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.

Decoding

Error f61 indicates incorrect operation (failure) of the gas valve of the Vailant boiler: violation of valve control. Replacing a unit does not always lead to a positive result - the code is triggered by a number of reasons, and the problem is not necessarily in the main battery: it is more related to the Vaillant electronics. Below is a recommended algorithm of actions that reduces troubleshooting time.

What to do

Step 1

Restart. Error f61, like others, is often caused by instability of the parameters of the power supply network of the Vailant boiler. Press the button and hold for 5 seconds: Reset, “Network”, “On” (depending on the type of unit). Often this action clears the fault code.

Button for resetting error F61 on the control panel of atmoTEC pro, turboTEC pro Vaillant boilers

Connect the Vaillant boiler via a voltage stabilizer

Step 2

Assessing the condition of signal lines. Loss of gas valve control, error f61, may be the result of unreliable contacts, broken wires, or short circuits. Remove the casing from the Vailant boiler, inspect the cable connecting the main battery to the electronic board

Particular attention to the connectors: condensation and oxides cause a break in the control circuit. Detected defects are eliminated independently - the services of a specialist are not needed

Step 3

GK testing. Depending on the type of Vailant boiler, gas fittings differ in design features: number of valves, control voltage values, settings for the type of fuel (main, liquefied). But the user can identify a number of problems when searching for the cause of error f61 on his own.

Replacing the gas valve in a Vaillant boiler

Check what

• Windings of coils, a stepper motor that controls the second valve. Testing for serviceability involves measuring resistance. In the event of a short circuit, the multimeter will show R = 0, and an open circuit - ∞. Error f61 is also caused by an interturn short circuit, but to diagnose it you need a special device and accurate data on the characteristics of the winding (they are not in the service manual).
• A gas tube connected to the gas inlet port. “Garbage” in the cavity (according to experience with Vailant boilers) is a common cause of errors, and not only f61. Sludge is applied into it from the main line, passing through the filter grid. Clean it and code 61 will disappear.
• Internal channels of Vaillant gas fittings. The method for eliminating error f61 is similar - blow it out, remove any trapped fractions from the assembly (graphite chips are often found).

Step 4

Inspection of the electronic board. The ECU controls the operation of the gas valve, and the loss of “visibility” between the components of the Vailant boiler, changes in the voltage values ​​supplied to the main valve coils and the engine are the causes of error f61. Diagnostics are carried out in a workshop, on a bench: different operating modes of the heating unit, emergency situations are simulated, and the response of protection circuits is assessed. To eliminate error f61, you need to inspect the board yourself.

Check the Vaillant boiler control board

What to pay attention to

• Mechanical damage: cracks, splits of panels, parts bodies.
• Dark spots, melted areas of the circuit.
• Breaks, peeling of tracks.
• Connector condition. Moisture and oxides in the boiler board connectors are the cause of error f61.
• Condensate. Drops of water on the surface lead to short circuits and Vailant fault codes.
• Dust. When saturated with vapor, it becomes a conductive layer. Remove it and error f61 will disappear.
• Relays that close circuits through which control voltages are supplied to the gas valve and stepper motor. There are several of them, and you can “calculate” what you need using the tracks. Error f61 is often associated with burning of the contact group. It can be removed by replacing the corresponding relay. But this advice is for those who have experience in repairing electronic devices.

If you cannot resolve the problem on your own, contact an authorized service organization. When submitting an application, indicate the type of Vailant boiler (inscription on the marking plate), year of manufacture. A more thorough diagnosis of the heating unit is the job of a professional.

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

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.

Advantages and disadvantages

The advantages of products from the German brand include the following:

• The presence of a modulating burner allows you to effectively regulate the power of the device.
• Closed firebox.
• Possibility of automatic transition to maintenance of the hot water supply system without the participation of the owner.
• The primary heat exchanger has undergone major design changes. This made it possible to increase the efficiency to 91 percent.
• The copper heat exchanger is additionally protected by the proprietary “Suplar” coating.
• Availability of a plate flow heat exchanger.
• The equipment independently monitors the status of all components in real time, performs an automatic emergency stop when critical faults are detected, and records error codes in the internal memory.
• The circulation pump supports operation in several modes.
• Integrated expansion tank on some models.

No equipment is without drawbacks, and the Vaillant gas boiler is no exception. Here they are as follows:

The need to connect to the mains. If there is no power supply, the equipment will automatically stop

To get rid of this problem, it is enough to purchase an uninterruptible power supply, first paying attention to its power. High prices. High quality workmanship, the use of durable wear-resistant materials and modern technical solutions could not but affect the cost

On the other hand, this is more of a side effect than a disadvantage. After all, the technological effectiveness of the equipment has a positive effect on the level of energy consumption, thanks to which the user saves additional money.

Prevention

Like any other equipment, the boiler requires timely prevention.

Cleaning the boiler

Cleaning of soot from the boiler is carried out with a soft brush from the outside. The use of harsh cleaning is unacceptable, since the boiler plates are made of copper, with an anti-corrosion coating that cannot be removed. The disadvantage of the heat exchanger design is that it cannot be internally washed, and the use of antifreeze or feeding the circuit with hard water shortens the service life of the unit.

Fighting deposits and scale

The problem of deposits is even more important when operating secondary hot water boilers, due to the constant circulation of hard water through its circuit. This means that it becomes even more clogged with deposits and scale. The manufacturer took care of this situation and created conditions for periodic washing of the heating surfaces of the DHW circuit. This can be done using a booster with the addition of special agents to the circulation coolant.

Next, the solution is run for several hours, dissolving and washing away the scale.

Note! In addition, it is recommended to maintain a low temperature for hot water supply, which does not require dilution with cold water. In this case, the intensity of scale formation, which begins at 60 °C, will be practically reduced to zero

Expansion tank maintenance

Expansion tanks are subject to annual maintenance. To do this, the boiler is filled with water to the operating level in the system of 1–1.2 bar. If water appears from the control output of the expander, then the tightness of the tank membrane is broken and it will need to be replaced.

Burner and filters

The filters on the gas line are made in the form of a mesh; for maintenance they are removed and washed with water. The gas burner also becomes clogged with combustion products over time; it should be cleaned with a soft bristle brush and a vacuum cleaner.

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 ensure complete safety.

My actions during a breakdown:

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.

Is it possible to carry out repairs yourself?

Current regulations prohibit self-repair of gas equipment. This point must be taken into account when starting restoration measures. However, there are many ambiguities in this issue - there are other components in the boiler design that are not directly related to gas equipment.

If the secondary heat exchanger or boost fan fails, the gas supply system will not be affected in any way. To solve such problems, you need to call a technician from the service center. He has all the necessary approvals and permits; gas service inspectors will not have any questions.

Another issue to consider is the validity of the warranty agreement. The conditions are quite strict - installation and initial start-up must be carried out by employees of the warranty workshop (service center), routine repairs or maintenance of the boiler must also be carried out by specialists.

Independent intervention in the boiler design is regarded as termination of the warranty agreement at the user’s initiative, and you will no longer have to count on free repairs. Even replacing the plug on the power cord can be considered such an intervention, therefore, in any situation, it is recommended to immediately call a service technician.

If you repair it yourself, the boiler will be removed from the warranty.

If there is no way to contact specialists, you have to act at your own peril and risk. When purchasing a boiler, you must immediately find out where the nearest service center is located and whether there is a possibility of quickly solving possible problems.

If the warranty workshop is located too far away and a technician does not come to your home, it makes no sense to conclude a warranty agreement.

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.

F28: causes of occurrence, corrective actions

• gas sensor malfunction;
• breakdown of the gas pressure switch;
• airing of the gas pipeline;
• low pressure in the gas line;
• breakdown of fittings in the fuel supply unit;
• incorrect feed setting;
• failure of the ignition system – the ignition cable, transformer, plug are damaged;
• improper grounding;
• carbon deposits on the sensor;
• failure of the electronic board, other problems in the electronic unit;
• problems with - low voltage, surges;
• stabilizer fault ();
• fire hydrant activation.

Initially, you should check the position of the gas tap - perhaps you forgot to open it. If open, adjust the settings, check electrical contacts and grounding, clean the gas valve. When error F28 of the Vaillant boiler is associated with a board failure, a replacement is performed by a master.

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.

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.

The Vaillant boiler simply does not turn on

If the boiler display does not light up, and you are absolutely sure that it is reliably connected to the power supply, then most likely the board has failed. Unfortunately, the self-diagnosis program does not record internal errors in the operation of the board, and if damaged, the boiler will simply go out. Quite often, these damages can be seen visually when inspecting the board.

We have everything you need to restore the boards of TEC and MAX series boilers. Here is an example of repairing one such case (the power module on the board burned out):

The repair was completed within a day and the payment was handed over to the satisfied customer.

Vaillant is a high-quality and reliable technology, but electronic breakdowns still happen sometimes. The boiler circuit board is one of its most expensive elements, so by contacting us, clients save an impressive amount of money

We have been doing repairs for a long time and all spare parts are always in stock, and repairs take a minimum of time, which is especially important when a breakdown occurs during the heating season

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.

Each Vailant boiler has a diagnostic system that is part of the electronic unit. Information about the state of the unit is displayed on the LCD display in the form of a code (including about past errors).

Before a specialist arrives, you can evaluate the performance of the device yourself:

• Check all inlet and outlet connections for leaks (this includes outlets for carbon monoxide, condensate and domestic hot water).
• Check: there are no contaminants in the reduced pressure chamber.
• Check all electrical connections: whether the connectors and plugs are tight.
• Check the condensate drain and siphon for the presence of salt and limestone deposits. If necessary, clean.

Inspect the gas burner - it most often becomes clogged with carbon deposits. The inner walls of working chambers and chimneys also need to be cleaned. There is not a lot of soot in gas equipment, so the user will not have any major difficulties.

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.

Decoding the main error codes

All faults are displayed on the automation display in the form of encrypted alphanumeric designations. Vaillant boiler error codes can be found in the list below:

• 1. Error f20 on a Vaillant boiler is quite rare and indicates overheating of the equipment. This may be a consequence of the heat exchanger being clogged with various debris, as a result of which the coolant is not able to circulate fully and is heated to a critical temperature.
• 2. Error f22 is much more common. It means insufficient water in the system or its complete absence.
• 3. Error f28 of the Vaillant boiler - the electronic board burned out. This can happen as a result of a sudden voltage surge, which is why a stabilizer is needed.
• 4. Error f29 of the Vaillant gas boiler - the gas burner does not light up. After three unsuccessful ignition attempts, the boiler automatically turns off. There can be quite a few reasons, from insufficient gas pressure to a stuck valve or clogging of the holes with various debris. You will have to carry out diagnostics yourself, since automation only gives a general idea of ​​the problem.
• 5. Vaillant boiler error f36 - release of gaseous combustion products into the room. It may occur as a result of a leak in the pipeline or insufficient draft in the chimney. The solution is described above.
• 6. Error f75 on the Vaillant boiler means a lack of water pressure in the pipeline. The solution method is described a few paragraphs above.

A list of other errors with decoding can be read in the instructions that come with each model.

Expert advice

There are some expert tips to consider. In particular, a number of tips relate to prevention and initial use of the boiler

Recommendations:

• the model must meet the needs of the heating system;
• connection must be made strictly according to the instructions;
• any small deviations from the operating cycle should be checked immediately;
• Before the first operational start, diagnostics must be carried out;
• Equipment installation is carried out by professionals; otherwise, problems may occur during the first operating cycles.

Most users have questions during operation that only specialists can answer. Also, for every question there is an answer that allows you to solve the problem. Adviсe:

1. If there is no response to turning on the water and a set of sounds that come from the equipment itself, it is worth checking the gas supply line, as well as the gas meter.
2. When pressure jumps occur due to the expansion tank, you can simply pump it up.
3. If the pressure sensor does not work correctly, error F75 appears. To eliminate this, you can simply press the supply tap.
4. When switching off the equipment and supplying either hot or cold water, it is worth setting the minimum pressure.
5. If there are delays in switching the boiler from one mode to another and sounds that resemble gurgling, it is necessary to pump out excess air.
6. In addition to water, you can only use a coolant specially selected for the boiler. There should be no other liquids.
7. When the equipment stops completely and the panel goes dark, you need to check the fuses.
8. If the flame icon flashes and does not turn on, you need to clean the filters and check the sensors.
9. If there is good pressure of cold water, but hot water flows poorly, then you will need to check and replace the heat exchanger.

It is worth considering one more nuance. The factory settings set the maximum value (not always, but often). If you have a smaller area, it is worth reducing the power. This procedure must be carried out after connection during the first diagnosis.

Different error codes may appear on the display, but the problem can be complex. An error is displayed that prevents the equipment from entering operating mode.

Once deficiencies are identified, they must be eliminated. Next, a full inspection of the equipment and configuration is carried out. After this, diagnostics are launched, which should check all modes and capabilities of the boiler.

Only after all these procedures can the equipment be put into operation.

It is also important to carry out any necessary cleaning after repairs or troubleshooting.

There is an important nuance. If the boiler is not regularly maintained, problems may arise with the filters and the chimney. That is why the maintenance procedure involves not only changing parts, but also completely putting the equipment in order.

Most often, all problems during operation are displayed on the display. These signs are what you need to navigate first.

Vaillant boiler error f75

Unlike other boilers, the vaillant self-diagnosis system checks whether the circulation pump is running. Since the pressure sensor is capable of quantitatively recording its change, the moment the circulation pump starts, the program checks for the presence of a pressure surge of 50 mbar for 20 seconds. The circulation pump is designed to pump coolant through the system, but at the moment of start-up it briefly creates a slight excess pressure. The absence of such a jump can be regarded as a malfunction of the circulation pump, and in order to prevent further overheating of the system and improper operation of the boiler, the automation blocks operation with error F75.

In fact, error F 75 can also be caused by side effects, for example, clogged sensor, air in the heating system, borderline pressure level in the circuit (low, but within the acceptable limit). If the sensor itself is faulty, status codes F73 and F74 are provided (when the voltage at the sensor is too low or too high).

The boilers are also equipped with analog pressure gauges, so for diagnostics, the sensor readings can be compared with the readings on a mechanical pressure gauge. The accuracy of a mechanical pressure gauge is about 0.2 bar.

Setup and management

Handling Vaillant boilers involves competently transferring them from one mode to another. The question often arises of how to properly turn off the heating system for the summer so as not to pay extra for gas and not overheat the house. The solution to the problem is to close the heating circuit for a short stroke, using a tap and jumpers.

If the equipment is made according to a scheme with artificial circulation, everything will be even simpler: you should disconnect the circulation pump from the scheme and seal the boiler inlet pipe. Trying to solve the problem by installing additional speakers is impractical and not very economical

It is important to remember that you will have to ensure a stable temperature by normalizing the flow of hot liquid. It is necessary to pump up the expansion tank if the pressure level continuously decreases and increases, changes unpredictably

A steady drop in pressure in the system cannot be easily eliminated; it is imperative to find the place where the coolant is leaking and eliminate the cause of the problem. The search for defects should be carried out on radiator plugs, connecting lines and where fittings and pipes are soldered.

If pumping the tank does not produce results or they last too short a time, you need to inspect the tank. Often its outer shell depressurizes and allows air to pass through. But even more often the performance of the spool valves is disrupted, which also begins to leak.

The pumping of the tank itself is carried out in the following stages:

• turn off the boiler, supply and return valves;
• open the drain fitting until it is completely drained;
• connect the pump unit via a spool, under no circumstances blocking the fitting.

Any type of pump is useful for the job; You can take a car gauge and a pressure gauge from the car too. The air pump is pumped until water flows out of the outlet fitting. Next, release the air and repeat its introduction, continuously monitoring the pressure gauge readings. It should show 1.1–1.3 bar; more precise information is provided in the technical documentation. Now you can close the pouring fitting, open all the previously closed taps, feed the boiler in the normal way to 1.2–1.5 bar, and then start warming up.

It is especially important to monitor internal pressure if the house or other structure is visited only periodically. It is no secret that the stability of power supply is now far from ideal.

And if the power stops, the boiler stops working, so the pressure inside the tank can drop due to cooling below what is required for the boiler to operate. Even after the power supply is restored, the boiler cannot warm up the house, because soon the uncontrolled house presents a sad sight - pipes and radiators torn from ice everywhere. Therefore, the pressure in the expansion tank must be constantly monitored. No less bad is the situation in which the pressure level continuously increases. Of course, a well-chosen and correctly installed safety valve corrects the matter to some extent, but it is better not to rely on it, since this is still more of an emergency measure. It is always worth remembering that pressure control deserves increased attention.

Sources

• https://boilervdom.ru/kotly/kody-oshibok/kody-oshibok-gazovogo-kotla-vajlant-oboznachenie-znachkov-i-ustranenie-neispravnostej.html
• https://kody-oshibok.ru/gazovye-kotly/kotel-vaylant-oshibka-f28.html
• https://FB.ru/article/368708/kotel-vaylant-oshibka-f-vozmojnyie-neispravnosti-i-sposobyi-resheniya
• https://www.tproekt.com/kak-ispravit-oshibki-na-kotlah-vaylant-vidy-neispravnostey/
• https://remont-system.ru/kotly/rasshifrovka-kodov-oshibok-v-otopitelnyh-kotlah-vaylant
• https://sanwayopt.ru/polezno-znat-kazhdomu/328-oshibki-kotlov-vailant
• https://stroy-podskazka.ru/otoplenie/kotly/vaillant-neispravnosti/

The boiler does not work in DHW or heating mode

And finally, situations when the boiler does not operate in a particular mode. They happen much less frequently compared to others. In this case, it is likely that the boiler will need to be diagnosed by a specialist. The process of ignition and operation of the boiler in different modes is virtually the same, with the exception that different modes may have different power. In hot water preparation mode, the boiler power is usually full, but in heating mode it can be minimal. You can read about problems in the operation of the DHW mode in a separate article.

Error f75 vaillant solutions

Since the causes of the malfunction may be insufficient pressure in the system or air, the system should be energized and the deaeration program should be started (control program P.0).

The error is reset with the “Reset” reset button (crossed out flame), or by turning the boiler off and on.

Another reason could be the expansion tank; if it is connected to the supply line, the membrane can dampen vibrations. Also, to eliminate its influence, it should be serviced - check the pressure of the air chamber of the expansion tank and, if necessary, pump it up. Maintenance of the expansion tank must be carried out after draining the water from the boiler.

If simple steps do not help, you will most likely have to remove and inspect the circulation pump. If during the inspection there is significant wear, scale deposits and dirt, it will most likely have to be replaced.

Another reason may be an automatic bypass (a device that serves to protect the pump in the event of an increase in the hydraulic resistance of the heating system). It has a spring-loaded valve, which in case of sticking (dirt or scale gets in) remains in the slightly open position.

Perhaps we have considered all the possible causes of error F75 and options for eliminating it. Other non-standard cases must be considered primarily in the context of the prerequisites for their occurrence. What a circulation pump is, how its maintenance and repair is carried out can be seen in the video below.

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.

Decoding

Error F27 informs about a false flame. The electronic board records the combustion process after sending a command to the valve to block the channel. Knowing the composition of the control circuit, it is easy to outline the circle of “suspects”: ionization sensor, gas valve, control unit of the Vaillant boiler.

Button to reset error F37 for boilers

The “behavior” of electronics is often unpredictable. Therefore, for a number of codes from the fault table, the reasons are similar. When troubleshooting error f27 Vaillant, it is recommended to follow the following algorithm.

First steps

Parasitic (induced, extraneous, false) signals are formed when the electronics of the Vailant boiler malfunction.

Restart the heating unit. If error f27 Vaillant is the result of a power surge, it will be removed.

Button to reset error F27 on the control panel of atmoTEC pro, turboTEC pro Vaillant boilers

Check Uc value

. For stable operation, Vaillant needs to be provided with ~230. Imported equipment reacts to deviations in voltage parameters (f, U), for this reason it often produces errors.

For owners of facilities where such situations are not uncommon (power line breaks, problems at a substation), the optimal solution is a UPS. The units are available in different configurations (with built-in batteries or external ones) and are capable of ensuring stable operation of the boiler on batteries for a long time.

Assess the reliability of grounding. Checking the circuit by inspection will not give a real picture. It is easy to verify the quality of the grounding of the Vailant boiler by checking the presence of potential on the metal of the heating unit with an indicator screwdriver - the glow will indicate the cause of error f27.

The problem with stray currents and false codes is solved by installing a dielectric coupling on the gas main in front of the Vaillant.

Connecting a dialectical coupling

First steps

Press button number 8 on the Vaillant boiler control panel

This algorithm of actions saves time in troubleshooting problems with heating equipment. A negative result is a reason to look for the reason for the shutdown of the Vailant boiler.

On a note! The instructions for gas equipment contain scant information on faults. The manufacturer, taking into account the complexity of the devices and their danger in terms of ignition (explosion), does not rely on repairs by the user - only a certified technician. A number of Vailant boiler errors are caused by identical factors.

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.

Repeated breakdown

The music didn’t play for long; my favorite Vaillant gas boiler broke down again. At first I got error f33 and again f28, which means a problem with the gas burner. Since the Vailant display was acting up, naturally the fault was on the control board. However, one should not rush to conclusions. Like last time, we act according to a clear plan:

1. Disabling equipment.
2. Removing a gas boiler.
3. Carrying out diagnostics.
4. Analysis of the design.
5. Checking elements.

Since I had previously inspected the unit, I decided to check all the main components. I was interested in the condition of the tap, sensors, and pump. I didn’t want to disassemble the unit often, so I thought about how to fix all the problems at once. In a Vaillant gas boiler, some elements are hidden, so it is difficult to get to them without damaging another element.

We are talking about the control board. It is located at the bottom of the structure, and to get there you will have to tinker with the bolts, in my case everything looks flimsy. Finally, the Valiant boiler is open and you can look around. The control board is a regular element, the same as in a computer. When disassembling a gas boiler, it is recommended not to touch the contacts and connecting elements with your fingers again, since greasy stains remain on them. All this can affect the operation of the automation.

Eliminating the error begins with cleaning the contacts. As you know, there are tracks on the control board, and they can be easily cleaned with ordinary office grout. As for the sensors, I just removed the dust from them. Upon inspection, I noticed that the three-way valve was loose and could possibly fail in the near future. This element is located in the upper part of the structure and is responsible for shutting off the gas.

In the store I picked up a similar three-way product, the most interesting thing was with the control board. Finding a similar variation is problematic, fortunately, the exact product code is indicated on it, so I was able to order it online.

Error F28 may also appear due to a gearbox malfunction. The element is responsible for gas pressure and is connected to the meter. When I had suspicions about the gearbox, I initially carried out diagnostics; it was necessary to check the settings. First of all, turn off the gas valve

You need to pay attention to the display. If the error code disappears, it means the element needs to be replaced. It happens that everything is fine with the magnet, but the ignition transformer suffers

Soot often accumulates on it and the gas boiler refuses to work. Checking the pressure is not so easy, since it requires removing the casing. Having reached the distribution box, close the shut-off valve. Inside there are several sealing screws that are fixed to the gas fittings. It is only necessary to loosen them a little; the structure is not as strong as it might seem at first glance

It happens that everything is fine with the magnet, but the ignition transformer suffers. Soot often accumulates on it and the gas boiler refuses to work. Checking the pressure is not so easy, since it requires removing the casing. Having reached the distribution box, close the shut-off valve. Inside there are several sealing screws that are fixed to the gas fittings. They only need to be loosened a little; the structure is not as strong as it might seem at first glance.

A digital tonometer is used to check blood pressure. In the instructions you will find exact indicators of normal pressure depending on the modification.

The most common malfunctions and their causes

Despite true German quality, like any other equipment, Vailant boilers are subject to various types of failures. If this or that problem does arise, the device informs the owner about it by displaying an alphanumeric code on the LCD display, including a red light, as mentioned above. Each error has its own code.

If you study thematic forums where boiler owners discuss their malfunctions, the most popular queries are:

• error with code F22, indicating the absence of water in the device or its shortage. It is worth checking whether the pump is jammed, whether the pump cables are securely connected to the water pressure sensor, look at the sensor itself or at the power of the pump. Possible still weak water circulation;
• error with code F28, in which the unit does not start at all. The reasons may be different: the zero and phase are incorrectly connected, the gas is oversaturated with air, the gas pressure level is too low, the control board is broken, the boiler is not properly grounded, a cable break or an error in connecting to the gas pipeline. Some problems can be solved by yourself by looking at the instruction manual. For example, check whether the gas tap is open or change the gas pressure in the boiler settings to 5 mbar;

Error F28 on the boiler display

• error with code F29, in which the burner flame constantly goes out, and new attempts to ignite are unsuccessful. The reasons may be: the gas boiler is not grounded correctly, gas supply failures in the gas system itself, problems with the ignition transformer or gas valve. To eliminate this problem, it is worth checking the gas pressure; it may drop too low or see if there is enough air for normal combustion of the fuel;
• error with code F36 (Vailant Atmo), in which combustion products come out. This problem may occur due to poor ventilation in the room or poor draft in the chimney, or the temperature in the room is too high. You should also check whether there is sufficient space between the boiler and the wall;
• error with code F75, in which the boiler pump works, but the pressure does not rise. There may also be several reasons: breakdown of the pump or water pressure sensor, air getting into the heating system, incorrect connection of the expansion tank or insufficient water pressure. To fix the problem, you can try cleaning the water pressure sensor or you will have to purchase more powerful components.

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.