7. It shows that the electromagnet is closed with a protective cap. The wires from the sensors are located inside thin-walled tubes. The tubes are attached to the electromagnet using cap nuts. The body leads of the sensors are connected to the electromagnet through the body of the tubes themselves.
And now consider the method of finding the above fault.
The check begins with the “weakest link” of the automation device - the thrust sensor. The sensor is not protected by a casing, therefore, after 6 ... 12 months of operation, it “overgrows” with a thick layer of dust. The bimetallic plate (see Fig. 6) quickly oxidizes, which leads to poor contact.
The dust coat is removed with a soft brush. Then the plate is pulled away from contact and cleaned with fine sandpaper. We should not forget that it is necessary to clean the contact itself. Good results are obtained by cleaning these elements with a special spray "Contact". It contains substances that actively destroy the oxide film. After cleaning, the plate and contact are applied thin layer liquid lubricant.
The next step is to check the health of the thermocouple. It works in heavy thermal conditions, as it is constantly in the igniter flame, naturally, its service life is much less than the rest of the boiler elements.
The main defect of the thermocouple is burnout (destruction) of its body. At the same time, there is a sharp increase contact resistance at the place of welding (junction). As a result, the current in the circuit Thermocouple - Electromagnet
- The bimetal plate will be lower than the nominal value, which leads to the fact that the electromagnet will no longer be able to fix the stem (Fig. 5).
To check the thermocouple, unscrew the union nut (Fig. 7), located on the left 
side of the electromagnet. Then the igniter is turned on and the constant voltage (thermo-EMF) at the thermocouple contacts is measured with a voltmeter (Fig. 8). A heated serviceable thermocouple generates an EMF of about 25 ... 30 mV. If this value is less, the thermocouple is faulty. For its final check, the tube is undocked from the casing of the electromagnet and the resistance of the thermocouple is measured. The resistance of the heated thermocouple is less than 1 ohm. If the resistance of the thermocouple is hundreds of ohms or more, it must be replaced. The low value of thermo-EMF generated by a thermocouple can be caused by the following reasons: - clogging of the igniter nozzle (as a result, the heating temperature of the thermocouple may be lower than the nominal one). A similar defect is “treated” by cleaning the igniter hole with any soft wire of a suitable diameter;
- by shifting the position of the thermocouple (naturally, it can also not heat up enough). Eliminate the defect as follows - loosen the screw for fastening the eyeliner near the igniter and adjust the position of the thermocouple (Fig. 10);
- low gas pressure at the boiler inlet.
If the EMF at the thermocouple leads is normal (while maintaining the symptoms of the malfunction indicated above), then the following elements are checked:
- the integrity of the contacts at the connection points of the thermocouple and the draft sensor.
Oxidized contacts must be cleaned. union nuts twist, as they say, "by hand". In this case, it is undesirable to use a wrench, since it is easy to break the wires suitable for the contacts;
- the integrity of the electromagnet winding and, if necessary, solder its conclusions.
The performance of the electromagnet can be checked as follows. Disconnect 
thermocouple lead. Press and hold the start button, then ignite the igniter. From a separate source of constant voltage to the released contact of the electromagnet (from the thermocouple), a voltage of about 1 V is applied relative to the housing (at a current of up to 2 A). To do this, you can use a regular battery (1.5 V), as long as it provides the necessary operating current. Now the button can be released. If the igniter does not go out, the electromagnet and draft sensor are working;
- thrust sensor. First, the force of pressing the contact to the bimetallic plate is checked (with the indicated signs of a malfunction, it is often insufficient). To increase the clamping force, loosen the lock nut and move the contact closer to the plate, then tighten the nut. In this case, no additional adjustments not required - the clamping force does not affect the temperature of the sensor response. The sensor has a large margin for the angle of deflection of the plate, ensuring reliable breaking of the electrical circuit in the event of an accident.
We also recommend
Productive and reproductive thinking
Reasonable egoism - what is the theory of reasonable egoism?
Boris Nikolaevich Yeltsin, the first President of Russia
Underground fights. Underground kings. What is “fighting not for the masses”? Where can you fight for money?
Yakov Pavlov and Other Heroes of Stalingrad You Need to Know
Survive an accident at sea in a dream - in reality experience a new love
Loading...