Vaillant boiler malfunctions: repair and typical error codes - F28, F75, how to fix the hot water option

Modern heating systems are quite reliable. But still we have to state the fact that they can all break arbitrarily. At the same time, no brands and models, no diligence of engineers exclude such a problem.

Repair of various models

According to the manufacturer's instructions, the Vaillant TurboTEC Pro 28 kW gas boiler must not be repaired in such a way that changes occur in the boiler itself, on the lines supplying water or gas, in the electrical network or in chimneys. Tightening and loosening the threads of all connections can only be done with open-type wrenches. It is impossible to use pipe pliers, extension cords and the like equipment for this purpose.

The pressure is checked as follows:

  • the shell is removed;
  • the distribution box leans forward;
  • the gas valve is closed;
  • the screw in is loosened;
  • a pressure gauge is connected;
  • the gas shut-off valve opens;
  • the device is started at full load;
  • connection pressure is measured.

If you can't fix the problem on your own, you should follow these steps:

  • the boiler needs to be stopped;
  • remove the pressure gauge;
  • check the tightness of the screw fastening;
  • fold back the distribution box;
  • return the skin to its place;
  • wait for the representatives of the gas service.

Important! The diagnostic data has two levels. The second is available exclusively for specialists and only after entering a password. To know what errors need to be fixed, it is necessary to study the proprietary error codes.

Both single-circuit and double-circuit boilers, which consume a lot of gas and produce an extremely hot flue stream, do not need to be repaired. The upper heat exchanger must be cleaned and washed. With a low hydraulic resistance, the company advises to tighten the supply tap. If there is no spark at all, do not waste time cleaning the gas valve. The problem is almost 100% related to the system electronic board. If the AtmoTEC Plus boiler changes pressure abruptly when the temperature changes, it is required to pump the expansion tank.

What do the error codes mean?

    In many cases, there is no need to disassemble the device yourself or guess what the problem is. All necessary information is provided to the consumer by error codes. But you need to know them. A symbol starting with S indicates a certain status of the machine. And codes starting with F show certain failures.

          When you first see this or that conditioned signal, you should not be afraid. You should try to reboot the electronics. Only when the same code appears again, you need to take special measures. F0, as well as F71 indicates that the circuit that supplies the thermal sensor that measures the temperature of the coolant is broken.

          It is necessary to find out such points as:

          • whether the sensor itself is operational;
          • is the contact of the plug good;
          • whether the wiring is reliable.

          F1 demonstrates that the return line temperature meter has cut off. F2 says that the thermal fill sensor is malfunctioning. When the F3 signal appears, it is easy to understand that the circuit of the same sensor, but already responsible for controlling the drive, is damaged. You can see the F5 error only in Atmo wall boilers, and it means that the connection with the external smoke removal indicator has disappeared. Code # 6 indicates a wiring fault with the internal sensor located in the tap.

          By code number 10, specialists identify short circuits of supply thermistors. F11, F13 show the same state, but only for the return stroke thermistor and for the hot start meter, respectively. For a closed external recognizer for the removal of gaseous products, two errors are characteristic at once - F15 and F16. The F20 code indicates that the system is malfunctioning due to excessive heating. And F22 speaks about another point - there is not enough water. A similar picture is indicated by the F23 code, which is often associated with a malfunction of sensors, pumps, or at low performance.

          Signal No. 24 indicates that not only the level of the coolant has decreased, but also its heating has increased significantly, and the pressure has decreased. F26 means that a failure has occurred in the gas valve. And also you should suspect a mistake in connecting the servo motor. F27 lights up if a flame is detected with the fuel valve closed. More serious F28, this code appears when the burner cannot be started.

          You will have to control the meter, fittings, pressure measuring relay, and the main module.

          F29 is shown when the fire is extinguished due to interruptions in the gas supply. It remains only to wait for the restoration of his approach. If the wait is delayed, you will have to contact the service responsible for the supply of blue fuel. It is also useful to check if the boiler is properly grounded. Error F32, F37 occurs only in condensing boilers. She reports that the fan does not rotate as it should at a particular moment (other models demonstrate this with the F38 code).

          The TurboTEC model has a special bug not found in other machines - # 33. It is easy to find out from it that the relay, which measures the pressure, does not work. The F36 signal is received when the draft meter detects its weakness and the penetration of combustion gases into the boiler room. And F42 lights up if the operation of the resistor responsible for the conditional coding is interrupted. When signal No. 49 is received, it is necessary to check the status of the eBus information bus.

          Code 53 indicates an incorrect setting of the combustion process. On signal 54, it is necessary to deal with the elimination of failures in the fuel supply, while it is necessary to sequentially open the valve, increase the pressure and visually assess the serviceability of the shut-off valves. Code 56 indicates a malfunction of the main parts of the unit that burns fuel. If the problem persists when connecting the plug, check the valve. And code 57 is issued when setting the Comfort mode with erroneous adjustment. It is also worth suspecting that the ignition electrode has corroded.

          If the cleaned parts continue to work poorly, a completely new part will have to be installed.

          F61 can illustrate either a shorted cable, an open circuit, or a fuel valve failure. The signal F62 determines the delayed shutdown of the valve, caused by the poor response of the control electrode. The display of the number 63 indicates the so-called EEPROM breakdown, which is eliminated exclusively by service centers. Violations, shown by numbers 64 and 67, indicate that the electronic "filling" of the boiler is damaged or the sensors are out of order. A relatively minor problem is error 70, which occurs when the step of entering the code of a new boiler is skipped after installing a replacement display and electronic components.

          The F72 index allows you to recognize violations in the thermal sensors of the line, which are responsible for the flow or located on the return circuit. F75, as it were, notifies the owners of the boiler that even starting the pump does not help raise the pressure. We will have to release the air accumulated in the system, adjust the settings of the bypasses and expansion tanks. F35 is a kind of "partner" of the 36th error.

          This error appears with the following faults:

          • if the air or gas outlet is blocked;
          • when due to weather conditions or due to structural violations, the thrust is violated;
          • with abnormal ventilation;
          • when the boiler room overheats;
          • if the boiler is too close to the wall.

          F76 lights up in the display when the primary radiator is too hot. And F77 indicates that the diverter valve or the pump responsible for condensation is working too badly. F51 signals the overturning of the draft and deliberately incorrect operation of the chimney. Signals 80 and 91 that appear at the same time immediately indicate a short circuit in the secondary radiator sensor. If errors 81 and 91 are combined, there is a malfunction in the loading pump.

          You can fix this failure by following these steps:

          • release air;
          • check for violations of cables, sensors and impellers;
          • find out if the heat exchanger is dirty, clean it if necessary.

          F83 signals an incorrect measurement made by thermistors on the receiving and returning lines. They simply add coolant or adjust the placement of the thermistor. Codes 84 and 85 also denote incorrect information from thermistors, but problems need to be eliminated differently - to swap blocks or eliminate other wiring defects. Deformation F93 demonstrates that combustion is not correct. When cleaning the venturi nozzle does not help, you need to change the nozzle to a more correct device. Defect Con notifies that the exchange of information with the control equipment has been disrupted, you will have to contact the service organization.

          The Fxx code tells about software failures, 5ER is not so much an error in the usual sense of the word as a reminder of the need for maintenance.

          Vaillant boilers can also issue intermediate messages that are not errors. So, S0 – S8 tell consumers about the running heating mode. When the boiler is preparing hot water, the display shows signals S10 – S17.

          Other status signs are as follows:

          • 30 - external thermostat blocked heating;
          • 31 - the system is switched to summer format and cannot heat the house;
          • 33 - frost protection works, the system is locked for 1/3 hour.

          It so happens that the heating seems to be running, but the regulator instructs the boiler to work at +20 degrees. In this case, signal 36 is displayed on the screen. But code 41 says that too high nominal pressure is developing inside. S42 can be displayed when the burner is not working, when the valve on the branch is activated or the condensing pump is damaged. S51 is a condition where combustion gases enter the room.

          Error 53 is detected when there is a lack of water. The boiler will correct the situation or wait for help from the owner in this for 150 seconds. S54 means the system is waiting for action for 20 minutes. There is no reason for alarm when the status S98, 96 or 97 appears, since these are signs of work in test mode.

          It is possible to minimize the occurrence of all the listed problems if the boiler is inspected in a timely manner and maintenance is carried out.

          Customization and management

          The handling of Vaillant boilers means their competent transfer 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 money for gas and not overheat the house. The solution to the problem is to close the heating circuit to a short stroke, using a tap and jumpers.

          Important: it is imperative to connect the inlet and the outlet of the second circuit in such a way that the expansion tank is within the circuit. In fact, in this mode, the boiler works like a small-capacity boiler.

          If the equipment is made according to a scheme with artificial circulation, everything will be even simpler: the circulation pump should be disconnected from the circuit and the boiler inlet pipe should be sealed. 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 rationing the consumption of hot liquid. It is required to pump up the expansion tank if the pressure level continuously decreases and rises, changes unpredictably. A steady drop in pressure in the system is not so easily eliminated, it is imperative to find a place where the coolant leaks out 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 give results or they persist for too short time, you need to inspect the tank. Often, its outer shell is depressurized and air is allowed to pass through. But even more often the performance of the spools is disrupted, which also begin to undermine.

          The tank itself is pumped up in the following stages:

          • wrap up boiler, supply and return taps;
          • open the drain fitting until it is completely drained;
          • connect the pumping unit by means of a spool, in no case overlapping the union.

          Any type of pump is useful for work; you can take a car and a pressure gauge from the car too. The air is pumped by the pump until the flow of water from the pouring nozzle stops. Further, the air is released and its introduction is repeated, continuously monitoring the readings of the manometer. It should show 1.1–1.3 bar, more precise information is given in the technical documentation. Now you can close the pouring nozzle, open all previously closed taps, feed the boiler in a regular way to 1.2–1.5 bar, and then start heating.

          It is especially important to control internal pressure if the house or other structure is visited only periodically. It's 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 may drop due to cooling lower than needed for the boiler to work. Even after the resumption of the power supply, 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 monitored constantly. No less bad is the situation in which the level of pressure is constantly increasing. Of course, a well-chosen and correctly installed safety valve corrects the problem to some extent, but it is better not to rely on it, since it is still more of an emergency measure.It is always worth remembering that pressure control deserves increased attention.

          Causes of problems

          In order for possible reviews of boilers of this brand to be favorable, it is necessary to pay great attention to the prevention of malfunctions and their elimination. It should be noted that not all problems are indicated by codes, some arise without warning. The situation when the boiler does not turn on at all may appear due to incorrect connection of "zero" and "phase".

          Also, the problem may be related to the following:

          • air abundantly mixed with gas;
          • weak pressure in the gas pipeline;
          • grounding errors;
          • torn cables;
          • illiterate connection to the gas pipeline.

          When there is no hot water at all or the boiler does not heat it well, it is required to assess the condition of the flow sensor. Sometimes it gets dirty, the liquid moves, but the automation does not give the command to the fan to blow through the furnace and fan the fire. Having released water from the hot water circuit, they achieve saturation of the pipes with air. Following this, it is necessary to abruptly unlock and tighten the water taps in front of the boiler in order to remove dirt from the fan or sensor due to pressure drops. If the pressure rises or falls unpredictably and hot water drips from the cold tap, damage to the secondary heat exchanger can be assumed.

          Sometimes the boiler hums when turned on - no need to be afraid to open it. It is required to make sure that no tubes or other parts come into contact with the body. Then there will definitely be no problems with extraneous noise.

          You should also check the following reasons:

          • saturation of pipes with air;
          • oxygen content in water;
          • the appearance of scale;
          • fan operation difficulties.

          For instructions on using the Vaillant gas boiler, see the following video.