Vaillant boiler: malfunctions, diagnostics, error codes and causes of breakdowns

If you are the owner of a Vailant gas boiler, do not wait until something breaks to study the error codes. He who is forewarned is forearmed.

After all, a gas boiler is a complex technique; in the event of an emergency, competent actions will determine how the Vaillant boiler will operate in the future.

Malfunctions most often require a professional approach, but you can do something yourself.

Vaillant error F28: what is it?

If you look at the instructions, there is information about this error, but it is difficult to give an exact definition. The malfunction is related to the gas burner. What happened to her needs to be examined individually.

Probable reasons:

1. Gas is not supplied.
2. The valve has fallen out.
3. No grounding.
4. The electrodes are broken.
5. The electronic board is outdated.

The error is common and most often indicates a problem with the valve. This is the weak point of boilers; they have a certain operating life. If the equipment, for example, has been used for more than five years, then you should not be surprised.

Video on the topic

Gas autonomous heating systems are the most common and optimal from an ergonomic point of view today. But due to not the best operating conditions, they are often subject to various breakdowns, regardless of the country of origin and the price of the unit.

For example, a Vaillant boiler, the malfunctions of which are often associated with poor gas purification, may not last even one season, although it costs a lot of money. And this is not the fault of the manufacturers, because the equipment is designed for optimal conditions and cannot always effectively deal with problems arising due to the fault of public utilities.

Boiler inspection and maintenance

Gas boiler maintenance is recommended annually. Basically, maintenance comes down to visual inspection and preventive cleaning of the main components: heat exchangers, combustion chamber, coarse filters and the condition of the expansion tank.

The outside of the primary heat exchanger is cleaned of soot with a soft brush. Under no circumstances should you use brushes with metal bristles, because... The copper plates are treated with a special anti-corrosion coating and its damage will lead to a serious reduction in service life. Due to their design features, primary heat exchangers from the inside in most cases cannot be washed; their service life can be seriously reduced by the use of antifreeze or frequent replenishment with high-hardness tap water.

The secondary heat exchanger (DHW), due to the constant flow of water through it, is more susceptible to the formation of deposits and scale, but it can be successfully washed at regular intervals. Heat exchangers are washed with special installations (boosters) using special equipment. The process involves long-term (sometimes up to several hours) pumping of chemicals that help dissolve and wash away scale. Valiant recommends washing with regular acetic acid.

The expansion tank is designed to compensate for the thermal expansion of the heating system and is also subject to annual maintenance. It consists of measuring its pressure. The measurement must be taken on an empty boiler and, if necessary, pumped up to the static pressure of the system (approximately 1-1.2 bar). If water comes out of the control fitting, this indicates that the tank membrane is not sealed and needs to be replaced.

It is necessary to wash and clean heat exchangers in a timely manner, because dirt and scale deposits reduce thermal conductivity and flow area, which leads to a decrease in the efficiency of the boiler and overheating, and subsequently an expensive replacement.

It is recommended to set the hot water supply temperature so as not to dilute it with cold water, thereby ensuring minimal heating. The lower the temperature of the hot water, the lower the intensity of scale formation.

Coarse filters are meshes, so their maintenance is reduced to removing and rinsing under running water to the desired condition.

Over time, a gas burner can become clogged and coated with combustion products; cleaning it, as a rule, can be easily done with a soft brush and a vacuum cleaner. If there is severe contamination, it can be easily removed.

Actually a review. Reliability

Vaillant has no problems with reliability. It has been working for me for a couple of years now and has never required repair. By the way, before the start of the new heating season, do not forget to call a specialist to carry out preventive work (this winter - the second in a row since the installation - we first postponed everything until later, and then completely forgot to carry out scheduled maintenance, but there were no deviations in the operation of the boiler noticed. We are ashamed of the “German”, we will definitely call a specialist by next winter).

Not everything went as smoothly for the neighbor. But here, it seems, the installers are at fault: according to the old woman, they filled the stabilizer with water (the same as mine), and Vaillant worked without it. For the time being. This time came in the spring, in the form of a thunderstorm. It made the Turbo TecPro electronic components fly away. The case was not covered by warranty, and the part cost the grandmother 2,500 rubles. Otherwise, the boiler still works to this day without any complaints.

Features of the operating algorithm

The Turbo Tec Pro boiler operates in three alternating cycles:

• the gas is burning and the pump is running, pumping heated water;
• the gas goes out, and the pump continues to pump water for some time;
• the boiler seems to be resting (and the lower you set the temperature of the heating circuit, the longer it will “smoke” between operating cycles);
• everything went anew.

Since the boiler is a double-circuit boiler, both circuits (heating and water heating) must somehow “be friends” (communicate with heat) with each other. But something in the boiler operation algorithm seemed illogical to me:

Somewhat surprising

If, while the boiler is running to heat the batteries, you start to draw hot water, the gas will first go out, and then, after a dozen or so seconds, it will flare up again. The question is: why extinguish it?

if, when the boiler is operating to heat the house, we reduce the temperature (of the heating circuit, not the hot water), the boiler tries to use “free” energy, that is, as it considers, excess energy, to slightly heat its supply of hot water: gas (yellow light ), as mentioned above, goes out and the green indicator lights up. It would seem like a reasonable idea, but... the green light burns for literally ONE SECOND. Will you be able to heat the water circuit even a fraction of a degree in such a time?

Pleases

What’s also nice about the “German” is the possibility of additionally installing all sorts of “goodies” (for example, a two-zone temperature sensor that controls it in one of the rooms and simultaneously outside; based on the data received, it commands the boiler to heat further or pause - the device is designed to save gas) .

Of course, the engineers thought about the safety and durability of the boiler: if the water pressure in the heating circuit drops below normal, Vaillant will stop working and display an error code on its black and white LCD display (simultaneously with the red indicator). The same thing will happen if the gas pressure in the line drops, only the error number will be different. In my first winter (more precisely, already in March, at temperatures above zero), the boiler often “stopped” due to a gas error, because... handicraft in Russia is incurable - when laying a highway in a microdistrict, they were either lazy or forgot... to blow it thoroughly. Result: there was a lot of water (condensate) in the gas. In winter, it froze on the walls of the pipes, but when the heat appeared, it went into the gearbox and clogged it.

It's just infuriating

If you decide to use Vaillant TurboTec Pro for bathtub attraction, this paragraph is for you:

For some reason, Turbo Tek Pro cannot heat water “in real time” (serve as a flow-through heater). It only heats the small container of water that is located in its depths. When (quite quickly when taking a shower / filling a bath) this volume is used up, almost cold water begins to flow from the tap... AND NOW IMAGINE THAT YOU ARE STANDING UNDER THIS TAP!!! I even know what will come out of your mouth: YourBunnyWrote “№!%*? etc. After this (first... and so far last) bath/shower, you will probably think about an indirect heating boiler. It is designed to accumulate a large volume of water in advance, heating it from the heating circuit.

Summary

The Vaillant Turbo Tec Pro gas boiler is generally good and reliable. Consumes less energy than a refrigerator. Yes, there are a couple of moments in it to make fun of (like one of your careless relatives), but what you can’t take away is German reliability.

PS I have not used any other gas boilers, so I have nothing to compare with. Perhaps the above-mentioned shortcomings also occur on other models - I don’t know. I will be glad to publish your comments, remarks, clarifications.

Basic error codes (f28, f75) and their brief explanation

There are a lot of codes for various errors or malfunctions.

Let's look at the most common of them:

IMPORTANT!

In addition to error codes marked with the letter F, there are status codes marked with the letter S. They inform about the ongoing process and are not errors.

Possible malfunctions that do not happen so often

If the required error code is not in this list, this means that only a specialist can handle it.

• F0, F A breakdown occurred in the NTC sensor that controls the temperature on the flow line (F0) or return line (F1). It is necessary to check not only the sensor, but also its cable;
• F2, F3, F The NTC sensor has malfunctioned. Perhaps the plug is inserted poorly or the sensor or cable itself is broken;

• F5, F6 (Vailant Atmo). There is a problem with the operation of the sensor, which ensures the safe removal of combustion products. You need to check whether it is connected correctly, or whether the failure occurred due to a broken cable or the sensor itself;
• F10, F There is a short circuit in the flow (F10) or return (F11) temperature sensor. Check everything described above;
• F13, F The temperature in the unit has exceeded 130 degrees, and a short circuit has occurred in the hot start sensor. Check everything described above;
• F15, F16 (Vailant Atmo). A short circuit has occurred in the sensor responsible for removing combustion products. Check everything described above;
• F The boiler has overheated;
• F There is not enough water in the device, and the temperature between the flow and return lines is very different. It is worth checking the connection of sensors on both lines, the functionality of the pump and cable or board;
• F The problem is similar to the previous one - not enough coolant. Check everything the same as in step 8;
• F The device switched off due to excessively high temperature of the exhaust gases. The NTC sensor, cables and plugs must be checked;
• F The boiler reports the presence of a flame, although the valve is closed. The reason may be a problem with the flame sensor or magnetic valves;
• F32 (condensing boilers). Fan speed problems. Most likely, the problem is in itself, but you also need to check the board, cable and sensor;
• F33 (Vaillant turboTEC). The pressure switch does not close the contact half an hour after the request for heat supply;

• F The eBus voltage has dropped. Perhaps there is a short circuit in it or it is heavily overloaded;
• F No control signal is sent to the valves. You need to check the valves, cable and board;
• F Valve shutdown delay fault. Check if it is leaking gas and if the injectors are clogged;
• F The electronics unit has overheated. The reason is either external or due to a faulty unit;
• F Low water pressure. Either the problem is in the sensor itself, or there is a short circuit in it;
• F High water pressure. The reason is stated above.

Why does blood pressure drop?

The pressure drop in the boiler has a single cause - a coolant leak. If, after several attempts to increase the pressure using the supply valve, no positive results appear, you should look for a leak in the boiler itself or in the heating circuit.

Difficulty may arise if the boiler is a condensing boiler and is connected to a floor heating system.

Finding leaks in such conditions is extremely difficult. It may turn out that the fault is hidden in the discharge valve connected to the sewer system.

The optimal way to search for causes is to consistently eliminate possible causes of leaks, so that ultimately only one, the correct one, remains.

NOTE!

Certain information can be obtained if you try to determine the intensity of the leak and analyze the throughput capacity of the boiler elements involved.

Gas path diagnostics

When connecting a building to a main pipe

If we are talking about a residential building, and “blue fuel” is chosen as the main energy resource, in the house, in addition to Vaillant, there is a gas stove. After the pipes have been laid, there are no devices in the section of the circuit up to the boiler. Therefore, you can control the flow of gas without leaving the kitchen.

The check comes down to igniting all the burners on the stove at maximum mode. Flames with a characteristic shade will indicate the absence of problems with the fuel supply, and their intensity and stability will indicate the constancy of the pressure and its normal value. If the stove does not light up or does not work correctly, you need to look for a fault in the section between the main line and the place where the gas pipes are laid (the method is described below).

With autonomous gas supply

Check what

• Shut-off valve. If the Vailant boiler is taken out of service at the end of the heating season, the owner of the property, as a rule, blocks the main line and then forgets about it. Perhaps it is the gas valve that is causing the f28 Vaillant error.
• Shut-off valve. Triggered when the voltage is turned off; A “normally closed” type device is installed on the gas pipeline. It must be moved to the working position manually.
• Gearbox. Insufficient insulation of the head of a gas tank or an outdoor cabinet with a cylinder group causes icing of this device - the pipeline is blocked. Contamination of the channel is reflected in the pressure - when its value is below the response threshold of the gas valve of the Vaillant boiler, error f28 appears.
• Filling the tank. As the “blue fuel” is consumed, the pressure in the pipe also gradually drops. The most typical case of error f28. The igniter fires, the Vailant boiler starts, but the burner goes out. And so several times, as if she was missing something. Namely, normal gas flow.

Another option is the formation of an ice jam on one of the sections of the highway outside the building. But this defect must be dealt with (and eliminated) by specialists.

Ignition transformer

Failure to start the Vailant boiler is due to the lack of a spark or its insufficient power. If there are no wire defects, the Tr winding is checked with a multimeter: open – R = ∞, short circuit – R = 0. With interturn, the device will show resistance, but if the value does not correspond to the passport data, the spark is weak, insufficient to ignite the burner. Error f29 can be eliminated by replacing the transformer.

Burnt ignition electrode of Vaillant boiler

Control board

Self-repair is possible for a user with specialized education, but it will take time. Error f29 can be eliminated by replacing the Vaillant boiler assembly.

Useful tips

• With an autonomous gas supply, before the start of the cold season, it is advisable to update the thermal insulation of the outdoor cabinet with cylinders and the head of the gas tank. It is naive to hope that insulation lasts forever.
• Connect the Vailant boiler to the network via a UPS. Some errors are caused by voltage problems. The stabilizer helps, but as long as there is no break in the line. The power supply is capable of providing autonomous operation of Vailant for several hours: enough to eliminate a power line failure or problems with a backup power source. The UPS includes a stabilization circuit, a group of batteries, and a charger.
• Clean the heat exchanger housing periodically. Dust accumulation is the cause of error f29. A layer is formed through which combustion products do not completely pass through the fins of the device into the chimney. Partial flow of thermal energy is redirected inside Vailant. In addition to reducing the efficiency of the unit, the temperature under the casing increases. The result is melting of the insulation, deformation of the electronic board, periodic occurrence of errors with an emergency stop of the boiler.

Installation recommendations

The Vailant gas boiler may issue error F28 due to incorrect installation of the unit. Therefore, the installation of the device must be coordinated with the gas distribution company.

It is also necessary to correctly determine which hole in the wall the chimney will go through. Some parts of the home's structure may be too strong and thick for this type of equipment.

When connecting the boiler for the first time, it is necessary to use a voltage stabilizer. It is important to pay attention to the polarity.

In order not to encounter the fact that the Vailant boiler displays error F28, it is necessary to make the connection correctly. You need to understand that only professional specialists will be able to carry out this procedure in accordance with all requirements.

If the installation is carried out independently, then it is necessary to draw up a design for the heating system and have it certified by the relevant authorities. Do-it-yourself or poor-quality installation can cause serious problems.

Diagnostics and boiler failures

It should be noted that Vaillant equipment is one of the safest among all others. The number of settings, parameters, and checks here is significantly greater than in boilers of other brands. Boilers with displays can display status codes, diagnostics (two levels), faults and setup programs. The average user will only be interested in error codes, so everything else is mainly intended for service specialists.

The Vailant automation also stores a history of all errors, this makes it very convenient to diagnose and troubleshoot the boiler. At any time you can view the last 10 errors that occurred on the boiler (use the “info” and “-” buttons to display the list).

Next, we will consider the most common errors of Vaillant boilers and recommendations for eliminating them.

What checks are carried out before the first start-up of the boiler?

For further normal and safe operation, as well as maintaining the warranty, any equipment requires compliance with a number of conditions:

• voltage in the network according to the PUE standards and mandatory grounding of the boiler (ideally there should be no potential between zero and “ground”, Vaillant allows no more than 1.5 Volts)
• compliance of the system as a whole with the power of the installed equipment (lack of heating or hot water capacity prohibits start-up). Constant operation of the boiler at maximum power will quickly lead to failure of the unit.
• checking compliance with chimney installation standards (for atmospheric boilers, presence of draft, for coaxial chimneys, pipe extension and slope towards the street)

The installation manual also requires installing a coarse filter on the cold water supply to the boiler and on the return pipe of the heating system, as well as a gas filter.

It is better to study the commissioning process in more detail in the instructions for a specific boiler model.

The selection of the test program (airing, filling the system) is started by turning on the boiler and simultaneously holding the “+” button for 5 seconds. The selected program is activated with the “i” button. For TEC series boilers, five programs are preinstalled.

Summary

In this article we looked at the most common cases when the boiler does not turn on or ignite. No one anywhere on the Internet will definitely tell you why your boiler won’t turn on; this requires at least an external inspection. This material will help you get acquainted with possible situations in general and is written on the basis of our statistics over several years.

If there is a malfunction, you need to determine the error and read the boiler operating manual. Also, for many boiler models, error descriptions with recommendations are available on our website. Malfunctions can be simple, which the user can fix independently, or complex, requiring qualified assistance and spare parts. We strongly do not recommend performing any actions with the boiler if you do not fully understand its structure and principles of operation, disabling protective devices or changing the boiler’s operation circuit to restore its operation. If there is a malfunction, it must be eliminated! If the cause of the malfunction is not completely clear to you, it is better to call a specialist.

Useful tips

In order not to rack your brains over how to resolve error F28 in the Vailant gas boiler, you must carefully study the instructions before starting to operate the device. It is quite simple and intuitive even for a novice user. Additionally, the device is equipped with a special display, which displays all codes with the name of certain problems.

If any error occurs, you must check its number and read the annotation in the instructions. Some of the problems can be fixed on your own, but in most cases only specialized assistance may be required. To avoid troubles, before each heating season, it is recommended to call a technician who can check the boiler for leaks, as well as for proper performance.

Incorrect pressure in the unit is the most common cause of error F28 in the Vailant gas boiler. What to do in this situation? First of all, experts recommend maintaining the pressure level on the middle gray strip of the sensor. If the arrow moves into the red zone, this indicates that the indicator is decreasing very much. This can seriously affect the operation of the system.

Unit connection diagram

The connection diagram of the unit will depend on several factors, the first and most important, of course, is the type of heating system. There are three types of them:

1. Those that use natural circulation. The movement of heat is ensured by the difference in water pressure that occurs in the line due to the expansion of coolants due to increased temperature. Installation of such a line is cheaper, but you will not be able to regulate the temperature using a radiator; accordingly, the second type is used on higher-quality automation.
2. Forced circulation is carried out by special pumps, so you can freely regulate the amount of heat. Accordingly, the method is the most effective of those on the market, but the connection diagram is much more complicated and installation is more expensive. In addition, the system is completely dependent on electricity, and if it is turned off, the unit simply ceases to perform its functions.
3. Hybrid circulation. Nowadays there are practically no devices with this type of heating on the market, but such a device combines the advantages of both of the above. In the event of a power failure, the boiler freely switches to the mode of natural distillation of water through pipes.

You might be interested >> Gas-independent boilers from Conord

Accordingly, the connection diagram is available depending on the type of heating selected by the user.

Vaillant boiler error F28: how to fix

If you don’t want to understand the reasons and finances allow, of course, you can take the equipment to a service center. However, DIYers recommend not to give up and try to carry out repairs at home.

Please note that we are talking about gas equipment, so precautions must be taken. The unit must be turned off to completely protect itself.

My actions during a breakdown:

1. There is a “reset failure” button.
2. Equipment dismantling.
3. Carrying out diagnostics.
4. Boiler disassembly.

I am familiar with the structure of gas equipment and the first thing I check is the electrodes. My first thought is that the wiring is damaged. If there are exposed contacts, this is the easiest problem to fix. Take a blowtorch, everything falls into place. However, during the first inspection I did not find any problems with the wires; the electrodes are all in place (in theory, the electronic board should receive a signal).

The second point is grounding. It is checked using a tester. The most difficult thing is the valve; according to the instructions, it must withstand a certain pressure. In my case, he was clearly acting up and didn’t even know what to do. I decided to simply replace the element, error f 28 disappeared by itself.

Vaillant boiler: error F28

If we talk about this code, it can indicate several malfunctions at once. For example, the cause of this phenomenon may be a breakdown of the gearbox, which is responsible for gas pressure. The meter could also be faulty.

In some situations, the Vailant gas boiler generates error F28 when the gas is oversaturated with air. It is also necessary to monitor your blood pressure. To change these values, you must check the settings yourself.

Some users accidentally close the gas valve, which can also cause an error. In addition, the cable often breaks. The gas magnet can also fail. Additionally, you need to check the ignition transformer and make sure that there is no carbon deposits inside the system.

Most rarely, this error occurs when there is a breakdown in the control board. Therefore, regardless of whether the 24 kW Vailant boiler or another model produces error F28, it is recommended to check some components and make sure that the unit is being operated in the correct mode.

What caused the malfunction

Chimney

Error f33 is often encountered by property owners who do not adhere to the manufacturer’s recommendations for arranging the exhaust duct. Violations of the instructions have a negative impact on traction.

Causes

• Illiterate design: discrepancy between lengths, pipeline cross-section, route slope angle, number of turns.
• Violation of the tightness of the channel is the cause of error f33 of the Vaillant boiler. Check the connections, fix the flaws, and the code will disappear.
• Wrong choice of installation location for the condensate collector or its absence.
• The wind rose is not taken into account. With such a miscalculation, error f33 of the Vaillant boiler appears regularly when changing direction or gusts. The draft overturns, the unit “blows out”.
• Connection of Vaillant to the chimney existing in the house. If the channel ensured stable operation of another boiler, this does not guarantee that the same will happen with Vaillant. When calculating, the type of heating installation and power must be taken into account.
• Liquid in the pipe. A frequent case is when the chimney is removed from the building in close proximity to the roof drainage system. Moisture fills the channel, it becomes blocked, the boiler stops with fault code 33.
• Icicles on the pipe, icing. There is no traction or a sharp decrease, hence error f33.
• Frost, dust on the filter mesh of the coaxial chimney.
• Garbage in the pipe. Cobwebs, fallen leaves, small birds - in the absence of a grate, anything can get into the canal. Cleaning eliminates error f33.
• Low temperature reduces the flow rate of combustion products. Insulating the chimney solves the problem.

Advice

It is pointless to check the hood with the flame of a match, lighter, or candle. If there is a “wick” deviation, this does not mean that the draft for the Vailant boiler is sufficient. The sensor is characterized by a response threshold. Such recommendations from “experts” lead to erroneous conclusions and increase the time spent searching for the cause of the appearance of code 33. After removing the first elbow, it is easy to assess the condition of the pipe through inspection.

Fan

Its activation is indicated by the characteristic noise and rotation of the impeller. Error f33 appears even when the smoke exhauster is running, if it does not go into operation. When performing visual diagnostics, you need to make sure that the speed is normal. The slow rotation of the shaft is reflected in the traction - it drops, and the 33rd fault code is displayed.

Boiler fan vaillant

Differential relay

The device is triggered by the presence of draft, determined in the Vaillant boiler using the Pico device. This is where you need to look for the defect leading to error f33.

Pressure switch, impulse tube, Viessman boiler fan

Causes

Clean the Protherm boiler tubes

• Incorrect connection. During the process of regulation, the master or user, removing the tubes to clean the cavity, inadvertently confuses their places. A common cause of error f33.
• Polymer deformation. Differential relay, Pico device are located in the high temperature region. Constant heating of the material leads to melting of the plastic, bending, and destruction. Check and replace damaged parts.

Venturi tube

Advice

In some cases, it will be possible to restore functionality. But this measure is temporary until a new device is purchased. If the sensor failure is associated with loss of rubber rubber elasticity due to the adhesion of tiny particles to the membrane, knock the housing on a hard surface. The sludge will fall off and the f33 error problem will be resolved.

Vaillant boiler error f28 what to do?

This error can occur either randomly or require the intervention of a service technician. Error f28 occurs when unsuccessful attempts are made to ignite the gas burner.

What could be the reasons for error f28 of the Vaillant boiler:

• no gas is supplied to the burner
• low gas pressure at the gas valve outlet
• gas valve is faulty
• problem with the ignition electrodes and the flame presence electrode
• incorrect grounding of the boiler
• malfunction of the electronic board (repair of the boiler board is possible)

To begin with, you can use the Failure Reset button (flame with a cross). Perhaps the ignition failure was accidental and the boiler’s operation is returning to normal.

If error f28 appears again, we recommend calling a service technician because further checks will require special equipment and knowledge. It is not recommended to disassemble the gas valve yourself.

You can check the integrity of the wires coming from the electrodes to the control board and, during the next start-up attempt, check visually that the electric spark strikes the burner body and not somewhere else.

Service specialists check the reliability of the boiler grounding and the serviceability of the electrodes, as well as the pressure at the outlet of the gas valve. If all components are normal and there are no violations, then diagnostics of the electronic board will most likely be required.

There is no need to change the control board right away. In most cases, it can be successfully repaired. Repairs will cost significantly less.

Codes that appear most often

Errors that appear on Vailant brand boilers are most often caused by incorrect installation and adjustment work. Thus, in order to adjust the burner and gas valve, it is necessary to use a special gas analyzer. Similar work needs to be done every time F28 appears on the monitor.

The most common types of failures:

• the circulation pump is in poor condition;
• modulation mode stopped;
• the heat exchanger is clogged.

If the setting is performed incorrectly, this will negatively affect the technological mode, which is prescribed by the manufacturer in the attached documentation. All documents are included with the equipment.

Most often the following are in poor condition:

1. Gas shut-off valve.
2. Control block.
3. Igniter.
4. Engine.

If an error occurs during boiler operation, information is displayed on the control panel.

Adjustment features

Boilers from this manufacturer are easy to control. However, this does not mean that every person can cope with such a task on their own. It is best to make adjustments together, when one person turns the tap and the other monitors the position of the pressure arrow. To adjust the water or heating temperature, you can use special valves located on the control panel. In this case, how hot the water is will be displayed on the display. Thanks to this, you can increase or decrease the temperature by turning the tap to the desired position.

Also, the fact that the time has come to figure out how to eliminate error F28 in the Vailant boiler can be signaled by special light sensors on the device panel. The green light comes on when heated water is being used. A yellow indicator indicates that gas is burning. If the red LED lights up, this indicates a problem with the system. It is also worth paying attention that only water is poured into the boiler. There is no point in doing experiments.

Possible causes of failure

Most Bosch washing machines are equipped with a self-diagnosis system. If a problem is detected, the alarm code F29 appears on the display. It’s worth figuring out what this code means and what is causing the tank to fill up.

Incorrect installation of the unit

If code F29 appears on the display when you first connect the washing machine, the cause of the error is incorrect installation of the equipment.

The inlet hose must be located 50 cm above the floor and be connected correctly. If the technician installed the machine incorrectly, the system will drain water into the sewer.

Weak pressure or no pressure

Insufficient pressure in the water supply is a common reason for the lack of water in the machine. To check the pressure, you need to lower the inlet hose into a basin or sink. If the pressure is always weak, you should call a plumber to solve this problem.

If water does not flow into the tank, check the shut-off device between the water supply and the hose of the machine. Open the lock and water will fill the tank.

Faulty inlet hose

If the error appears during operation of the washing machine, check the serviceability of the inlet hose. It should not have cracks or kinks, as well as rigid fixation. In this case, free access of liquid to the system is blocked.

Filter clogged

The reason for the obstacle to filling the system with water can be a clogged filter - a mesh connecting the hose and the valve. The filter must be cleaned regularly, just like the hose itself.

Faulty door

Bosch washing machines do not take in water if the drum is not completely sealed. Make sure the door is closed tightly (you should hear a characteristic click).

Another reason is a breakdown of the hatch locking device (checked by a tester).

Commissioning sequence for Vaillant boilers

• Before filling, it is necessary to thoroughly rinse the heating system (large particles remaining after installation work can damage the actuators)
• check the condition of the automatic air vent on the circulation pump; if it is closed, unscrew it 1-2 turns
• shut-off valves on heating radiators or thermal heads must be fully open
• fill the heating system to a pressure of at least 1 bar (usually 1.3 – 1.5 bar)
• turn on the boiler and check the pressure, if necessary, recharge the system
• Be sure to check the gas deflector for leaks
• Vaillant requires filling the system with prepared water with a hardness of no more than 20 units according to the German calculation system and prohibits the addition of antifreeze or corrosion inhibitors to the system.

After the system is filled, it is necessary to carry out the P0 air removal program, in which only the pump will operate in a specially designed mode and remove excess air from the heating and domestic hot water circuit

Pressure check

This is another procedure that you can perform yourself if a problem occurs. In order to check the pressure, it is necessary to remove the unit casing. After this, you need to fold back the junction box and close the gas shut-off valve. The next step is to loosen the sealing screw located on the gas valve. After this, a digital pressure gauge is connected. Next, you can open the gas shut-off valve and put the device into operation. After this, the pressure is measured. If these manipulations do not help, then you can try other methods.

Checking and setting the minimum amount of gas

Particular care must be taken during the initial connection and commissioning of gas equipment. To check the minimum amount of gas and avoid subsequent errors, you need to perform several simple manipulations:

• turn off the boiler;
• loosen the sealing screw located on the gas valve;
• connect the pressure gauge;
• press the button with the plus symbol on the display and, while holding it, set the assignment switch “i”;
• continue to hold “+” until the value “P.0” appears on the device screen;
• press the button with the “+” sign again and wait for “P.2” to appear;
• press the “i” button and start the automatic diagnostic system, then the boiler can be switched to the minimum gas supply;
• press the “i” button and wait for a digital value from 0 to 99 to appear;
• Press the “+” or minus button several times until the pressure is set to the correct value.
• To save the changes made, to do this you need to hold down the “i” button for about 5 seconds.

In this case, the unit will automatically exit the diagnostic mode. After this, you can turn off the device, remove the pressure gauge and reinstall the sealing screw.

Checking the functioning of the boiler

And after the unit has been installed, it is also necessary to perform several manipulations to ensure that the performance of the unit is at the required level. To do this, you need to connect the device and check the gas supply lines, heating installations and other pipelines for leaks.

You also need to make sure that the burner flame indicators are in the correct position.

Error f33 vaillant how to fix and what to do?

Occurs only in turbocharged boiler models. The source of the error is the pressure switch in the exhaust pipe. The operating logic of all modern gas boilers is approximately the same. When a request for ignition is received, the control board turns on the fan (smoke exhauster), which creates a vacuum. When the required draft is achieved, the contacts of the differential relay close and thereby transmit a signal to the board to open the gas valve and ignite the burner. Accordingly, if there is no signal from the relay or it is in a closed state after the fan is turned off, the vaillant automation generates error f33.

Vaillant boiler error f33

causes:

• The fan does not work (can be checked visually)
• breakdown of the pressure switch (condensation may accumulate in the tubes, which, flowing into the sensor, renders it unusable;
• error when installing the exhaust pipe (condensation can also accumulate and flood the relay)
• clogging of coaxial pipelines, preventing normal air flow
• pitot tube clogged (accumulated dirt or insects)

You can check the operation of the relay by creating a vacuum yourself through the tube (a characteristic click should occur). It happens that the relay “sticks”, i.e. in normal condition it will be closed, which can be checked with a conventional multimeter. In this case, it will have to be replaced.

It happens that the tubes themselves or the pitot tube are damaged, for example, from exposure to high temperatures.

The slightest change in shape can affect the readings and cause error F33.

It is worth noting that this is a problem with almost all gas boilers. Some manufacturers solve this by installing a special extension (this is what BAXI did) to collect condensate, and some even make heated tubes to evaporate it.

Briefly about the main thing

When operating Vaillant boiler equipment, malfunctions sometimes occur, which the unit signals by the appearance of an error on the screen. The instructions will help you find out whether the signal indicates a minor failure or a serious breakdown. Some problems can be solved on your own. You should start by rebooting the boiler, since the cause of the message is often a system failure.

If rebooting does not help, pay attention to the external sign of the problem. They may be unusually loud noise when the boiler is operating, or low temperature of hot water. Overheating of the system causes an emergency stop; pressure surges indicate leaks. Sometimes a Vaillant gas boiler produces errors (for example, f8) due to improper operation.

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