Gasification has been progressing at a fairly rapid pace lately. settlements Russia. The main element of equipment that is installed in each rural house, is a gas boiler, the author of this material shares his experience in repairing the automation of the gas boiler AOGV - 17.4-3, popular in rural areas, produced by the Zhukovsky Mechanical Plant.

Purpose and description of the main components of the AOGV - 17.3-3.

Appearance heating gas boiler AOGV - 17.3-3 is shown on rice. 1, and its main parameters are given in the table.

Parameter	Meaning
Dimensions (H×W×D), mm	1050×420×480
Weight, kg	49
Nominal thermal power, kW	17,4
Heated area, m 2 (no more)	140
Fuel type	natural / liquefied gas
Fuel consumption, m 3 /h, (kg/h)	1,87 (1,3)
Hot water consumption at 35 o C	5,4
Chimney diameter, mm	135
Nominal gas pressure, Pa	1274
Minimum gas pressure, Pa	635
Removal of combustion products	natural craving
Burner type	atmospheric
Heat exchanger material	steel
Type of installation	floor
Automation type	electrically independent

Construction of a gas boiler AOGV - 17.3-3

Its main elements are shown in rice. 2 . The numbers in the figure indicate: 1 - draft breaker; 2 - traction sensor; 3 - traction sensor wire; 4 -start button; 5 -door; 6 -gas magnetic valve; 7 -adjusting nut; 8 -tap; 9 -tank; 10 -burner; 11 -thermocouple; 12 - igniter; 13 - thermostat; 14 -base; 15 - water supply pipe; 16 - heat exchanger; 17 -turbulator; 18 - bellows unit; 19 - water drainage pipe; 20 - traction breaker door; 21 -thermometer; 22 -filter; 23 -cap.

The boiler is made in the form of a cylindrical tank. On the front side there are controls that are covered with a protective cover. Gas valve 6 (Fig. 2) consists of an electromagnet and a valve. The valve is used to control the gas supply to the igniter and burner. In case emergency situation the valve automatically turns off the gas. Traction breaker 1 serves to automatically maintain the vacuum value in the boiler furnace when measuring the draft in the chimney. For normal operation the door 20 should rotate freely on the axis without jamming. Thermostat 13 designed to maintain a constant temperature of water in the tank.

The automation device is shown in rice. 3 . Let us dwell in more detail on the meaning of its elements. Gas passing through a cleaning filter 2, 9 (Fig. 3) arrives at the electromagnetic gas valve 1 . To the valve using union nuts 3, 5 draft temperature sensors are connected. The igniter is ignited when the start button is pressed 4 . There is a setting scale on the body of thermostat 6 9 . Its divisions are graduated in degrees Celsius.

The desired water temperature in the boiler is set by the user using the adjusting nut 10 . Rotation of the nut leads to linear movement of the bellows 11 and rod 7 . The thermostat consists of a bellows-thermal bulb assembly installed inside the tank, as well as a system of levers and valves located in the thermostat housing. When the water is heated to the temperature indicated on the dial, the thermostat is activated and the gas supply to the burner is stopped, while the igniter continues to operate. When the water in the boiler has cooled down to 10 ... 15 degrees, the gas supply will resume. The burner lights up from the pilot flame. While the boiler is operating, it is strictly forbidden to regulate (reduce) the temperature with the nut 10 - this may cause the bellows to break. The temperature on the dial can be reduced only after the water in the tank has cooled to 30 degrees. It is prohibited to set the temperature on the sensor above 90 degrees - this will trigger the automation device and turn off the gas supply. The appearance of the thermostat is shown in (Fig. 4) .

How does the AOGV gas boiler turn on?

Actually, the procedure for turning on the device is quite simple, and besides, it is described in the operating instructions. And yet, let’s consider a similar operation with a few comments:

— open the gas supply valve (the valve handle should be directed along the pipe);

- Press and hold the start button. In the lower part of the boiler, a hissing of escaping gas will be heard from the pilot nozzle. Then light the igniter and after 40...60 and release the button. A similar time delay is necessary to warm up the thermocouple. If the boiler has not been used for a long time, the pilot light should be lit 20...30 s after pressing the start button. During this time, the igniter will fill with gas, displacing the air.

Possible malfunctions of the AOGV gas boiler

After releasing the start button, the igniter goes out. A similar defect is associated with a malfunction of the boiler automation system. Please note that operating the boiler with the automation switched off (for example, if the start button is forcibly jammed while pressed) is strictly prohibited. This can lead to tragic consequences, since if the gas supply is briefly interrupted or if the flame is extinguished by a strong air flow, gas will begin to flow into the room.

To understand the reasons for the occurrence of such a defect, let’s take a closer look at the operation of the automation system. In Fig. Figure 5 shows a simplified diagram of this system.

The circuit consists of an electromagnet, a valve, a draft sensor and a thermocouple. To turn on the igniter, press the start button. The rod connected to the button presses on the valve membrane, and gas begins to flow to the igniter. After this, the igniter is lit.

The pilot flame touches the body of the temperature sensor (thermocouple). After some time (30...40 s), the thermocouple heats up and an EMF appears at its terminals, which is sufficient to trigger the electromagnet. The latter, in turn, fixes the rod in the lower (as in Fig. 5) position. The start button can now be released.

The traction sensor consists of a bimetallic plate and a contact (Fig. 6). The sensor is located in the upper part of the boiler, near the pipe for exhausting combustion products into the atmosphere. If a pipe is clogged, its temperature rises sharply. The bimetallic plate heats up and breaks the voltage supply circuit to the electromagnet - the rod is no longer held by the electromagnet, the valve closes and the gas supply stops.

The location of the automation device elements is shown in Fig. 7. It shows that the electromagnet is covered with a protective cap. The wires from the sensors are located inside thin-walled tubes. The tubes are attached to the electromagnet using union nuts. The body terminals of the sensors are connected to the electromagnet through the housing of the tubes themselves.

Let's consider the method for finding the above fault.

Check during gas boiler repair they start with the “weakest link” of the automation device - the traction sensor. The sensor is not protected by a casing, so after 6...12 months of operation it becomes “overgrown” with a thick layer of dust. Bimetallic plate (see Fig. 6) oxidizes quickly, which leads to poor contact.

The dust coat is removed with a soft brush. Then the plate is pulled away from the contact and cleaned with fine sandpaper. We should not forget that it is necessary to clean the contact itself. Good results cleaning of these elements with a special spray “Contact” gives. It contains substances that actively destroy the oxide film. After cleaning, apply a thin layer of liquid lubricant to the plate and contact.

The next step is to check the serviceability of the thermocouple. It operates in severe thermal conditions, since it is constantly in the pilot flame; naturally, its service life is significantly shorter than other elements of the boiler.

The main defect of a thermocouple is burnout (destruction) of its body. In this case, the transition resistance at the welding site (junction) increases sharply. As a result, the current in the Thermocouple - Electromagnet circuit.

The bimetallic plate will be lower than the nominal value, which leads to the fact that the electromagnet will no longer be able to fix the rod (Fig. 5) .

How to check the thermocouple of an AOGV boiler

To check the thermocouple, unscrew the union nut (Fig. 7) located on the left side of the electromagnet. Then turn on the igniter and use a voltmeter to measure the constant voltage (thermo-emf) at the thermocouple contacts (Fig. 8) . A heated, serviceable thermocouple generates an EMF of about 25...30 mV. If this value is less, the thermocouple is faulty. To final check it, disconnect the tube from the electromagnet casing and measure the resistance of the thermocouple. 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 appearance of a thermocouple that failed as a result of burnout is shown in rice. 9 . The price of a new thermocouple (complete with tube and nut) is about 300 rubles. It is better to purchase them in the store at the manufacturer or use the services of an authorized service center. The fact is that the manufacturer is constantly improving its products. This is reflected in the parameters of the parts self-made. For example, in the AOGV-17.4-3 boiler of the Zhukovsky plant, starting from 1996, the length of the thermocouple connection has been increased by approximately 5 cm (that is, similar parts produced before or after 1996 are not interchangeable). This kind of information can only be obtained from a store (authorized service center).

A 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). They “treat” such a defect by cleaning the igniter hole with any soft wire of a suitable diameter;

— shifting the position of the thermocouple (naturally, it may also not heat up enough). Eliminate the defect as follows - loosen the screw securing the liner near the igniter and adjust the position of the thermocouple (Figure 10);

- low gas pressure at the boiler inlet.

If the EMF at the thermocouple terminals is normal (while the symptoms of malfunction indicated above remain), then check the following elements:

— integrity of contacts at the connection points of the thermocouple and draft sensor.

Oxidized contacts must be cleaned. Union nuts they are twisted, as they say, “by hand.” In this case spanner It is not advisable to use it, since you can easily break the wires suitable for the contacts;

- integrity of the electromagnet winding and, if necessary, solder its terminals.

The functionality of the electromagnet can be checked as follows. Disconnect the thermocouple line. Press and hold the start button, then light the igniter. From a separate source DC voltage a voltage of about 1 V is applied to the released contact of the electromagnet (from the thermocouple) relative to the housing (at a current of up to 2 A). For this, you can use a regular battery (1.5 V), the main thing is that it provides the necessary operating current. The button can now be released. If the igniter does not go out, the electromagnet and draft sensor are working;

- traction sensor

First, check the force of pressing the contact against the bimetallic plate (with the indicated signs of malfunction, it is often insufficient). To increase the clamping force, release 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 response temperature of the sensor. The sensor has a large margin of plate deflection angle, ensuring reliable breaking of the electrical circuit in the event of an accident.

It is not possible to light the igniter - the flame flares up and immediately goes out.

There may be the following possible reasons similar defect:

- closed or faulty gas tap at the boiler inlet,
— the hole in the igniter nozzle is clogged, in this case it is enough to clean the nozzle hole with soft wire;
— the igniter flame is blown out due to strong air draft;

The gas supply is turned off when the boiler is running:

- the draft sensor is triggered due to a clogged chimney, in this case it is necessary to check and clean the chimney;
— the electromagnet is faulty, in this case the electromagnet is checked according to the above method;
- low gas pressure at the boiler inlet.

From this article you will learn what problems can arise in the automation of gas boilers, why it is impossible to ignite the igniter, which is why the boiler can turn off for no reason, and most importantly, we will figure out what actions need to be taken to diagnose and eliminate this malfunction.

Owners of non-volatile gas boilers are probably familiar with the situation when, for some reason, it is not possible to ignite the boiler, or a lot of time is spent on ignition. In this case, the problem lies in the boiler automation.

Today, the gas valve EUROSIT 630 is most often used in domestic and imported gas equipment. It is this valve that performs the functions of maintaining set temperature coolant and, in the event of an emergency, completely shuts off the gas supply to the burners. Further starting of boilers with such automation is only possible manually. However, the cause of a boiler emergency shutdown is not always a real accident.

Let's try to understand this using the example of the Zhitomir-3 boiler. Automatically, it provides protection against loss of flame on the igniter and loss of traction.

Note: All gas-hazardous work must be carried out exclusively by representatives of specialized organizations that have the appropriate permits. Therefore, this article is provided for informational purposes only. This article will also help you monitor the work of the technician and, perhaps, save you from the need to purchase unnecessary spare parts.

Let's decide what we will call igniting the igniter. The EUROSIT 630 valve control knob allows you to switch the boiler to three main modes:

• disabled;
• ignition;
• temperature adjustment (1-7).

To ignite the pilot burner (igniter), you must move the control knob to the “ignition” (spark) position, press it and use the piezo ignition button to ignite the pilot burner. Next, the handle is held for several seconds (no more than 30) and released. The pilot light should continue to burn. This is what we will call igniting the igniter. If the pilot light goes out, you need to repeat the procedure several more times. If this does not help, you need to look for the problem.

At the moment the igniter is ignited, the flame heats the thermocouple, which in turn generates an EMF (approximately 25 mV for working SIT thermocouples), which is supplied through the automation sensor(s) circuit to the solenoid valve.

By pressing the gas valve handle, we manually open the solenoid valve, supplying gas to the igniter, which, if proper operation equipment, is held by the EMF generated by the thermocouple and remains in the open position after the handle is released. The thermocouple itself performs the function of protecting against loss of flame on the igniter. The sensors located in the circuit are normally closed and, when triggered, open their contacts, ensuring complete shutdown of the boiler.

Preparing for work

To carry out work to identify and eliminate problems with igniter ignition, we will need the following tool:

• open-end wrenches No. 9, 10, 12;
• pliers;
• multimeter;
• flathead screwdriver;
• alcohol.

Let's get started

To determine the cause of the malfunction, we will check the thermocouple circuit - solenoid valve. First, let's check the traction sensor. In this boiler it is located on the gas duct. To do this, remove two terminals from the sensor.

We close the two terminals together, they should connect tightly (to do this, you can press them a little with pliers).

We are trying to ignite the igniter. If this was possible, the cause of the malfunction is in the traction sensor. However, do not rush to change it. First, let's check it.

Note: In this work, we dismantle the sensor in order to show the features of its installation on the boiler and its markings. This is not necessary for verification.

Unscrew the two screws securing the draft sensor to the boiler flue.

Please note that the sensor is not attached tightly to the flue body, but is mounted on paronite gaskets. This is necessary in order to reduce heating of the sensor through its contact with the body, and also to ensure a gap between the hole in the flue duct and the plane of the sensor.

We inspect the sensor. Its contacts must be firmly attached to the body. There should be no oxidation on them. The sensor rating (the temperature at which the sensor contact opens) in this case is 75 °C (designation on the housing L75C).

We check the traction sensor with a tester, measuring its resistance. It should be minimal (equal to the resistance of the probes) - 1-2 Ohms. If the sensor does not ring, it is clearly necessary to replace it with a similar one (with the appropriate response temperature).

If the sensor was able to ring, wipe the contacts of the sensor and the circuit terminals with alcohol, tighten them with pliers and dry them. We mount the sensor in place and connect it. We are trying to ignite.

If ignition was successful, the cause of the malfunction has been found and eliminated.

Be sure to check the draft after igniting the main burner. To do this, you can bring your hand to the place where the traction sensor is installed. No heat should come out of this hole. If this happens, it is necessary to eliminate the cause causing insufficient traction. In this case, the sensor works correctly.

Attention! Operating a boiler with a faulty chimney is strictly prohibited!

We remove the terminals from the contacts of the traction breaker and measure the resistance of the circuit. It should be no more than 3 ohms.

If this condition is met, we perform the following actions. Using wrench No. 9, unscrew the nut securing the thermocouple to the traction breaker. Using wrench No. 12, unscrew the traction breaker, which consists of two parts: a brass sleeve and a plastic insert, by half a turn.

We take out the plastic insert with contacts and unscrew the part completely.

Checking the thermocouple. We connect it directly to the solenoid valve (the place where the traction breaker was installed). We fix it with key No. 9.

We ignite the igniter. If it fails, the cause of the malfunction is most likely in the thermocouple. Solenoid valve It rarely fails.

Let's examine the thermocouple. In some cases, the thermocouple can be repaired. It happens that the thermocouple contact disappears. This is not a reason to replace it, just solder it.

It is important that the dielectric gasket is intact.

Make sure the thermocouple is positioned correctly in the pilot flame. The tip of the thermocouple should be immersed in the flame.

To adjust the position of the thermocouple relative to the igniter flame, use a No. 10 wrench to loosen the nut securing the thermocouple to the pilot burner. When moving the thermocouple, it is necessary to install it in the correct position and fix it with key No. 10.

To make a final verdict on replacement, you can measure the EMF generated by the thermocouple. To do this, it is necessary to ignite the igniter, and, holding the valve handle pressed, measure the EMF between the thermocouple contact and its body. The optimal value should be at least 18 mV. If the thermocouple is working, clean the parts of the traction breaker with alcohol, and also wipe the contact of the thermocouple. Especially if it had to be soldered.

We assemble the traction breaker in the reverse order and connect a thermocouple to it. The parts should not be pressed too hard. The effort must be sufficient to ensure reliable contact. We crimp the terminals with pliers and, after wiping them with alcohol, try to ignite.

Performing all the above steps will surely help you troubleshoot your boiler.

Another cause of problems with ignition may be insufficient gas pressure on the igniter. This occurs due to a clogged nozzle. To clean it, you need to use a No. 10 wrench to loosen the fastening nut. copper tube igniter and remove the nozzle.

Advice: You can lightly tap the igniter to make it easier to remove the nozzle.

Cleaning the hole in the main jet copper wire. Violation of the hole size is not allowed!

At moments of the most intense gas consumption, the pressure in the central main pipe may drop. Accordingly, the gas pressure at the igniter may also decrease. This may require adjusting the gas pressure at the igniter. Unscrew the screw securing the decorative trim and remove it.

The adjustment is made by turning the screw on the valve. When turning it counterclockwise, the gas pressure on the igniter increases.

These tips will help you deal with problems with ignition of your boiler. In practice, the most common problems are with the contacts, and not with the sensors. Therefore, if each time you ignite the igniter you have to hold the valve handle longer and longer, we advise you to simply clean the contacts and tighten the automation terminals. In order to avoid real problems with the operation of the automation, we recommend cleaning the boiler in a timely manner.

If your gas boiler goes out and blows out, then you should study a number of reasons that can cause this problem, and then take action as quickly as possible necessary measures, aimed at stabilizing and restoring normal operation of the boiler.

We propose to familiarize yourself with the eight main causes of such problems and their solutions.

Gas boiler wick

The wick burns weakly for two reasons: either it is clogged and needs to be cleaned, or you have weak inlet pressure. If you have a home controller, be sure to check its settings. You may need to increase the inlet pressure, as it constantly fluctuates due to the fact that gas consumption is different in different periods.

Accordingly, in heating season, When gas boilers operate, gas consumption is higher and the inlet pressure also drops. And the regulator, as far as you know, maintains a certain differential between the inlet pressure and the outlet pressure. Accordingly, this differential also drops, because of this your wick may burn weaker. Check the regulator setting and also clean the wick.

2. The flame control sensor has failed

Thermocouple

This is the next reason why a gas boiler may go out. The control sensor is different in different boilers. In most home boilers this is a thermocouple. The thermocouple must always be on fire, just as the ionization electrode and photosensor must always detect the flame on your burner. If the thermocouple is in a worn-out condition, then with any slight blow of wind, when your wick deviates very slightly from this thermocouple, it immediately knocks out the automation and your gas boiler goes out.

If you have an ionization electrode, a similar situation occurs. Ionization electrodes are usually installed in volatile double-circuit boilers which hang on the wall. Photosensors are installed in boilers of higher power. But this is, in principle, an industrial type of boiler, which is quite rare in ordinary homes.

3. Poor draft in the chimney

This suggests that either some kind of debris has fallen into it, or some brick has fallen, or a bird flying by has inhaled carbon monoxide, coming out of the chimney, turned out to be disoriented in space and fell straight into your boiler, or a spider could have settled there and the web it created tangled up the entire chimney. Accordingly, the chimney must be cleaned in order to improve draft. There will be good draft and the wick will not go out. If a gas boiler goes out, this is one of the common solutions.

4. One-story building or top floor

This makes it easier for wind to get into your boiler. In order to avoid attenuation of the wick in a gas boiler with such a chimney arrangement, it is necessary to protect the chimney head, that is, install special protective devices- washers.

Please note that visors in the form of umbrellas, which may be found on certain houses, are strictly prohibited according to gas supply safety rules. This is due to the fact that as the snow melts, the resulting water immediately begins to gradually flow down and form icicles on the burning chimney. Thus, the chimney can be completely blocked. That's why they put washers. They seem to stand around the head of the chimney and thus protect it from the wind.

Another way to protect yourself from attenuation and blowing out of a gas boiler with such a problem is to increase the number of turns of the chimney. If your chimney comes out of the boiler and directly into the wall, then in order for the wind to get there, it is enough to overcome only one turn. That is, the junction between your chimney and boiler.

If you increase the number of turns in your boiler, it will be much more difficult for the wind to reach your gas boiler and the likelihood of blowing will be less.

5. Insufficient supply ventilation or lack of a ventilation duct

When one cubic meter of gas is burned, ten cubic meters of air are burned. Accordingly, in most cases at home domestic boilers, if it is not a turbine type of boiler with a coxial tube, air from the room is used.

And, accordingly, if you have insufficient supply ventilation: the door is not cut, or holes are not made, and your room is constantly closed, then the air flow is not enough for the boiler to burn.

Or ventilation duct you may not have it, or you may simply have it clogged. Again, you need to either clean the ventilation duct or ensure air flow from below. This is necessary in order to burn required quantity air in the room and your gas boiler does not go out. If you do not have supply ventilation, or there is no draft in the ventilation duct, then the boiler will begin to burn air from the room. When all the air in the room is burned, it will begin to take in air from the street through the chimney. Thus, reverse thrust is formed. A certain draft forms and this draft can blow out your boiler.

6. Pilot safety circuit problem

The safety circuit is mainly represented by either a traction sensor or a limit thermostat - special devices that are able to detect any problems in time.

All protective equipment located there must be checked. Often these contacts become sour and need to be cleaned thoroughly. If you have sour contacts somewhere, then there will be no interaction. If there is no contact when you try to light the wick, you will simply knock out the automation.

If the wick of a gas boiler deviates slightly from your ionization electrode or thermocouple, the voltage that remains on your sensor may simply not be enough to keep the valve open and the wick goes out. Therefore, it is imperative to check the safety circuit contacts of your boiler. This is a draft sensor, a limit thermostat, and a thermocouple.

7. The chimney is located in the area of ​​wind pressure

Wind pressure zone

What is a wind support zone? In fact, this seemingly complex concept can be explained quite simply and clearly. If there is a tall building or tree next to your chimney, then the wind pressure zone is a line that can be drawn from this nearby building or tree towards your chimney.

That is, we draw a line from the building towards your chimney, visually 45 degrees, and your chimney should be half a meter above this imaginary line. If your chimney is located lower, then turbulence may form in the chimney and the boiler will go out.

According to gas supply safety rules, the chimney must be outside the zone of wind pressure. And considering that these rules were invented for a reason, it is worth following them.

8. Incorrect location of the gas boiler in the room

The location of the gas boiler in the room also plays a role important role. In some cases, situations have been observed when, for example, the boiler is located in the kitchen, which in turn is located somewhere on the second or third floor of the building and this kitchen has a balcony.

So what's going on? People open the balcony door, the draft in the chimney is excellent and... What happens? At first we had some influx of air from the corridor or from neighboring rooms when the door in the kitchen was opened, and the draft was more or less stable. And then, when the balcony suddenly opens, what happens? A huge amount of fresh cold air enters the kitchen and a very sharp strong draft is formed in the chimney.

The amount of air increases and hot air begins to flow into the chimney at an even greater speed. Thus, the wick literally begins to fluctuate and wander. That is, it can simply either be blown away, or if there are bad contacts of the safety circuit, or worn out sensors. This can also lead to your boiler going out.

It is worth noting that the above reasons are the most common problems. There may be special cases when the cause of the gas boiler fading and blowing out can only be determined by a specialist after a thorough examination.

Only one thing is important - follow the gas supply safety rules and comply with the standards prescribed there.

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