A gas boiler is a complex household appliance, moreover, it works with an energy carrier of increased danger. Therefore, the safety of its functioning, along with reliability, is an indispensable attribute of the design. The automation of control of the wall-mounted unit is directly related to the stability of its operation in the event of possible fluctuations in the gas supply. A gas boiler pressure switch or a pressure sensor is precisely the diagnostic unit that ensures reliable operation.
The most dangerous situation in the operation of a gas boiler is its overheating in the event of a sharp decrease in water flow or a change in gas pressure. To supply a control signal to the control and regulating circuit of the system, a thermal sensor is installed in all its structures, with the help of which the most effective protection of the unit is provided. It can perform various functions.
The first option was historically used (and is still used) in flow-through gas water heaters. The adjustment method is simple and reliable enough, but it has a significant drawback - significant inertia. For water heating columns, this is not critical, since the temperature rise is to some extent restrained by the low temperatures of the water coming from the water supply, and then the relay is already triggered.
The third method for diagnosing operating conditions is used relatively rarely, since it mainly affects the quality of the evacuation of flue gases through the chimney, and cannot be installed directly in the combustion chamber. But it is often installed in the secondary working circuit as an additional diagnostic unit. The most reliable and versatile device is the pressure sensor.
The principle of operation of the gas boiler pressure switch is as follows. The sensor is equipped with a pair of contacts that are connected to two control circuits. In the operating mode, one pair of contacts is closed, in the standby mode, the other.
The electrical resistance depends on the gas pressure, and with its increase, the resistance decreases. Since an increase in pressure characterizes either a violation of traction or overheating of the coolant, this parameter determines the possibility of normal operation of the boiler and, therefore, the need for its immediate shutdown. In the work of this type of indicator, two stages are clearly distinguished.
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Gas ignition. The microprocessor of the heating system supplies operating voltage to the combustion air blower. At the same time, the flame supervision function is activated and the boiler switches to operating mode.
After the fan starts, the temperature drops, which triggers another pair of control contacts. If for some reason this did not happen, then when trying to reignite only the fan will turn on, and the flame monitoring function will not be activated. Thus, the boiler will not turn on. The start will take place only when the air pressure is within the required limits.
The user manual determines the value of the factory settings of the sensor. Typically the lower critical pressure is 0.5 bar. Consequently, with a decrease in the water pressure, the temperature of the flue gases will begin to increase. Overheating of the working contacts will cause them to immediately open with a break in the control signal, as a result, the gas supply will stop. Comparing the response of the pressure sensor with the values specified in the instructions, we can conclude that the product is working properly.
An equally important parameter for double-circuit boilers is the upper level. If it is exceeded, the pressure switch issues a command to turn off the automatic feeding of the unit, since otherwise untimely shutdown of the pump threatens to overflow the expansion tank. The upper level is controlled in the same way - the maximum possible increase in water consumption - and also compared with the values of the initial settings.
A distinction is made between gauges for overpressure, underpressure and differential pressure. Accordingly, the blocking parameters will be:
maximum value;
minimum value;
their range.
Comparing the purpose of pressure switches in different types of aggregators, you can choose a suitable sensor. They can be unlocked either manually by a button on the panel or (for fully automated boilers) by an electronic digital control system. Regardless of the design, the pressure switch must respond to changes in the pressure of both air and flue gases. The main technical characteristics are summarized in the table below.
Modern gas boilers are quite sophisticated technological equipment. With proper care and proper handling, the gas boiler will serve for a long time without any interruptions. However, even the most expensive and functional equipment has its own resource, after the exhaustion of which all sorts of malfunctions begin to appear.
DIY gas boiler repair
Knowing the main causes of malfunctions and the procedure for eliminating them, you can repair your gas boiler with your own hands. This is a very painstaking, responsible, but in most cases relatively easy job.
Contents of step-by-step instructions:
First of all, it is necessary to establish why any malfunctions may occur in the operation of gas heating boilers. A number of different factors can lead to problems.
Modern gas boilers are equipped with various automation equipment. These funds, in turn, are powered by electricity. And, despite the fact that the 21st century is already in the yard and systems for the use of alternative energy sources are being actively developed around the world, the problem of stability of power grids remains relevant for many regions, especially for remote villages and all kinds of summer cottages.
A sudden power outage or a strong surge in electricity is one of the main enemies of any modern gas boiler.
To avoid all the accompanying troubles, buy a quality stabilizer in advance. Do not spare money to buy this device - there is little sense from cheap models, so it is better to immediately allocate funds to purchase a good stabilizer from a well-known manufacturer. Be sure that in the event of a breakdown of the automation, you will spend much more money on its repair and replacement.
At home, wall-mounted models of gas boilers are often used. Such devices are simultaneously responsible for both space heating and hot water preparation.
The design of wall-hung boilers includes a flow-through heat exchanger. Low-quality hard water with various impurities is the main enemy of the heat exchanger of a gas boiler. At the same time, under the influence of low-quality water, the heat exchanger can fail in just one season.
Install special filters to prevent such damage. The best option is a complete water purification system. With it, your boiler will work as long as possible, and using purified water is much safer for health.
Any knowledgeable person will tell you: only qualified specialists should be engaged in the installation and piping of gas heating equipment.
Even the slightest mistakes at the stages of installation and connection of equipment can lead to irreversible consequences. For example, an incorrectly executed piping in the case of a cast-iron gas boiler more powerful than 50 kW will lead to the fact that the unit will simply split at low temperatures.
If you are not an experienced gas operator, entrust the boiler installation to professionals.
Therefore, if you are not an experienced gas operator, entrust the installation of the boiler to professionals - this way you will save yourself from many problems in the future.
Unfavorable weather conditions can also lead to the appearance of many different problems. In frosty winters, people turn on the heating at almost full capacity. This leads to a significant decrease in pressure in the gas pipeline system. As a result, boilers cannot fully realize their potential.
You will not be able to solve this problem on your own - you still cannot explain to your neighbors that by their actions they only aggravate the situation. As a solution to the problem, you can install an additional boiler that runs on a different fuel.
Automatic solid fuel coal-fired boiler with hopper
A modern gas boiler is a complex and potentially dangerous system. The main danger of such units is the risk of a gas explosion in the event of improper handling of the equipment or untimely elimination of various malfunctions.
Various kinds of automation are responsible for maintaining the operation of the gas boiler at an optimal level. An inexperienced user is often unable to understand its device. Therefore, it is better to immediately invite specialists to troubleshoot serious problems.
On your own, you can try to eliminate only visible damage and various contaminants that have led to the failure of the pipe, chimney and other parts of the boiler.
Typical malfunctions of gas boilers
There are a number of typical problems that you can fix yourself in most cases. Problems will also be listed, in the event of which you can only protect yourself before the arrival of a specialist.
If a distinct smell of gas or smoke appears in the room, immediately turn off the boiler and leave the room, opening it for ventilation.
Gas boiler functionality diagram
Call a professional immediately. Trying to solve the gas leak problem on your own without the necessary skills is extremely dangerous and unreasonable.
If the flame sensor or the gas supply pipe breaks down, turn off the boiler, close all gas valves and let the unit cool down completely.
Return to the area after a while to check for the smell of gas. If everything is in order with the draft, try to turn on the boiler again. If there is no thrust, immediately call a repairman.
Overheating is one of the most common problems in modern gas boilers. The reason for this may be a malfunction of the automation equipment or a clogged heat exchanger.
It is impossible to cope with the repair of automation without the appropriate knowledge.
You can also clean the heat exchanger with your own hands. The most common materials for the manufacture of heat exchangers are copper and stainless steel. There is usually no problem cleaning them, but be extremely careful anyway.
Primary heat exchanger for wall mounted gas boiler Beretta
According to the recommendations of the manufacturers, the heat exchangers must be cleaned of soot every few years (each manufacturer indicates a specific interval in the instructions for their equipment).
Primary heat exchanger (heating circuit) of the gas boiler Rinnai SMF
To clean the heat exchanger, simply remove it and clean it thoroughly with a metal brush. In the case of a copper heat exchanger, it is best to replace the brush with a metal sponge used for washing dishes.
The problematic place of fans is their bearings. If the fan of your boiler stops developing the set number of revolutions, try to eliminate the problem as soon as possible.
Fan (3311806000) for Daewoo gas boiler
To do this, remove the back of the fan, take out the stator and lubricate the bearings. Machine oil is fine for lubrication, but it is best to use a higher quality carbon compound with heat-resistant properties if possible.
Fan RLA97 (Aa10020004) for gas boiler Electrolux
Also, an interturn short circuit can lead to problems with the fan. Only a specialist can cope with the elimination of this malfunction. Return the stator for repair to replace the winding, or immediately replace the faulty unit with a new device.
Gas boiler chimney diagram
Often, excessive clogging of the coaxial chimney leads to the appearance of various malfunctions in the operation of a gas heating boiler.
Remove the chimney and thoroughly clean all of its components from soot. So you will not only return the previous level of efficiency of the unit, but also significantly increase the efficiency of the boiler.
The boiler can shut down spontaneously for several reasons. This usually happens due to a malfunction of the combustion sensor. This problem, in turn, most often leads to contamination of the gas pipe.
Draft sensor 87 ° C for Thermona boiler
Remove the branch pipe, rinse it thoroughly with water, clean it with a cotton swab and blow it off the remaining moisture. Put the pipe back in place and try to turn on the boiler. If it doesn't help, call the wizard.
No wonder they say: the best repair is prevention. Gas boilers require annual preventive maintenance, which must be carried out before the start of the heating season.
Whenever possible, maintenance should be carried out twice a year, before and after the heating season.
Check all the previously discussed boiler elements for their serviceability. Follow the preventive maintenance recommendations given by the manufacturer in the instructions specific to your boiler. Eliminate any malfunctions that arise in time, if possible.
Remember! A gas boiler is a potentially hazardous equipment. Incorrect use and untimely troubleshooting can lead to irreparable consequences. Therefore, be careful and do not engage in any repair work if you doubt your ability and correctness of action. Otherwise, follow the instructions provided.
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Gas boilers of a modern type are complex units, with the help of which residential premises are heated by heating water. They work using explosive gas, therefore, the design of such equipment requires the presence of special elements that control the operation of all mechanisms. Such control devices are called pressure switches for gas boilers.
Pressostat, monostat, smoke detector, differential pressure switch for smoke, pneumatic relay - these are all different names for the same device. An important detail controls the activity of the boiler fan, as well as the smoke removal process, protects the boiler from overheating during a sharp drop in gas pressure or at the time of a decrease in the amount of supplied water. In addition, the smoke detector allows the burner to function or, conversely, turns it off.
Visually, the pressure switch is a small flat plastic box , inside which there is a sensitive membrane and a three-contact microswitch connected to it. It is these details that control the operation of a complex heating apparatus.
The differential relay has a pair of contacts connected by two control circuits. During normal (standard) operation of the heating device, one block of contacts is closed, with a duty one - the second.
In more detail, the operation of the device can be described as follows.
The first mode is normal pressure operation. At this time, the thermostatic membrane of the controller does not change its position, and one pair of contacts closes. The boiler operates in normal mode due to the passage of current through the described circuit.
The second mode turns on when any of the system's mechanisms fails: the relay moves inside and the diaphragm bends. The first block of contacts of the smoke detector is disconnected, and the second, on the contrary, is closed. The heating equipment stops working.
The pressure switch responds to the slightest change in temperature in the combustion chamber, registers the appearance of condensate, monitors all pressure indicators in the boiler.
Finding out if everything is in order with the pressure switch at home and finding out how the device works is quite simple. To do this, you need to slowly turn the water supply tap in order to reduce the volume of fluid entering the operating device. In this case, the value of the currently received pressure will appear on the control panel.
The minimum pressure indicator (critical number) is considered to be a mark of 0.5 bar. That is, if the water pressure decreases, the temperature of the flue gases will rise, and overheating of the contacts will occur. As a result, the gas supply to the boiler will stop, the device will stop working. The values given in the instructions for the device indicate in which mode the heating device is operated.
Another significant parameter for gas boilers is the upper (maximum allowable) pressure indicator. If the permissible value is exceeded, the relay gives a command to turn off the automatic power supply of the double-circuit device. Otherwise (for example, the monostat is out of order), the expansion tank may overflow and burst.
Thus, following the readings of the pressure switch, and comparing them with the tabular data in the explanatory book for a gas boiler, one can understand whether the heating unit is working correctly or not.
The following factors are evidence that the pressure switch for a gas boiler has fallen into disrepair.
The fan is switched on silently in the monostat. The absence of an audible signal indicates that the device has experienced a malfunction and needs immediate repair or a complete replacement. Important! When the fan starts up, a click must be heard.
The boiler does not turn on, and when you try to turn it on, the device gives an error signal (most often the red indicator lights up).
A fan, also known as a smoke exhauster, is installed in gas heating equipment in order to forcibly remove smoke from the combustion chamber. A gas boiler equipped with such a system is called turbocharged. The operation of the exhaust device is monitored by a smoke pressure sensor (pressure switch). It is connected to the impeller chamber via a venturi tube.A breakdown of the gas boiler fan leads to a stoppage of the heating device and its further operation, until the malfunction of the exhaust fan is eliminated, is impossible.
It is not difficult to repair a gas boiler fan if you have identified the cause of the breakdown, found components and know how to work with a tool.
The fan consists of units:
A motor that rotates the impeller.
A turbine that creates a vacuum in the combustion chamber.
Blades for mixing the supply air.
Venturi tubes that create a differential pressure for efficient operation of the pressure switch.
Gas boiler fan device.
The exhaust fan turbine is housed in a casing made of galvanized sheet or aluminum. The motor is attached to the body with mounting bolts through vibration pads.
When 220 volts appear on the stator inductor, the armature begins to rotate the turbine and blades. Mixing of supply air and removal of flue gases is created through a coaxial pipe or a separate air duct and chimney.
The electric power of the fan depends on the heat output of the boiler, for household models, 35 - 80 watts.
Breakage is accompanied by the following symptoms:
The motor is humming, but the turbine is rotating slowly or not.
The boiler stops working in the specified mode and an error code appears on its control panel with approximately the following content: "Delay in pressure switch actuation".
The smoke exhauster may be faulty for the following reasons:
The inductor is damaged. Under the influence of high temperatures resulting from the removal of hot gases or overloading of the motor, the wire insulation melts, which leads to a turn-to-turn short circuit or to a break in the coil winding.
Turbine unbalanced. In the process of removing smoke, the fan blades are covered with soot, dust, etc., which leads to a change in the center of gravity of the wheel.
Bearings worn. The armature shaft is equipped with plain or rotary bearings. If the turbine is unbalanced, there is insufficient lubrication, the service life of these units is reduced.
There is no power supply to the exhauster. The impeller will not rotate if the control board module that supplies power to the fan is faulty.
Low mains voltage. When the electric voltage supplied to the boiler is less than 195 volts, the pressure switch can turn off the fan, since a sufficient vacuum is not generated due to the decrease in power. The underestimated supply voltage of the gas boiler does not lead to damage to the fan, but creates a malfunction effect.
Before carrying out diagnostics, it is imperative to de-energize the device being repaired and dismantle the front cover for a detailed inspection of the fan. If one of the above listed symptoms of malfunction occurs on a turbocharged boiler, you can proceed as follows:
Check the mains voltage value. Connect the voltmeter to a power outlet. If its readings are less than 195 volts, then the pressure switch turns off the fan due to a decrease in its performance. Since electrical components are powered from unstable voltage, it is advisable to connect the boiler to the electrical network through a voltage stabilizer.
Examine the inductor for an open circuit. A serviceable stator winding has a resistance of 50 - 80 ohms.
Checking the coil of the gas boiler exhaust fan.
Determine the voltage supply from the control board. On de-energized equipment, disconnect the power terminals from the smoke exhauster, connect a 250 Volt voltmeter to them and start the boiler. After turning on the circulation pump, electrical power from the control board will go to the fan, and in this case to the measuring device, which should fix about 220 volts. No reading indicates a problem with the fan control board module. The relay may be damaged.In such situations, the control module is restored or replaced with a similar one.
Checking the supply voltage of the fan of the turbocharged boiler.
Inspect the condition of the bearings. Turn on the heating or hot water supply mode and, while the turbine is rotating, carefully, using a long thin object (handle, rod, screwdriver, etc.), shake the shaft in the bearing assembly to detect play. If this method does not suit you, then disconnect the engine from the smoke exhaust chamber and apply an impact (rotate, shake, etc.) on the impeller. The bearings should be replaced when the seats are severely worn or the race is destroyed. Rolling bearings are easily interchangeable. Well, the bushings are not for sale, they need to be made by yourself, ordered from a turner, or, choosing a special clip for the inner diameter of the axle box, install a rolling bearing.
Checking the condition of the boiler fan motor bearings.
Blades are mounted on the motor shaft for mixing the supply air. When replacing the bearing located near the impeller, the blades are removed from the shaft, but it is almost impossible to reinstall them. In practice, the smoke exhaust system works stably without them.
Checking the serviceability of the gas boiler pressure switch.
Violation of the tightness of the tube with the condensate collector creates an air hindrance and the pressure switch membrane is not attracted to the microswitch. To check the integrity of the tube, you can immerse it in a container with water and, holding the side nozzles, blow air through the top nozzle. Air will escape through leaks. If there is such a defect, the tube must be replaced. In an emergency, damage can be repaired with silicone, tape or hot melt adhesive.
Information about the circulation pump Wilo MTSL 15/5 HE-2 is presented. Consider the purpose of the device, its principle of operation, the causes of the malfunction.
Possible causes and ways of eliminating overheating of the coolant in double-circuit, automatic and semi-automatic gas heating boilers are described.
This article describes five practical ways to remove icing on a coaxial duct.
The main reasons for the change in pressure in a closed heating system are listed, effective ways to stabilize the coolant pressure c.
We will analyze what to do if the gas water heater with a semi-automatic ignition system does not ignite, the principle of operation of the ignition system, the reasons.
There is a VIESSMANN VITOPEND 100 WH0A turbo boiler.
Now the box had to be removed, tk. the condensation that forms in it flows along the walls. Now, at temperatures below zero, the boiler goes into an “accident” once a week.
Local “experts” suggest supplying air directly from the kitchen. I would not like to do that, because at the same time it will be cold in the apartment.
The sensor itself (pressure switch) works at temperatures above zero. At low temperatures, it does not return to its original position (in which it should be when the fan is not running). After several blows into the tube, it starts to click normally, after which the boiler will work. It seems that grease is solidifying in the sensor.
Is there any solution to the problem (put the sensor from another boiler, replace the sensor, try to disassemble and lubricate it - it's not very clear if this can be done)?
konmix , It is necessary to bring the smoke exhaust system back to normal, and the pressure switch, if it is buggy, then only a replacement.
If there is a problem with the pressure switch (level switch), the machine may stop in the middle of the cycle, refusing to continue working. In this article we will look at the device, its importance in the operation of the washing machine. You will learn how to check and adjust the pressure switch with your own hands.
Since the work of the parts in the machine is controlled by the main module, it needs to give a signal to stop the collection of water, as well as close the inlet valve. But how does the module know that the accumulated volume is sufficient? Let's see what the purpose is, as well as how the pressure switch works in the washing machine. This element controls the amount of water collected in the MCA. Each separate mode - wash or rinse - requires a different amount of water.
Let's consider the principle of operation of a pressure switch in a washing machine. This is a rounded part with a plastic body, connected to it: a hose through which the pressure passes, and wiring. A thin membrane and a switch are located inside the relay housing. The pressure in the tank depends on the amount of water collected. Air under pressure passes through the hose, acts on the membrane, and it, bending, closes the switch. With the help of wiring, the module receives a signal to stop water intake. Such are the structure and operation of the pressure switch.
Many users do not know where the pressure switch is located in the washing machine. Some people think that it should be located inside the tank. In fact, the device is located at the top of the CM body, near the side wall.
How can the user guess about the breakdown of the level switch without disassembling the washing machine? The main signs are:
SM with a self-diagnosis system, detecting a malfunction, immediately display an error code on the display. The user reads and decrypts the code, which makes it possible to understand which part is out of order.
The washing process starts, but you see that there is no water in the drum. In this case, the machine turns on the heating element, which can lead to a fire and a malfunction of the heater.
The amount of water collected exceeds the permissible level. A continuous supply of water is possible. There are situations when the level does not reach the minimum value.
Poorly wrung out laundry. In the event of a malfunction of the pressure switch, it is possible that the water does not completely leave the tank, therefore the spinning is of poor quality.
Such malfunctions can also indicate a breakdown of other components, such as the control module or the inlet valve. It is even possible that the system is incorrectly connected to the sewer. Therefore, to be sure, it is important to know how to check the relay (pressure switch) in the washing machine.
Even a beginner can handle this kind of work, so do the following:
Stick to safety precautions. Disconnect your AGR from the mains by unplugging the plug.
Turn on the inlet valve, which is responsible for the water supply.
To check the water level sensor, remove the top panel in the washing machine.
After unscrewing the screws at the back, slide the cover forward. Be careful when doing this, as the edges may be sharp.
Putting the panel aside, find the device.
Prepare a tube with a diameter equal to the pressure switch connection. Remove the pressure hose by releasing the clamp. Place the tube on the fitting and blow lightly. If the sensor is working properly, then the contacts will work, and you will hear one or three clicks.
Check the device for damage. Check its hose for blockage. If it is clogged, clean the hole with water from the tap.
When you have made sure that everything is outwardly in order, the last method of verification remains - a multimeter. Set the tester to resistance mode and connect the tester probes to the relay contacts. When the contacts are activated, the values should change. If they remain at the same level, then the sensor is faulty. To find out exactly which pins to connect the tester to, you will need an electrical diagram of the instrument.
Sometimes, instead of replacing a part, you can make an adjustment or tune the pressure switch in your washing machine. How to proceed:
It is important to know how much water a given model of washing machine requires for each program. Based on their number, there are from one to three screws on the sensor.
In accordance with the required amount of water in the mode, you need to tighten the screws.
Knowing how to set up and adjust the pressure switch, you don't have to buy a new part. But calculating the correct tuning coordinates is rather difficult, since such work is carried out by specialists at the factory. If you decide to replace the relay, read the next paragraph.
First, buy a new appliance. You can take your sensor and go to the store with it, but usually, to buy a suitable part, it is enough to tell the seller the model of the car. If you did not completely remove the relay when checking - do this:
Disconnect all wires (take pictures or mark connections).
Remove the bolts that secure the device to the body.
How to connect a pressure switch? Repeat all steps in reverse order:
Screw it in place with the bolts.
Then connect the hose by securing the hose clamp.
Connect the wiring according to the markings.
Fine! The work was done successfully - you can launch your CM and check its work. A video on the topic will help you:
Video (click to play).
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