vailant error F75 how to fix

In this article we will look at the Vaillant TEC series boiler.
These are modern boilers of the premium segment of the famous German brand. The model range is represented by boilers with a power from 20 to 36 kW, single-circuit and combined. Depending on the configuration, the TEC series is available in two modifications: Plus and Pro. Vaillant Pro is a cheaper model, Vaillant Plus has a hot start function in hot water preparation mode, a larger secondary heat exchanger, a larger expansion tank (10 liters), a more informative LCD display and a circulation pump with automatic speed control.

The operation of any gas boiler is permissible only if there is a working fluid in the system - coolant. By the way, Vaillant prohibits the use of antifreeze or corrosion inhibitors. Therefore, prepared water should be used as a coolant.

The presence of the required filling level of the heating system is monitored by a pressure sensor. Vaillant is a fairly technologically advanced boiler, therefore, it uses a pressure sensor that has the ability to measure its digital value. In many other boilers, the pressure in the system is controlled by pressure switches based on microswitches and a conventional mechanical pressure gauge.

The principle of operation of the Vaillant sensor is as follows: in the housing there is a spring-loaded magnet and a Hall sensor. Through the membrane, the coolant pressure in the pipeline acts on the spring and moves the magnet, thereby changing its position relative to the Hall sensor. Depending on the degree of displacement, the voltage value changes on the contacts, which are fixed by the control board and displays a numerical value on the screen to the user, and also controls the permissible value.

That is, the actual pressure value in the system is constantly monitored by the control unit.

The normal pressure in Vaillant TEC series boilers is considered to be in the range from 0.7 to 2.8 bar. When filling the system, it is recommended to ensure a value of at least 1 bar.

If the pressure value recorded by the sensor differs from the normal range, this is considered a malfunction and the diagnostic system will generate an error.

Error interpretation

There is some confusion in the Vaillant manufacturer's instructions and its interpretation. Regarding error f75, it is said that its causes may be a faulty pressure sensor or circulation pump. At the same time, the same table shows codes f73 and f74. The first indicates a problem in the signal circuit of the flow switch (short circuit, broken wire, poor contact), the second indicates a breakdown of the sensor itself.

The peculiarity of the Vaillant electronic circuit is that it not only controls the operation of the pump, but also the moment it reaches mode. This is how German units differ from boilers of other brands. If within 20 seconds after start-up there is no pressure jump in the system by 50 bar (that is, normal fluid circulation), the automation regards this as a malfunction of the pumping device and issues an error f75, which blocks the Vaillant boiler.

First steps

Gas boiler Vailant: operating instructions

At the same time, double-circuit boilers do not operate in heating and water heating modes. By default they work for heating. But when the hot water tap opens, the boiler switches to heating mode. It is worth knowing that water is heated in limited quantities - for domestic needs. The boiler switches to heating mode automatically after the hot water tap is closed.

Experts strongly do not recommend installing a double-circuit wall-mounted gas boiler Vailant yourself. Errors in installation will lead to the fact that it will not meet your expectations. Most of the complaints made by users are based on improper operation and errors during installation. Problems can occur due to poor quality of gas and energy supply, which is not uncommon in our country.

Boiler Vailant error f75

Vaillant Group is an international concern producing climate control equipment, with its head office in Germany. The company has been operating since 1874 and has representative offices in 60 countries, including Russia.

Vailant products are energy efficient and environmentally friendly. The consumer is offered a wide range of high-quality and reliable installations for heating and water treatment. In addition to traditional heating equipment, the company's engineers are developing solutions for using solar energy and heat in household appliances.

Causes of error f75 Vaillant

Bypass valve

Its task is to protect the circulation pump mechanism from powerful hydraulic shocks. The valve has a spring, and in case of contamination it does not completely close the channel (half-open position). When the pump starts operating, the relay does not respond to a surge in pressure, which leads to error f75 Vaillant. There may also be deposits in the bypass itself: check, rinse.

Expansion tank

Few people associate the correct operation of this device with error f75. But if the special tank is periodically not properly maintained, the pressure in the air chamber is below normal, it becomes one of the reasons for the appearance of such a fault code.

Rubber rubber gradually loses its elasticity, and deposits deposited from the system accumulate in the container body. The direct connection of the expansion tank with the hydraulic circuit of the boiler leads to the fact that part of the dirt gets into the Vaillant, to the pump.

Advice

When servicing, the tank must be dismantled after draining the coolant from the system. If the membrane is replaceable, its suitability for further use is assessed and a decision is made. The vessel itself is thoroughly washed, air (or nitrogen) is pumped into it (after installing the flask), and only then the device is connected to the heating system.

Strainer

Vaillant boilers have a miniature cleaning element installed in front of the pressure sensor to protect its cavity from sediment. During maintenance, it must be changed annually, like any consumable. Gradual contamination of the mesh leads to the fact that the sensor does not respond to changes in pressure in the pipe, and the automation periodically issues error f75.

Pump

To accurately diagnose the condition, it should be removed from the Vaillant boiler. Error f75 indicates no shaft rotation or low speed. The result is the same - there is no coolant circulation or it is weak, and the sensor does not detect this. Testing the pump is quite simple.

Electrical part

Since error f75 is caused by a small surge in pressure, it means that the operating Vaillant boiler pump does not create the required pressure. There are few reasons.

Salt deposits are removed by cleaning and washing. The damaged impeller is replaced. In service workshops, the functionality of the Vaillant boiler pump can be restored: they always have used products, and it is not difficult to find a replacement for any part. But it’s better to buy a new pump: it’s inexpensive.

Coolant

Many property owners, especially suburban ones, use antifreeze in heating systems. The special liquid loses its original properties over time - in professional slang it is called “rubber”. When the Vaillant boiler is started, the pump pumps the medium, which contains foam. As a result, voids (haverns) and the flow switch simply do not respond to changes in pressure. Hence the f75 error.

What is recommended

Error f 75 in a Vaillant gas boiler - How to fix error f75 in a Vaillant gas boiler (Vailant)

alexxlab05.12.2017

Vaillant gas heating systems are available in various versions. The most popular are wall-mounted double-circuit boilers Vailant VUW of three series: Turbo FIT, TEC Plus and Pro.

An analysis of the error tables in their instructions shows the identity of the problems that arise, and for the last two models the instructions are common. The article will help you understand the reasons for incorrect operation or stopping of equipment due to an emergency signal and give recommendations for eliminating them.

Vailant boilers are complex equipment equipped with various components, instruments, and electronics. And if we add “gas” ones, then such heating units pose an increased danger in terms of operation. Therefore, self-correction of errors is possible only within reasonable limits.

Next, the codes are deciphered, the reasons for which a competent user can cope with, especially since some of them are caused by external factors, and not by breakdowns of the Vailant boiler. Solving other problems is the job of a professional.

On a note!

1. Vailant errors during unstable power supply can be initiated by voltage surges. Eliminated by pressing the “Reset” button. If it doesn't help, you need to look for the reason.

2. Electrical engineering is called by practitioners the science of contacts. Errors appearing on the Vailant display are generated by the electronic module of the boiler based on information from the corresponding sensors. Troubleshooting should begin by checking the signal lines. What to look for:

Vaillant boiler contact groups

Repair practice shows that 85% of boiler errors are caused by precisely these reasons. This means they can be easily eliminated.

The instructions for dual-circuit gas Vaillant VUW TEC are taken as a basis. The symbolism of the codes for other boiler models may differ, but the meaning of the errors and their causes are the same. Knowing this, it is not difficult to find and fix the problem, regardless of the version of the heating installation.

*Error codes for the Vailant Turbo FIT series are indicated in parentheses

F20/F22/23/24 (F10|F11) – overheating

Errors occur when the volume of coolant in the system decreases, a sharp increase in temperature, or an exorbitant difference in temperature at the outlet and inlet to the Vaillant.

Recommendation : fill the circuit with water, bringing the pressure to normal (2±0.5 bar). Reset and start up the boiler. Repeated occurrence of the error is evidence of a problem.

Probable Causes

1. Leak. An autonomous circuit is a closed and closed system: natural evaporation of liquid is excluded. Loss of coolant is possible only in the event of mechanical damage or leakage. It is easy to find the problematic section of the route (device) by inspecting the house for signs of dampness, stains and streaks. Leaks rarely occur in the Vailant boiler itself: more often in the joints of pipes or heating radiators.

2. Reduced circulation rate. The coolant moves more slowly, and the boiler burner operates in the specified mode. Hence the overheating and Vaillant's error. What is the reason?

Vaillant boiler pump

Recommendation : if there is an alternative heat source at the site, the device must be removed and sent for service. Self-cleaning is ineffective, and after starting up, the Vailant boiler may start up again in a month or a month and a half. High-quality maintenance involves filling the cavity of the heat exchange device with an aggressive liquid, leaving it for at least a day, followed by flushing under pressure. This cannot be done on site.

When starting up Vailant for the first time, you need to check the installation of the check valve in the system. Incorrect installation blocks the channel, hence the boiler error.

F26 (F07) – problem with gas fittings.

You should ensure the integrity of the wires and the reliability of the contacts. It is not advisable to change it yourself - you also need to configure it correctly.

F27 – flame simulation error.

The probable cause is the ionization sensor: shorted wires, dirty electrode, dampness. If the boiler has been idle for a long time, you need to remove the casing and dry it (with a directed stream of warm air).

F28 (F04) – unsuccessful ignition.

There are many reasons for this error to appear. You can independently check only the flow of gas to the boiler burner, its pressure, the reliability of the signal circuits and grounding. Other defects - in the meter, main filter, Vaillant fittings, transformer, electronic board - must be determined by a specialist.

F29 – boiler malfunction, problem with re-ignition.

Probable causes of errors during autonomous gasification: gearbox failure, icing, LPG production. The remaining faults are identical to F28 , you cannot determine it yourself.

F33 (F05) – incorrect fan operation.

The error is caused by its breakdown, failure of the flow switch, or a malfunction in the electronic module of the boiler. If the power and signal lines are not damaged, you need to contact a specialist.

Problems with sensors

Errors can appear even when there are no complaints about the functioning of the Vailant or the heating circuit. This happens in two cases: a malfunction in the signal circuit or sensor. Read: line break/failure of the measuring element (short circuit).

Where to look for the reason

F00/F10 (F01/F03)

– temperature of the heating system, supply (boiler output).

F01/F11 (F06)

– similarly for the return line (input).

F02/F12 (F02)

– DHW circuit temperature.

F08/F13

– the same for the boiler (shown on the display of single-circuit versions of Vailant).

In the instructions for the Vaillant VUW TEC series boiler, the error table ends with code 91. Everything not listed in the article is a consequence of malfunctions of the electronic board or incorrect installation of the sensors after replacement. They are often inadvertently swapped, the wires are confused, and they do not provide a tight fit.

If repairs to Vailant or the system were carried out on your own, you need to remember a good rule: look where you last did something.

Practical recommendations

It is advisable to order and install a new German sensor of a new modification in the Vaillant boiler (article 0020023721). The price is quite high (around 11,500 rubles), but the warranty on it is 5 years, and the problem with the appearance of error f75 due to the “whims” of the flow switch will be solved forever. It is made in such a way that debris is excluded: special membrane material, polymer filling of voids in the sensor body.

If you have experience and methods on how to fix error f75 of a Vaillant boiler or what needs to be done based on your experience, write in the comments to this article, we will try to consider your option and analyze it in detail in this article or one of the following articles. You can also send photos and videos with comments and descriptions.

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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.

Vaillant boiler error f75 and elimination methods

That is, the actual pressure value in the system is constantly monitored by the control unit.

The normal pressure in Vaillant TEC series boilers is considered to be in the range from 0.7 to 2.8 bar. When filling the system, it is recommended to ensure a value of at least 1 bar.

If the pressure value recorded by the sensor differs from the normal range, this is considered a malfunction and the diagnostic system will generate an error.

Types of boilers produced

Vaillant produces gas and electrical equipment. Electric boilers are limited to one EloBLOCK model in several power options.

Gas appliances are presented in a more diverse range.

Single-circuit

Boilers with one circuit are designed to heat only the coolant of the heating system. For water treatment, you can connect an external boiler.

With two circuits

In dual-circuit models, water is prepared separately for heating and for domestic household needs.

Wall mounted

Wall mounted boilers are mounted using fasteners on the wall. Save space due to small dimensions. Household installations of low and medium power are manufactured in wall-mounted versions.

Floor-standing

Powerful domestic and industrial boilers are installed permanently on the floor. They have significant weight and dimensions. In some cases, they require a separate room - a boiler room.

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.

Decoding the code

This malfunction of the Vaillant boiler is usually interpreted as a lack of coolant. It’s easy to verify by looking at a number of thematic sites and forums. Hence the only recommendation is to add water to the system.

Error f22 belongs to the general category: the causes are different, and therefore a set of measures is carried out to identify and eliminate them. Correct interpretation: decrease in pressure in the circuit. Caused by a number of factors caused by problems with the system or Vaillant boiler.

First steps

Opening the tap at the bottom of the Vailant boiler

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.

Source

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.

Error interpretation

There is some confusion in the Vaillant manufacturer's instructions and its interpretation. Regarding error F75, it is said that its causes may be a faulty pressure sensor or circulation pump. At the same time, codes F73 and F74 are indicated in the same table. The first indicates a problem in the signal circuit of the flow switch (short circuit, broken wire, poor contact), the second indicates a breakdown of the sensor itself.

The peculiarity of the electronic circuit of Vaillant and Protherm is that it not only controls the operation of the pump, but also the moment it reaches the operating mode. This is how German units differ from boilers of other brands. If within 20 seconds after start-up there is no pressure jump in the system by 50 bar (that is, normal fluid circulation), the automation regards this as a malfunction of the pumping device and issues an error F75, which blocks the Vaillant boiler.

Decoding

Error f33 is generated by the electronic board of the Vaillant boiler. After starting the unit, the fan (turbine) is turned on by command from the ECU, and a vacuum is created in the chimney. This is detected by the sensor, and with normal flow through the exhaust channel of volatile combustion products, the relay contacts close the signal line. The ECU “sees” that there are no problems with the path, and gives permission to operate the gas valve and ignite the Vailant boiler. Accordingly, if the differential relay does not open the electrical circuit when the turbine stops, error f33 appears on the display.

Error F33 is displayed on the Vaillant control panel

The time indicated in the fault table (30 minutes) is approximate. In the Vaillant boiler, a timer is not included in this signal line. The delay in automatic operation is determined by the operating mode of the heating unit, weather conditions and a number of other factors.

Where to begin

Restart the unit. There is a Reset (or “On/Off”) button on the Vaillant boiler panel that clears the failure. Press for 5 seconds, release. If the cause of error f33 is voltage instability, the code will be cleared.

Button to reset error F33 for boilers atmoTEC pro, turboTEC pro

Advice

Powering the Vailant boiler from a UPS eliminates the appearance of false fault symbols. The unit, unlike a traditional stabilizer, provides autonomous power to the heating unit, and breaks on power lines or problems with the backup generator will not cause an emergency stop for the Vaillant.

Boiler stabilization scheme

First steps

Reset.

This is done with a button on the Vaillant boiler panel or by turning off/on the power. Error F75 caused by power surge disappears.

Heating circuit recharge.

When the pressure in the system is below a critical value, fault code F22 is displayed. But if the coolant level is “on the verge” (minimum permissible), there will not be a difference of 50 bar when the pump starts working. Consequently, error F75 will appear.

Bleeding air.

When bubbles accumulate in the coolant, the channel is not blocked, but the circulation speed decreases. This affects the correct operation of the flow switch, which issues a corresponding signal to the electronic board. And now it generates error F75 and stops the Vaillant boiler. Models of the TEC series are equipped with a special deaeration program (P.0): after its start, the fault code disappears.

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 experimenting

Reasons causing error F75 Vaillant

Bypass valve.

Its task is to protect the circulation pump mechanism from powerful hydraulic shocks. The valve has a spring, and in case of contamination it does not completely close the channel (half-open position). When the pump starts operating, the relay does not respond to a surge in pressure, which leads to error F75 Vaillant. There may also be deposits in the bypass itself: check, rinse.

Expansion tank.

Few people associate the correct operation of this device with error F75. But if the special tank is periodically not properly maintained, the pressure in the air chamber is below normal, it becomes one of the reasons for the appearance of such a fault code. Rubber rubber gradually loses its elasticity, and deposits deposited from the system accumulate in the container body. The direct connection of the expansion tank with the hydraulic circuit of the boiler leads to the fact that part of the dirt gets into the Vaillant, to the pump.

Advice When servicing, the tank must be removed after draining the coolant from the system. If the membrane is replaceable, its suitability for further use is assessed and a decision is made. The vessel itself is thoroughly washed, air (or nitrogen) is pumped into it (after installing the flask), and only then the device is connected to the heating system.

Pump

To accurately diagnose the condition, it should be removed from the Vaillant boiler. Error F75 indicates no shaft rotation or low speed. The result is the same - there is no coolant circulation or it is weak, and the sensor does not detect this. Testing the pump is quite simple.

Electrical part of Vaillant and Protherm pumps

Presence of voltage at the terminals. If it is not there, you need to assess the condition of the lamellas and wires: breaks, oxidation, short circuits. • Under the cover there is a 2 or 2.6 uF capacitor (check the value according to the inscription on the case). It provides the starting current. “Breakdown” or loss of capacity is one of the causes of error F75 Vaillant (the boiler pump will not start). A characteristic hum will be heard (when voltage is applied to the motor), but the shaft will remain in a static position. • There is a problem with the winding. To determine integrity, you need to measure its resistance: the norm is 275 Ohms. The ∞ symbol on the multimeter display indicates a break, when the nominal value deviates downward (R Recent

Source

Nuances of installation and operation

The installation of boiler equipment is carried out by gas company specialists in accordance with the instructions for the specific model.

Installation features of Vaiilant boilers:

The product has two levels of control: user and specialist. The first displays basic information and makes it possible to configure basic system parameters using keys and controls. The second is used for repair and maintenance and is protected by a special code.

Possible faults

There are two groups of problems that arise when using Vailant gas heating appliances. In the first case, the boiler does not work completely, in the second - partially. Possible causes of malfunctions and measures to eliminate them are presented in the table.

When the system is turned on, the display may show error messages. What typical fault codes mean, their causes and methods of elimination can be seen in the table.

Vaillant F75 boiler error

The most annoying failure among Vaillant boilers is a violation of the coolant circulation in the device, the boiler stops and we see the F75 symbol on the display screen. If you pick up the instructions for the boiler, you can find in one of the tables that this is error F75 and a brief description of what can fail and a list of faults.

The most common reason, which is also the main one, is clogging of the rubber membrane of the sensor with products of destruction of the heating system. Why does this happen and why, after installing a new sensor, does the problem close for a short period of time and start all over again? Everything is very simple, if you disassemble the old sensor and look at its design, you can see that there is a magnet inside the sensor, which is functionally necessary to change the magnetic field when the pump is turned on, the pump turns on, a small pressure surge occurs which is transmitted to the rubber membrane of the sensor, then oscillation is transmitted to the rod with a magnet, the magnetic field changes and a signal is sent to the main board, the boiler starts working. Everything is great, of course, but only for an ideal heating system without ferrous metal pipes and without steel panel radiators, which collapse over time and small particles circulate through the system and stick precisely in the pressure sensor, given the fact that it has a magnet. Thus, the sensor membrane, due to the magnet located behind it, perfectly attracts all the sludge and loses its ability to transmit any pressure surges.

So what's now? How to solve a problem? Shouldn't you constantly change sensors? The Vaillant company, of course, has already taken care of this and released a new fifth-generation boiler, while changing the firmware of the board; on the latest versions of wall-mounted boilers, error F75 does not exist by definition, the board no longer requests to turn on the pump, but what should those people who purchased a third one do? version of the boiler, and it was sold on the market for more than ten years. There is also a solution; a service kit has been released to eliminate this error with article number 0020023721, but it is only suitable for condensing boilers. At one time, the same kit was produced for conventional wall-mounted boilers, but was discontinued, kit article number 0020023722.

In this case there is only one solution , install the sensor from the Viessmann boiler with article number 7826025, its estimated cost is about 3,700 rubles, and forget the problem like a bad dream!

Source

Decoding

Error f64 is displayed when the heating unit is turned on or during operation. Informs about a boiler electronics failure. Appears, as a rule, after strong power surges in the network, lightning, or emergency situations. It is not advisable to immediately change the EPU - error f64 has several causes.

How to proceed

It does not help to get rid of error f64 - diagnose the unit.

Check what

Coolant temperature sensor

Boiler temperature sensor Vailant

Both are submersible types (for units of the atmo/ turboTEC series - overhead). They are constantly in an aggressive environment, which leads to metal destruction, short circuits, reading failures, and error f64. They are installed by screwing in; there is no need to dismantle them to check. The measurement is carried out relative to the body of the Vaillant boiler.

If, with the signal line open, the multimeter shows R = 0 (internal breakdown), the NTC is faulty and is rejected. After replacing the device, error f64 from the display of the Vailant boiler will disappear.

Flue gas temperature sensor

Flue gas temperature sensor in the Vailant boiler

Checking for short circuit is identical to the method described above (for NTC). In Vailant boilers of the atmoTEC series, the sensor has an original design (AtmoGuard control system). The device contains 2 sensor devices, the location of which (one closer to the burner, the other at the end of the chimney pipe) ensures low response inertia. Short circuit of the sensitive element, short circuit on the line causes error f64. Check the condition, eliminate the defect, and the fault code will be cleared.

Electronic board

Diagnostics of EPU is the prerogative of the service technician. A preliminary performance assessment is performed on site by entering the menu to the 2nd level. To fully test and identify the cause of error f64 of the Vailant boiler, a test on a simulation stand in a hospital setting is necessary. But a number of defects that cause fault codes can be determined independently, and some can be eliminated.

Check the Vaillant boiler control board

What to do

Inspect the board for defects: cracks, chips, damaged tracks, dark spots (burnouts), melted housings of radio components. Each factor causes a Vailant boiler error.

Remove dirt, dust, condensation from the surface. They cause short circuits and the appearance of the f64 code.

Advice

There is no need to carry out a more “deep” diagnosis yourself. There are a lot of recommendations on the Internet, exchanges of opinions on the experience of eliminating the f64 error of the Vailant boiler “on the table”. At the same time, it is overlooked that the circuit diagrams of electronic boards and the design of units are different (depending on the model and year of manufacture). If you couldn't solve the problem, call a service technician.

Typical errors

Knowing the error codes of the Vailant boiler, you can diagnose almost any malfunction. And having experience in repairing heating equipment, nothing prevents you from dealing with the breakdown yourself. The codes are displayed on digital indicators, representing two-digit numbers with the letter F. Let's look at them in more detail.

Error F28

A fairly common error that occurs when the ignition unit cannot be started. As a result, the equipment cannot start working. Error F28 in Vailant boilers can indicate either a breakdown of the system board or a malfunction of other components - the high-voltage ignition transformer, gas magnet, gas valve, ignition sensor and much more. It appears when the conductors break or there is insufficient pressure in the line. Its appearance is often caused by a simply closed gas valve.

To fix error F28, follow these steps:

If all nodes are intact, there is a high probability of an error directly on the system board. In this case, you need to contact Vailant service for its repair or complete replacement.

Error F75 may also indicate problems with the on-board water pressure sensor - it cannot recognize an increase in pressure after the pump starts.

Error F75

Another common sign of breakdown. Error F75 in Vailant boilers indicates problems with pressure in the heating system. It occurs after starting the circulation pump . Usually in this case the pressure rises by about 0.2-0.4 atmospheres. If this does not happen, the problem may lie in improper installation of the system. First, you need to check the functionality and correct connection of the expansion tank (expansomat), and then de-air the circuit.

After this, we check the functionality of the pump - it should drive the coolant along the circuit. A faulty pump must be replaced; they are usually not repaired.

Errors F0, F1, F2, F3 and F4

The first two occur in Vailant heating boilers if the coolant temperature sensor (NTC sensor) fails. It must be replaced with a sensor of a similar model. Despite the absence of vibrations, the connecting conductors may also fail - check their integrity with a multimeter. You should also evaluate the quality of the connections, inspect the connecting plugs - codes often appear due to oxidation of the contacts. Codes F2, F3 and F4 are caused by the accumulator sensor.

Errors F5 and F6 (and F15 and F16)

This code is typical for Vailant Atmo series boilers with atmospheric burners. It indicates a breakdown of the traction sensor or a break in the connecting wires. We recommend checking the integrity of the conductors and testing the sensor itself. If a breakdown occurs after disassembling and reassembling the equipment, we check that all connections are correct. In turbocharged units, codes F15 and F16 occur.

Codes F10 and F11

Their appearance means a short circuit in the supply and return temperature sensor circuits. Not only the wires need to be checked, but also the temperature sensors themselves. We test detachable connections in the same way.

Errors F13 and F14

If one of these codes appears on the digital indicator, it means that the coolant has overheated - it has heated up to a temperature of +130 degrees. For Vailant boilers, this value is critical, so the equipment is immediately turned off. If the water in the circuit is clearly cooler, there is a short circuit in the sensor itself or in the connecting wires.

Code F20

Indicates problems with the supply temperature sensor. It needs to be checked, all connections are checked in the same way. In some cases, the code indicates overheating of the coolant.

If error F22 occurs, you need to test all circuits responsible for the operation of the circulation pump and the coolant pressure sensor in the circuit.

Codes F22, F23 and F24

Error F22 is common, indicating a variety of malfunctions. It appears when there is no water in the heating circuit. Water can leak out through the smallest cracks and cracks, and problems with the pressure switch and circulation pump are also possible. In rare cases, the motherboard is to blame.

F23 at the first start indicates a problem with the coolant - there is not enough of it or the installer managed to confuse the supply and return pipes. In other cases, the culprit is the circulation pump, which requires checking and replacement. Code F24 indicates that the coolant temperature in the supply pipe is too high - we check the pump, temperature sensors and circuits. Last of all, we sin on the payment.

Error F25

In Vailant boilers, it indicates that the temperature of the combustion products in the chimney is too high. When overheating is detected, the equipment turns off. If the gas equipment and heat exchanger are working properly, we test the sensors and electrical connections.

Code F27

Some errors in Vaillant boilers indicate several possible malfunctions at once:

In the latter case, turn off the equipment, wait a few minutes, and restart.

Error F29 may appear if the ignition system is malfunctioning - check all its components.

Error F29

It is widespread and appears when there is a simple drop in pressure in the gas line and when the gas supply is completely stopped. As a result, the flame disappears, the equipment turns off, and the above code appears on the display.

Error F32

Characteristic exclusively for Vailant condensing boilers. Diagnoses a malfunction of the fan responsible for removing combustion products. In this case, check the fan and connecting wires. Sometimes the culprit is the electronic board that controls the equipment.

Errors F35 and F36

When these codes appear, open the windows and ventilate the room, check for any foreign odors. It is quite possible that combustion products go directly into the room instead of the chimney. Codes are also displayed on the display if the flow of fresh air is disrupted. The situation is typical exclusively for Vailant atmospheric boilers.

Code F61

Serious error related to the operation of the gas valves. Indicates their malfunction and the breakdown of the electronic board. In rare cases, the code is displayed when the connecting wires are broken.

Code F62

The boiler “sees” the flame for longer than four seconds after closing the gas valve. Possible reasons:

Please pay special attention to this error.

Common mistakes of Vailant gas heating boilers

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.

Features of operation

Particular attention should be paid to the gas burner, since it is the one that clogs most often, which leads to the inability to fully control the flame level. Carbon deposits must be removed from the internal surfaces of the working chambers. When using gas, there will be little of it, so the user will not experience any particular difficulties. It is very important to maintain the chimney so that it fully copes with its functions.

Malfunctions of the Vailant double-circuit gas boiler differ from the single-circuit model due to its more complex design. The device simultaneously acts in two capacities, so it has a double load. Let's face it, if the boiler operates only during the heating season, then the water heater has to work all year round without breaks. But it is still necessary to allocate one day during which the system will be turned off and receive appropriate service.

It is better to do this in a timely manner and save yourself from problems that may occur at the most inopportune moment. The most common problem with this category of heating equipment is water leakage at the joints. Therefore, you need to pay special attention to sealing and use the most modern means for this. The connection must be reliable in order to serve for many years and not create any problems for the owners.

Common Mistakes

It is also a fairly common problem when exhaust gases are not completely released into the atmosphere. A smoke exhauster can be of great help here, as it can even correct a not entirely correct chimney installation. The gas burner also needs to be cleaned at least once a year, and more often on the water heating circuit. To resolve more serious issues, it is better to contact the service center.

Every modern boiler is equipped with an automatic system that monitors the status of all systems and, in the event of emergency situations, quickly stops gas leaks. Therefore, there is no need to worry that an explosive concentration may occur if the boiler breaks down when no one is home.

However, it is also worth considering that the computerized control unit operates on electricity, so it is necessary to ensure an uninterrupted supply of voltage to it so that all systems continue to function as normal. For this purpose, UPSs with different battery capacities are used. It would not be superfluous to install a voltage stabilizer.

Decoding the main error codes

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

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