The function of the gas column igniter is to ignite the burner when the water tap is opened. That is why it is very important that the igniter works without interruption. Often a small fire is also called a wick. Combustion of the air-fuel mixture creates a fire. If the igniter is extinguished, the geyser will stop the gas supply. This happens to prevent its accumulation. Consider in our article why the gas column igniter goes out, as well as ways to eliminate it.
- Why does the gas column igniter go out
- Troubleshooting
- Repair of a gas burner with an automatic protection system
- Elimination of automatic protection system
There are several reasons why the igniter goes out:
- No draft in the chimney.
- The thermocouple is worn out or burnt out.
- The wick is clogged with dust.
- Breakaway flame.
- The traction control sensors are out of order.
- There is poor contact between the control unit and the sensor.
- The ionization sensor is outside the flame area.
The most common cause of an igniter going out is a thermocouple failure. When the igniter goes out, there is a lack of heat, since there is no fire, the thermocouple detects it and turns off the gas. Thermocouple - an element that is designed to turn off the gas in case of intermittent operation of the geyser. But after long-term use, the thermocouple can burn and its tip will become loose from prolonged exposure to fire. This is what causes the igniter to go out.
If there are any air currents from the outside, then they can blow out the igniter. If the device has improper ventilation, then air flows can come from it, which extinguish the igniter. But many confuse such a problem with a lack of traction. Therefore, during the repair, you need to correctly identify the problem.
The gas control system includes solenoid valves. They are arranged in geysers. In the event that the ventilation ceases to function, then carbon monoxide begins to flow into the room. And the solenoid valves shut off the gas supply and the igniter goes out.
Over time, black soot settles on the heat exchanger and the platform around the igniter. This is another reason for the extinguishing of the igniter. As a result of incomplete combustion of gas, soot is formed. Due to the accumulated soot, problems often form with the air ventilation system. As a result, the extinguishing of the igniter occurs.
Troubleshooting
First of all, it is necessary to wash the filters or replace them with new ones. You can do it yourself. Next, you need to call specialists who will find out why you have no water pressure in the system. After clarifying the problem, specialists will clean the column from soot or wash the pipes. It is also possible to replace the membranes on the water node.
Another reason that the gas burner does not ignite is discharged ignition batteries. There are times when the gas column ignites and immediately goes out. In order to solve this problem, you need to adjust the supply of cold and hot water. But you can not dilute hot water with cold. This leads to the extinction of the flame, and is also an incorrect use of the geyser. In order to adjust the supply of cold water, it is necessary to reduce its supply at the tap by turning the valve.
There is also such a problem: the geyser turns on with pops and immediately goes out. This problem may occur due to clogging of the jet or any other elements of the column, lack of traction, discharged batteries for ignition, strong gas flow. You can fix such problems yourself or invite a specialist.
Repair of a gas burner with an automatic protection system
Consider the more serious problems of extinguishing a gas column, which has an automatic protection system.
The gas in the igniter must burn continuously, regardless of the position of the faucet valve, water mixers and handles. In a geyser with a conventional automatic protection system, the following elements are built in: a tremoprotector, a thermocouple and an electromagnetic valve. If the igniter is clogged or the thermocouple does not work, then the wick of the gas column is attenuated, as the protection systems are triggered.
After you stop holding the gas control knob, the igniter goes out. In this case, the automation system does not work. To repair such a problem, you need to have a good understanding of how the protection system node works. If you do not understand this, then it is better to invite a specialist to fix the breakdown.
Troubleshooting the automatic protection system
- Repair of a geyser and a thermal protection relay. To check the operation of the thermal fuse, you need to remove the terminals and short them to each other with some kind of metal elements. For example, you can use a paperclip. The malfunction will be eliminated if the geyser starts to work normally and does not overheat.
- Checking the operation of the column solenoid valve. If the first option did not fix the problem, then you need to check the operation of the solenoid valve. Such a valve has a resistance that is 0.2 ohms. To check the solenoid valve, you must perform the following steps: apply voltage to the winding with a power of 20 to 30 mV at a current of 100 mA. This mode can be easily created with a 100 m resistor or a finger battery. Next, you need to set fire to the wick and remove your hand from the gas control knob. The wick should burn, and after disconnecting the battery, it should go out. In this case, the solenoid valve is working properly. If all elements are working properly, then the cause is a malfunction of the thermocouple. If by outward signs there is no problem, the thermocouple must be replaced with a new one.
- Gas column igniter repair. You can try to clean the nozzle or air supply hole with a thin wire. After that, the igniter should start working. After some time, the nozzle becomes clogged with soot. Therefore, the flame becomes insufficient, which means the fire can go out and not ignite. As a result, gas accumulates and an explosion can occur. Therefore, it is necessary to clean the igniter. If there is not enough oxygen in the gas mixture, the burner will glow yellow. To eliminate this problem, you need to clean the holes in the igniter in order to receive a sufficient amount of oxygen.
It is always necessary to accurately determine the cause of the extinguishing of the gas column igniter. When a thermocouple or other elements of the burner fails, you need to be careful.
If you cannot repair it yourself, then it is better to contact specialists. After all, improper repair of a gas burner can lead to serious consequences.
Read also:
Geyser Termet - Faults and solutions
Lack of ignition
If a model equipped with electric ignition is installed, for example, Termet G 19-00 Aquaheat Electronic, the water heater may not turn on if the batteries are dead. If, when a hot water tap is opened, the device creates a spark, this is heard by a characteristic sound. But the power of the spark may not be enough to ignite the flame.
To solve this problem, you need to install new batteries. R20 batteries are suitable for this model. It is recommended to install alkaline batteries, as their life is much longer. The installation location is located at the bottom of the device on the left side.
If a semi-automatic geyser, such as Termet Termaq G 19-01, is installed, then the igniter jet or piezo ignition wire may be clogged. To solve this problem, it is necessary to dismantle the casing of the device in order to clean the wires. If dust has accumulated in the jets, the igniter may not burn. It can be cleaned using a thin soft wire. For high-quality ignition, it is important that the piezo ignition button is held for at least 5 seconds.
Also, ignition will not occur if the wick or ignition electrodes are not installed correctly. Due to frequent temperature changes, the elements of the device may be deformed. This affects the geometry of the electrodes and the wick in space. To solve the problem, it is necessary to visually inspect the problem areas, and, if necessary, install them in the correct position.
Also, the flame may not appear if the membrane of the water node is damaged. When water enters under its pressure, the membrane bends and, by pressing on the stem, it opens the gas supply valve. Deformation or damage to the membrane leads to the fact that the gas stops flowing into the burner. For repair, it is required to remove water from the unit.
To do this, it is necessary to disconnect the water supply and drainage pipes from the water unit. It is also necessary to dismantle the heat exchanger. After that, you need to remove the bolts holding the cover of the water unit. The membrane can then be removed. To replace, you must purchase exactly the same model as installed in your device.
With low water pressure in the water supply, the Termet geyser will also not work. The minimum allowable value is 0.1 bar. First you need to set the pressure regulator on the device to the lowest value. The regulator is located to the right of the temperature control knob. It is marked with a blue stripe. And if the problem is in the water supply pressure, then when you open the supply valve in the water main, you can observe a weak pressure. To solve the problem, you need to call the provider of this service.
Another reason why the water heater may not ignite is an emergency shutdown due to a signal coming from the draft sensor. It is installed at the top of the appliance, and works if no combustion products are discharged into the chimney. In this case, the flame at the beginning lights up, but quickly goes out. Draft can be tested with a candle or match flame. If the draft is broken, the chimney needs to be cleaned.
The flame may go out due to the operation of the protection if there is too powerful a hood installed above the unit. A clogged heat exchanger can also cause the problem described above.
How to light the device correctly
First of all, the algorithms for turning on the Termet gas column are determined by the way it is ignited.
It is divided into two types. Termet G 19-00 Aquaheat - Ignition is carried out using batteries. In this model, there is no need for a constantly burning igniter. All adjustments in terms of power and pressure are automatic.
Termet Termaq G 19-01 - this model has a piezo ignition. The main difference of this model is a continuously burning igniter. Separately, you can adjust both the water pressure and the power. The adjustment knobs are located on the front of the machine.
Very often, the instructions that come with the column are very incomprehensible, so here are the key points you need to know to turn on the Termaq G gas instantaneous water heater with piezo ignition.
The Termet 19-01 geyser has a flame control sensor, a draft control sensor and an outlet temperature limiter. The unit is connected to a chimney through which exhaust gases are discharged. The device itself is made of stainless steel. The heat exchanger in it is installed copper, without any impurities of tin and lead.
All water fittings are made of glass fiber reinforced environmentally friendly polyamide. On the front panel you can see a viewing window, a power regulator, a knob that allows you to adjust the water. The piezo ignition button is installed at the bottom of the water heater. Before you start working, you need to make sure that there is enough air entering the room, and there is a draft that removes exhaust gases.
During its operation, the Termet geyser burns a large amount of oxygen, so the flow of fresh air must be very good. Next, you need to open the shut-off valve on the gas line and the cold water line. To turn on the device, it is necessary to hold the power regulator button with one hand, and at the same time press the piezo ignition with the other hand. This produces a spark that ignites the ignition burner. It is important to observe safety measures and not come close to the viewing window.
The piezo ignition button must be held for at least 15 seconds. It is this time that is needed for the thermocouple to warm up properly and give a signal to the burner to start. After the pilot flame has ignited, the piezo ignition button can be released. If ignition does not occur, you need to repeat the procedure. If the unit has been standing for a long time and air has entered the system, it is necessary to keep the power control button pressed so that all the air is expelled.
The power of the water heater is set independently, since this model does not have a Power control system. This is done by moving the slider left and right. To the right is the maximum value, to the left is the minimum. The water temperature is adjusted using the water volume knob. Turning the knob anti-clockwise increases the water flow and therefore decreases the temperature, and vice versa.
Geyser Bosch
When the appliance is turned on again, the main burner will start automatically as soon as there is a request for water from the collapsible tap. In this case, the pilot flame will burn continuously. When the demand for hot water stops, the unit also turns off. If you plan to stop the machine for a very long time, you must turn the power control knob to the minimum position.
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For over 100 years people have been using gas water heaters in order to prepare hot water for sanitary and hygienic purposes. The most widely used instantaneous water heaters, or, as they are most often called, columns. The most important node of this device is the heat exchanger. It is in it that what the column is intended for happens. The products of gas combustion, passing from bottom to top along the internal cavity of the heat exchanger, give off heat to water moving through copper tubes. To ensure good heat transfer, the heat exchanger casing, pipes and fins of the heat exchanger radiator part are made of copper, which has a high thermal conductivity. The thermal conductivity coefficient of copper is 7.3 times higher than that of steel.
That is why heat exchangers, usually made of copper, are installed in geysers. To prevent their premature wear, the surfaces of heat exchangers and tubes are coated with a metal resistant to corrosion. For the same purpose, and for safety reasons, modern gas water heaters are equipped with the necessary automation equipment.
For example, on RIHTERS columns, as well as on columns from other manufacturers, special sensors are installed that will give a signal to stop the gas supply to the burner in the following cases:
. Unforeseen extinction of the flame
. Draft problems in the chimney
. Water supply interruptions
The column will also turn off when the maximum heating temperature is reached - 80C. It would seem - everything is provided.
However, there are times when columns fail due to burnout of the heat exchanger casing. The first reaction of the consumer is often: "The column is bad, the manufacturer is to blame." There are sometimes “consultants” who say: “This device is of poor quality, the manufacturer is to blame. Now, if you had bought a column from another manufacturer, this would not have happened. Do not rush to draw conclusions. Today, more than 250 thousand columns are operated in the Republic of Belarus, and they fail due to the burnout of the heat exchanger casing - thousandths of a percent. Among them are columns different manufacturers. And in the vast majority of cases, the fault of manufacturers is not there.
What is the reason?
This phenomenon is based on a banal simple truth: local overheating of the surface of the heat exchanger. But why this is happening, you need to understand.
There may be several reasons:
1. The presence of scale deposits in the heat exchanger tubes. Dissolved water contains hardness salts. When such water is heated, scale forms on the inner surface of the heat exchanger tubes, which impairs the transfer of heat from the combustion products to water. If your column has served for 2 years or more, you can be sure that there is scale on the inner surface of the tubes, and its thickness is constantly increasing. To achieve the water temperature you set, each time the burner flame is forced to increase with an adequate increase in gas flow, i.e., the heating intensity of the heat exchanger surface increases. If preventive measures are not taken, the result is inevitable - sooner or later the heat exchanger casing will burn out, it all depends on the thickness of the scale.
2. Gas pressure in front of the device. The speakers installed in the Republic of Belarus are designed for operating pressure gas in front of the column burner at 1274 Pa. In accordance with the requirements of GOST 19910-94, they are tested for operation at a gas pressure in the range of 640 - 1764 Pa. At a gas pressure below 640 Pa, the column operates with reduced power and may turn off altogether. Gas pressure above 1764 Pa (which, unfortunately, often takes place) creates conditions for a strong flame, which, as they say, “licks” the walls of the heat exchanger, and this leads to local overheating and burnout of the heat exchanger wall.
3. Unsuccessful choice of a column in terms of power, more precisely, an underestimated power of the column. For example, you have a 16 kW column, which is designed to heat water up to 8 l / min. And you want to fill the bath with hot water as soon as possible, and at the same time wash the dishes with parsing from the tap 5-6 l / min. In such a situation, you are forced to turn on the column at full power for a long time. And such a forced mode does not have the best effect on the service life of the device - there is a strong heating of the heat exchanger and intensive scale deposition.
4. A phenomenon similar to paragraph 3 occurs when you unnecessarily turn on the column at full power and heat the water to the maximum value, and then mix it with cold water to get a comfortable temperature.
Geyser device and principle of operation
Pay attention to correct installation. The column must be strictly vertical. Installing it with distortions leads to an uneven distribution of the flame inside the heat exchanger and local overheating, which creates a risk of burnout of the heat exchanger.
In order to prevent the heat exchanger from burning out:
1. Regularly, at least once every 2-3 years (depending on the hardness of the water), invite a specialist to flush the heat exchanger. Washing costs will pay off with a vengeance. Not only will you minimize the risk of burning, flushing reduces gas consumption.
2. Choose the right speaker for power. Before buying, consult with experts.
3. Check the correct hanging of the column.
5. Do not set the water temperature above 50 degrees, this will drastically reduce the formation of scale in the heat exchanger tubes.
If, unfortunately, your column has burned out, at the departure of a gas service specialist, urgently demand that the gas pressure in front of the device be measured in your presence and documented.
The pressure should be in the range of 640 - 1764 Pa.
Instructions for troubleshooting gas column Neva 4511
Thermocouple for a gas boiler: principle of operation, characteristics, troubleshooting
- Device, principle of operation and main types
- Thermocouple in the gas control system (gas control)
- Connecting, testing and troubleshooting
Introduction
The use of gas for heating a private house or cottage is very convenient and cost-effective. However, this type of fuel is fraught with a serious threat. If, for any reason, the burner suddenly goes out and the gas supply is not shut off in time, a leak will form and this can turn into serious trouble and endanger the lives of people in the room. In order to immediately turn off the gas if the flame suddenly goes out and a thermocouple for a gas boiler is used.
In this article, we will talk about what a thermocouple is, why it is needed and how it works, consider the main types and most common malfunctions associated with these devices, as well as a method for eliminating them.
Device, principle of operation and main types
A thermocouple is a classic thermoelectric transducer, which is used to measure temperature in various fields of industry, science, medicine, as well as in automatic systems management and control of gas boilers, stoves and columns.
It is arranged very simply and can be easily made independently. Two conductors from various materials join in a ring. One of the connection points is placed in the measurement area, and the second is connected to the measuring instrument or converter.
The principle of operation of a thermocouple is based on the thermoelectric effect, or as it is also called the Seebeck effect. It lies in the fact that at the junction of two conductors connected in a ring from different metals tension appears. If the temperature of the soldering points is the same, the potential difference is zero. But as soon as one of the junctions is placed in an area with a higher or lower temperature, a voltage appears that is different from zero and proportional to the temperature difference. The coefficient of proportionality is different for different metals and is called the thermo-EMF coefficient.
The main materials for the manufacture of thermocouples are noble and base metals. Most alloys of them have quite exotic names, which are very popular with the compilers of various crosswords and scanwords. Depending on which metal pairs are used in the manufacture, thermocouples are divided into several types. Below is a table with their main types, designations and characteristics:
In automation systems geysers, stoves and boilers, thermocouples TXA from chromel-alumel (type K), THC from chromel-copel (type L), TGK from iron and constantan (type J) are usually used.
Gas boiler draft sensor: principle of operation, performance test
Precious metal alloy sensors are designed for high temperatures and are mainly used in foundries and other heavy industries.
Some solid fuel models, such as the Lemax Forward solid fuel heating boiler, can be equipped with gas burners which use thermocouples to protect against gas leaks.
Now we will understand the purpose of a thermocouple in a gas boiler, its features and principles of operation. In the end, we will figure out how to carry out repairs with our own hands.
Any boiler, regardless of the type and principle of its operation, needs a thermocouple - a device that will control the temperature in the combustion chamber and automatically shut off the gas supply when the flame disappears.
For a gas boiler, it is a necessary element in the heating system, which helps to avoid overheating of the boiler and the possibility of its breakdown.
Thermocouple for gas boiler
To understand how a thermocouple works in a gas boiler, you first need to get acquainted with its device and principle of operation.
A thermocouple is a construction of two conductor plates, which consists of different alloys. The device is quite simple, but at the same time reliable.
The principle of operation of this device is based on a physical phenomenon - the Seebeck effect.
The process of formation of an electromotive force at the junction of two dissimilar conductors, the contacts of which have temperature differences. Seebeck effect
If two parts made of dissimilar metals are firmly connected, and the junction is heated, then a potential difference will appear at the cold ends of the soldered conductor - voltage. When voltage is applied, the valve automatically opens immediately, allowing fuel to pass to.
The principle of operation of a gas boiler thermocouple
Types of thermocouples
Today, the market for boiler equipment is characterized by an abundance of various thermocouples, which are divided into several types. The metal used in their manufacture is the main criterion on the basis of which they are differentiated.
From base metals
| Thermocouple type | Alloy | Russian marking | Temperature range, °C | Thermocouple Features |
|---|---|---|---|---|
| K | chromel-alumel | TXA | from -200 °С up to +1000 °С | Ability to work in a neutral atmosphere or an atmosphere with excess oxygen |
| L | chromel-copel | TXK | from -200 °С up to +800 °С | The highest sensitivity of all industrial thermocouples. Only high thermoelectric stability is characteristic at temperatures up to 600 °C. |
| E | chromel-constantan | TXKn | from -40 °С up to +900 °С | High sensitivity. |
| T | copper-constantan | TMKn | from -250 °С up to +300 °С | It can work in an atmosphere in which there is a slight excess or lack of oxygen. Not sensitive to high humidity. |
| J | iron-constantan | TGK | from -100 °C up to +1200 °С | Works well in a discharged atmosphere. The low cost is due to the iron included in the composition. |
| A | tungsten-rhenium | TVR | above +1800 °С | Good performance mechanical properties at high temperature. It can work with frequent and abrupt heat changes and under heavy loads. Unpretentiousness in the manufacture and installation, as they have a slight sensitivity to pollution. |
| N | nihrosil-nisil | TNN | from -200 °С up to +1300 °С | In the group of base metals, it is considered the most accurate thermocouple. High stability at temperatures from 200 to 500 °C. |
From precious metals
| Thermocouple types | Alloy | Russian marking | Temperature range, °C | Thermocouple Features |
|---|---|---|---|---|
| B | platinum-rhodium-platinum-rhodium | TPR | from +100 °С up to +1800 °С | High mechanical strength. Greater stability at high temperatures. Slight tendency to grain growth and brittleness. Low sensitivity to pollution. |
| S | platinum-rhodium-platinum | CCI10 | from 0 °C up to +1700 °С | High measurement accuracy. Good reproducibility and stability of thermoEMF. |
| R | platinum-rhodium-platinum | CCI14 | from 0 °C up to +1700 °С | It has the same properties as type S thermocouple. |
In boiler automation systems, thermocouple types are more often used: E, J, K.
Connection and verification
The thermocouple must be connected using electrodes (wires) made of the same material as the connected thermocouple.
Alternatively, metal wires may be used that have characteristics similar to those of the electrodes on the thermocouple itself.
Before connecting thermocouples for heating boilers, it is important to strip the ends of the wires to remove oxides that affect the accuracy of measurements. And during installation, it is important to ensure that the fuel outlet and supply pipes are lowered straight down.
In case the thermocouple is broken, it is usually impossible to restore it, so it is important to know how to check the thermocouple with a multimeter on a gas boiler.
The working thermocouple should work after 10-30 seconds of heating
To check its performance, it is enough to connect one end to a multimeter - a measuring sensor, and heat the other end using either a lighter.
A combined electrical measuring device, which can be digital and analog, combines several functions (at least the functions of a voltmeter, ohmmeter, ammeter). multimeter
The working thermocouple should have a voltage in the region of 50 mV.
If a thermocouple malfunction is confirmed, you can replace it yourself.
Do-it-yourself thermocouple repair
To fix the problem yourself, you need to:
- unscrew clamping nut wrench and and get her end;
- lacing-zero clear of dirt;
- check the thermocouple with a multimeter;
- make sure that all indicators comply with the standards;
- assemble the thermocouple back and start the boiler.
If you can't fix the thermocouple, you can always buy a new one. The Russian market offers a wide range of these devices manufactured by various manufacturers, for example, ABAT, AOGV, AKGV. Their price ranges from 300 to 2000 rubles. For foreign-made gas boilers (for example, Bosch, Viessmann, Vaillant), the price of a thermocouple will be higher.
Today, thermocouples have found active use in, their choice on the market is great, and everyone has the opportunity to purchase a universal thermocouple. However, choosing a thermocouple on your own, you may encounter a number of difficulties. You should contact a specialist who will tell you how to choose a device that meets all the characteristics of a gas boiler. You can also use the dependency table specifications device with the characteristics of a gas boiler.
The gas boiler is complex structure which needs additional components. Particularly important in this device are parts that control its operation and protect against overheating. One of the most important components of a gas boiler is a thermocouple. Let's see what it is and how to repair it with your own hands.
What is a thermocouple for a gas boiler
To understand how a thermocouple works, you must first define what it is. Only in this case you will be able to change it in case of a malfunction and check its operation.
A thermocouple is an element not only of a gas boiler, but also of a column. It is thanks to it that the safety of the operation of gas equipment is ensured.
You can find the answer to the question: "What is a thermocouple?", in special documentation. However, we offer you an explanation of the device of this element in a simple language.
What is a thermocouple:
- The thermocouple is a device for monitoring equipment. It consists of two conductors of different types.
- Thermocouple conductors must be in contact with each other. Such contact is provided at one or two points of the device.
- Due to the different types of conductors in a thermocouple, when heated, they create a voltage between themselves. This voltage is taken into account during the operation of the gas boiler.
- It is thanks to the conductors and their characteristics that you do not have to use external excitation of a gas boiler. These parts can be powered autonomously.
Thus, the thermocouple is a temperature control sensor in the boiler. It has a very simple device, due to this, its versatility is ensured.
There is only one rule regarding the choice of thermocouple. When buying such a device, you need to pay attention to the quality of fixing the connection points of the conductors. If this parameter is performed poorly, then the device may give an error of more than one degree. This is an unacceptable indicator for gas equipment.
How a thermocouple works
If you want to learn how to repair and troubleshoot a thermocouple, you must first understand the principle of its operation and understand how it works.
In fact, there is not much need to repair the thermocouple. This device has a very affordable price which makes frequent replacement possible.
So, we have already figured out how the thermocouple works. It consists of two conductors connected at one or more points. This device looks like a thick metal wire with bulges at the ends. The thickenings are conductors, and the wire itself consists of chromel and aluminum.
Thermocouple working principle:
- Dissimilar metals interconnected, or rather their junction, are heated to a certain temperature;
- A voltage is formed at the cold ends of these metals;
- A measuring device is connected to the ends of the conductors, and the circuit is closed;
- Due to the voltage that has arisen, induction occurs in the solenoid valve coil;
- Due to this, the shut-off valve opens and is held open.
If we explain how we see how the thermocouple works, then the principle of its operation will be as follows: we press the solenoid valve stem, opening it manually, the igniter receives a portion of gas, from which it flares up, at this time the ends of the thermocouple located above it are heated, through half a minute this element begins to generate voltage and the valve opens, you can release the stem.
Advantages of a thermocouple for a boiler
The thermocouple is present in all gas heating equipment. It is in columns and boilers. At the same time, this element was not used in boilers before and they completely dispensed with it. Why now no gas boiler can do without this element?
The thermocouple itself is inexpensive, but the wires installed between the panel and the thermocouple are more expensive than the rest of the device.
The thermocouple gained its popularity due to the large number of advantages of its use. After all, only with the advent of this device, manufacturers were able to provide safe and high-quality electric ignition.
Advantages of using a thermocouple:
- Despite the fact that the thermocouple is a flame control sensor, it can also be a temperature tester;
- This element of the gas boiler is very simple, it does not have additional parts and complex equipment, such a device makes the thermocouple cheap;
- This part can withstand a wide range of variable temperatures;
- The accuracy of the thermocouple is at its best, which is why it can be used in such hazardous products as gas boilers and water heaters;
- Repair and installation of a thermocouple is so simple that even a simple layman can handle it.
Despite the fact that the thermocouple has a lot of advantages, it has its drawbacks. First, the relationship between the heating temperature and the increase in potential is not linear, that is, the electric potential does not increase with increasing temperature. Secondly, the limit of potential growth is rather small. These negative qualities do not affect the operation of the equipment as a whole, but when temperatures change, the device requires high-quality calibration.
Also, the advantage of a thermocouple - simplicity and reliability, is at the same time its disadvantage. You ask how? The fact is that if the thermocouple burns out, and this sometimes happens, its repair will be impossible. In this case, the thermocouple will simply have to be replaced. In addition, a gas boiler will not work without this element. However, the price of the thermocouple is quite acceptable, and its installation is quite simple.
How to test a thermocouple on a gas boiler
Unfortunately, the thermocouple fails more often than other parts of a gas boiler. In this case, all equipment simply stops working. Therefore, when a gas boiler fails, the first suspicion arises that it is the thermocouple that has burned out.
If your gas boiler is out of order, then the first step is to check the thermocouple. It is this element that most often causes the shutdown of all equipment.
Before you go to the store for a new thermocouple, you need to check whether the reason for the breakdown of the equipment is precisely in it. You can do this without calling the wizard yourself. However, in the course of work, you will have to take measurements with a multimeter, so make sure you have it in advance. You can buy it at the store, or call your friends and find it for free.
Thermocouple check:
- Disconnect the thermocouple end from the solenoid valve. To do this, they need to be untwisted.
- Remove the thermocouple from the boiler. Heat its end, which was above the boiler burner, over a candle or gas burner;
- Next, you need to wait half a minute and measure the readings at the input contact using a multimeter. If they are less than 17 millivolts, then there is a malfunction in the thermocouple.
like this in a simple way you can check if the thermocouple is the reason for stopping the operation of the gas boiler. This work is simple and does not require much time. The only problem in this case is finding a multimeter.
Thermocouple repair or replacement
In most cases, a failed thermocouple cannot be repaired. The fact is that if this device burns out, then there is nothing to repair there, so we suggest considering the process of replacing it.
In most cases, any thermocouple fits a wide variety of boilers. It's all about the prostate of its device and versatility.
Replacing the thermocouple is enough simple job. Even a person who is far from such work can cope with it. Therefore, in this case, you can do without the help of a wizard.
Steps for thermocouple stone:
- The thermocouple is installed on the gas line through a special pipe, to which the thermocouple is attached with a copper nut. To disconnect the thermocouple, this nut simply needs to be unscrewed.
- You also need to unscrew the compression screw. You will find it under the bracket.
- Now you can remove the old thermocouple.
- To install a new element, you need to tighten the nut and screw. In this case, it is necessary to check that the connection is tight. If this is not the case, then use ceramic or polymer gaskets.
As you can see, replacing a thermocouple is a very simple job. The main thing is that other parts of the boiler, for example, a separator, do not suffer during your actions.
Do-it-yourself thermocouple repair (video)
A thermocouple is a very important element of a gas boiler. And despite the fact that it partly fails, manufacturers have not yet found a better device. After all, the thermocouple has a simple structure and a low price.
Content- Device, principle of operation and main types
- Thermocouple in the gas control system (gas control)
- Connecting, testing and troubleshooting
The use of gas for heating a private house or cottage is very convenient and cost-effective. However, this type of fuel is fraught with a serious threat. If, for any reason, the burner suddenly goes out and the gas supply is not shut off in time, a leak will form and this can turn into serious trouble and endanger the lives of people in the room. In order to immediately turn off the gas if the flame suddenly goes out and a thermocouple for a gas boiler is used.
In this article, we will talk about what a thermocouple is, why it is needed and how it works, consider the main types and most common malfunctions associated with these devices, as well as a method for eliminating them.
Device, principle of operation and main types
A thermocouple is a classic thermoelectric transducer that is used to measure temperature in various fields of industry, science, medicine, as well as in automatic control and monitoring systems for gas boilers, stoves and columns.
It is arranged very simply and can be easily made independently. Two conductors of different materials are connected into a ring. One of the connection points is placed in the measurement area, and the second is connected to the measuring instrument or converter.
Photo 1: Thermocouple for gas control device
The principle of operation of a thermocouple is based on the thermoelectric effect, or as it is also called the Seebeck effect. It lies in the fact that at the junction of two conductors from different metals connected in a ring, voltage appears. If the temperature of the soldering points is the same, the potential difference is zero. But as soon as one of the junctions is placed in an area with a higher or lower temperature, a voltage appears that is different from zero and proportional to the temperature difference. The coefficient of proportionality is different for different metals and is called the thermo-EMF coefficient.
Photo 2: Design and operation of a thermocouple The main materials for the manufacture of thermocouples are noble and base metals. Most of the alloys of them have rather exotic names, which are very popular with the compilers of various crosswords and crossword puzzles. Depending on which metal pairs are used in the manufacture, thermocouples are divided into several types. Below is a table with their main types, designations and characteristics:
In automation systems for gas water heaters, stoves and boilers, thermocouples TXA from chromel-alumel (type K), THC from chromel-kopel (type L), TGK from iron and constantan (type J) are usually used. Precious metal alloy sensors are designed for high temperatures and are mainly used in foundries and other heavy industries.
Photo 3: Sakhalin gas burner for heating boilers and furnaces Some solid fuel models, such as these, can be equipped with gas burners that use thermocouples to protect against gas leaks.
Back to indexThermocouple in the gas control system (gas control)
If you have decided, you do not need to worry about what will happen if the fire suddenly goes out. However, when you use gas equipment, you need non-volatile automation that can shut off the gas supply as quickly as possible if the burner suddenly goes out. For these purposes, in modern gas boilers a gas control system is provided. How does it work?
The system consists of two main parts: a solenoid valve and a thermocouple. One end of the sensor is placed directly in the burner flame, and the other is connected to the solenoid valve, which consists of a core with a winding, a cap, a return spring, an armature and an elastic band blocking the gas supply.
Photo 4: Non-volatile gas control system for stoves and boilers The gas control works quite simply. By pressing the gas supply button, you deepen the rod inside the coil, charging the spring. According to the instructions for igniting a gas boiler, the supply valve must be held down for about a few tens of seconds. This time is necessary for the thermocouple to warm up and sufficient voltage to appear at its ends to hold the valve inside the coil.
At the moment when the burner goes out, the thermocouple begins to cool down, the voltage at the ends of the thermocouple decreases and at some point, the return force of the spring outweighs the electromagnetic force holding the stem inside and returns the valve to its original position, shutting off the gas supply. This process usually takes several tens of seconds.
One of the features of gas control is that it is completely electrically independent. In large heating complexes, such as when the power is turned off, the entire control system ceases to function. The thermocouple gas control system is completely electrically independent, and is able to function reliably without the need to connect to the mains.
The background is. A Neva 3208 gas water heater is installed in my husband's apartment, it is over 10 years old. It's no secret that manufacturers often discontinue older models, so it's difficult to buy spare parts for them. Our geyser needed to replace the thermocouple.
I called all the stores in Nizhny Tagil, related to gas equipment. They answered in the negative, or promised to call back - and did not call back. Then she turned to the ubiquitous search engines, and typed in the search bar "buy a thermocouple for a gas column Neva 3208".
The search engine returned three online stores. The cost of a thermocouple is from 190 to 250 rubles. In one online store, the minimum order amount was 500 rubles. And even buying two thermocouples would not help me get this amount. It would be necessary to put three in the basket. In another online store, for some reason, mine was not in the list of regions where delivery is carried out. The stars aligned - I made an order in the TeploYarService online store.
The store has a very easy to navigate website.
The TeploYarService company offers a list of spare parts for domestic gas boilers, stoves and columns. Here you can find the part you need for your gas equipment.
I bought a "spare part", I can not say anything about the rest. The trade name is "Arbat thermocouple for gas column NEVA 3208". Cost - 250 rubles. I didn't register on the site. Added to cart and proceeded to checkout. Cash on delivery goods are not sent, but my order amount was minimal, and there was no choice, so I decided to take a chance.
All communication with the manager took place on e-mail, which suited me perfectly. But you can also call the phone numbers listed on the site. The message about the accepted order came to the mail, the delivery cost exceeded the cost of the order - 350 rubles, so what to do ... as one joke says, "the envelope is also worth something", plus transportation costs.
I chose payment bank card Sberbank, and instead of the card number to which the money should have been transferred, they sent me a photo of the card. OK. Although copying the number would be more convenient and reliable.
The note should have included the order number. but I forgot to do it, so I wrote a message about the transfer. In response, I received "thank you, I'll try to send it today." Sent, and really, quickly, the mail ID number also came to the post office.
Russian Post worked promptly, and soon the parcel was in my post office. The thermocouple came in a standard plastic envelope, the declared value information did not match the cost of the part. A little bit.
The thermocouple was simply enclosed in a cardboard. I understand that it won’t fall out any further than the envelope, but I didn’t like this moment. Still, the shipping cost is quite high, at the rates of the Russian Post (I sometimes send parcels, I made returns to jewelry stores several times), it was possible to fix the part from all sides.
Actually, the thermocouple itself:
If it were possible to set a differentiated assessment, I would put 4.5 points. Because the online store did not reach the "5" a little. But "good" is also good. Managers are polite and pleasant in communication, they work quickly. I wish the store prosperity and all the best. Might have to ask for something else sometime.
Yaroslavl residents are lucky, they can use the "self-delivery" option.
