Vaillant boiler does not turn on hot water

What to do if the gas boiler is broken and the hot water does not turn on? Instructions for diagnosis and repair

Installation of double-circuit gas boiler can effectively solve the problem of hot water supply. But what to do if the hot water in the gas boiler does not turn on? Agree that you should not immediately panic and call the emergency service or service center.

We will get acquainted with the principle of work of a two-circuit boiler, we will tell about the reasons which can lead to interruption of hot water supply and the ways of elimination of the arisen failures.

Understanding the nature of the equipment, you can not only independently identify the causes of failure, but also to eliminate most of the faults and restore the hot water supply in full.

Diagnosis of Vaillant Turbotec boilers failures

Can you tell me what is the cause of malfunction if the gas boiler Vaillant Turbo Tech Pro does not turn on?? How to eliminate the fault?

Long ignition time of the gas burner shows that there is a clogging of the flame ionization sensor. In order to fix the problem it is necessary to clean the sensor and restart the unit. Sensor draught sensor malfunction. Gas supply to the burner is interrupted. The sensor should be cleaned or a new one should be installed.

What is the cause of malfunction if there is no heating when the boiler is in operation? What is the problem? We use the unit for a total of six months.

Inspect the main circuit filter. If there is a clog in the filter, disassemble and clean the filter element. Impeller of circulation pump has a breakage. To inspect the hydraulic pump and to make replacement, if necessary. Also check the water circulation in the heating pipe. Worn or dirty heating piping limits the amount of water in the system, causing the appliance to stop heating.

How to fill the gas boiler with water?

This procedure must be carried out in a certain sequence. Open the vent valves that are installed in the radiators and check the operation of the auto-air vent on the boiler. Slowly open the filler tap, observing the reliability of function of all the air venting mechanisms of the heating system without exception. Close the air bleed valve on the radiators as soon as water starts to appear. After that, close the make-up tap and let the air out again through the radiator cocks. Run the unit and wait for it to heat up to the desired temperature in the heating circuit, then turn off the hydraulic pump and perform secondary venting.

Tell me why the wall mounted gas boiler Vaillant Turbotec dampens?

Flame detection malfunction. Low gas pressure. Deterioration of the gas supply. Malfunction of gas valve. Components of the ignition unit are broken or the contacts are damaged. At the same time, the control board can malfunction.

I don’t understand the problem when the boiler shuts down? How to fix it? The unit has not been used for more than half a year.

Causes of the interruption of work are incorrectly chosen capacity of the unit, reduced gas pressure, problems with the flue duct, power outages, automation failure.

Can anyone tell you what the problem is if the pressure in the boiler is constantly dropping? Installation of the boiler was carried out last year. What is the problem?

Ecotec Boiler no hotwater instead radiators heating. plumber West Hampstead

The presence of air in the heating system. Broken air exhaust valve. It is necessary to change it. The filter of the heating system is dirty. Clean the filter. There is a leak in the boiler or in the heating pipes. Water make-up valve failure. Fault with the flow sensor. Check and replace if necessary. The circulating water pump has a damage. Insufficient rotation due to worn blades.

Could you please explain why the boiler Vaillant Turbo Tech Pro 24 switches on and then switches off? How to fix it? Unit has been in operation for no more than six months.

No flame detected by the electronic board: Neutral and phase reversed. Connect the neutral and phase correctly. If it did not give the result, the automation unit should be replaced. The flame detection electrode cable is disconnected or broken. Reconnect or change wiring. The gas pressure is extremely low. Adjust for higher pressure.

vaillant, boiler, does, turn, water

Would like to find out why the boiler does not ignite? The unit was connected last year. What is it?

No ignition. Malfunction of the gas mixture. The gas valve must be in the open position. The gap between the electrodes is not correct or they are bent. Lack of electrode discharge. Suspected power supply malfunction.

Why at the moment of starting the gas boiler you can hear a suspicious bubbling and then the gas burner starts to extinguish. On the display there is an error that indicates overheating. We are advised to replace the heat exchanger. How to eliminate the problem?

Blockage of the unit due to overheating of the heating medium does not always indicate fouling of the heat exchanger. Unnecessary sounds can also be heard when there is a build-up of lime inside the heat exchanger, and due to air in the heating line. But first check that the temperature sensor, 3-way mixer and circulation pump are in working order.

What is the cause of malfunction if the gas double boiler Vaillant Turbotec Pro makes crackling noises when heating? For example, the gas burner fires up, the temperature rises, then you hear an unusual metallic sound. But if you loosen the screws fixing the outer panel, in this case the rattling stops. What’s wrong??

Occasionally the appliance may hum and rattle, mainly when the main burner is out of operation. This is caused by a disproportionate heating of the heat exchanger lamellas, because the element is blocked or there is lime scale on the exchanger. You need to remove scale and dirt from the boiler as soon as possible.

Why the gas boiler does not turn off when heated to a predetermined temperature? Heating continues up to 90 degrees, then it goes into failure. If you reset, the cycle resumes.

We assume that the electronic board is damaged, the temperature sensor requires replacement, the button of the safety sensor is broken. It is possible that there is a malfunction in the automatic regulation.

How can I reduce the pressure on the boiler Vaillant Turbotec Pro VUW?? And is it allowed to reduce the pressure of the gas fuel? There is a regulator in the appliance, which equalizes the gas pressure or there is no need to make this correction?

vaillant, boiler, does, turn, water

It is recommended to use the regulator to equalize the pressure of the fuel supplied to the unit. If it is quite low, the gas burner will not ignite, when it increases, you can see the flame pulls away from the wick, and the gas burner extinguishes shortly after ignition. Further adjustments. Actively heat the appliance. Open the chimney completely. Set the main gas burner to maximum, in this case the flare looks yellow and blue. By closing the inlet tap you remove the yellow light. Then conduct a test of the functioning of the boiler unit in different modes.

Possible malfunctions that occur less often

If the required error code is not listed here, it means that only a service technician can solve it.

  • F0, F The fault is in the NTC sensor which controls the temperature in the flow line (F0) or in the return line (F1). It is necessary to check not only the sensor, but also its cable;
  • F2, F3, F The NTC sensor malfunctioned. Perhaps the plug is badly inserted or the sensor or cable itself is broken;
  • F5, F6 (Vaillant Atmo). Problem with the operation of the sensor ensuring the safe exhaust of combustion products. Must check if it is connected correctly, or if the failure is due to a broken cable or the sensor itself;
  • F10, F There is a short circuit in the temperature sensor in the supply line (F10) or in the return line (F11). F2, F3, F The NTC sensor has malfunctioned Check the above;
  • F13, F Unit temperature has exceeded 130 degrees and there is a short circuit in the hot start sensor. Check everything described above;
  • F15, F16 (Vaillant Atmo). Short circuit in the sensor responsible for flue gas outlet. Check everything described above;
  • F The boiler has overheated;
  • F Not enough water in unit and temperature between flow and return lines is very different. It is worth to check sensor connection on both lines, pump and cable or board functionality;
  • F The problem is similar to the previous one. insufficient heating fluid. Check the same things as in p.8;
  • F Appliance has switched off in an emergency due to too high flue gas temperature. The NTC sensor, cables and plugs should be checked;
  • F Boiler reports flame although valve is closed. The cause could be a problem with the flame sensor or the magnetic valves;
  • F32 (condensing boilers). F Faults with fan speed. Most likely the problem is in the unit itself, but you should also check the board, cable and sensor;
  • F33 (Vaillant turboTEC). Pressure switch does not close contact after half an hour of heat request;
  • F The voltage on the bus eBus decreased. There may have been a short circuit in it, or it is severely overloaded;
  • F Control signal is not being sent to the valves. You need to check the valves, the cable and the circuit board;
  • F Valve trip delay failure. Check to see if it is leaking gas and if the nozzles are clogged;
  • F The electronics unit has overheated. The cause is either external or a faulty unit;
  • F Low water pressure. Either the problem is in the sensor itself, or it has a short circuit;
  • F High water pressure. The cause is stated above.

How to troubleshoot two-circuit boilers Vaillant

Boiler gas wall two-circuit Vaillant has several options for malfunction. Most of them are caused by improper operation. But there are more complicated situations, which can be solved only with continuous prophylaxis and diagnostics.

What faults can occur in Vaillant boilers

Troubleshooting gas two-circuit wall mounted boiler Vaillant is divided into several groups, according to the cause of the malfunction.

If necessary, all malfunctions can be eliminated very quickly. It is enough to know the main malfunctions and error codes, which will be reflected on the electronic display.

Important! In the absence of the required experience, the full repair should be handled by a specialist, who will immediately identify the cause of improper operation and eliminate it.

Gas boilers two-circuit wall mounted Vaillant have several common malfunctions:

  • Error F22. lack of water or insufficient water to work. Can be fixed by checking the pump, which may be jammed. You will also need to check the cable connection to the pressure sensor. Also such error pops up at the display at a weak circulation level.
  • F28 error. the equipment cannot be started. There are many reasons for this error, including wrong connection or oversaturation with air. Most often occurs with improper installation, as well as neglecting the operating instructions. The solution is a complete check of the installation and a change of settings.
  • F29. burner goes out or doesn’t light up at all. Among the most common causes are improper grounding, as well as a failure in the gas supply. The gas valve may be damaged or not working properly. In such cases, it is worth checking initially the pressure in the system, as well as the presence of air for ignition.
  • F36. product of combustion is escaping from the system into the room. Usually the source of the problem is poor ventilation or poor traction. In addition, such a failure occurs at high temperature in the room.
  • F75. pressure doesn’t increase, but pump is working. This situation can occur if the pump or pressure sensors are broken. In addition, air can accidentally get into the system or the expansion tank was not properly connected.

Important! When installing equipment, diagnosis should be done by a specialist or someone with experience, as this will help avoid most mistakes.

At installation diagnostics should be carried out beforehand which will reveal all malfunctions. This procedure is obligatory. Most malfunctions are due to improper installation and operation. In addition, breakdowns are also more likely to occur under these conditions.

It is worth considering that malfunctions can be caused by a variety of reasons, including mechanical damage or failure in the electronic control system. Most problems will not occur with annual maintenance and proper operation.

Also note that if there are any malfunctions, the electronic scoreboard will not function. Each case has its own way of eliminating the negative factor. If there is no understanding of what the problem is, it is better to contact specialists who will eliminate the problem without additional damage to the equipment.

Tips from the specialists

There are a few tips from experts, which are worth taking into account. In particular, a number of tips concern prevention and initial use of the boiler. Recommendations:

  • The model must meet the needs of the heating system;
  • Connection should be made strictly according to the instructions;
  • Any small deviations from the operating cycle should be checked immediately;
  • Diagnostics should be performed before the first operating run;
  • install the equipment by professionals, otherwise malfunctions may occur during the first operating cycles.

Important! Boiler of any type must be fully serviced. In the opposite case, in time will begin to deteriorate the operating cycle.

Most users have questions that can only be answered by specialists. There is also an answer to each question, which allows you to solve the problem. Tips:

  • If there is no reaction to turning on the water and a set of sounds that come from the equipment itself, it is worth checking the line for the gas supply trimmer, as well as the gas meter.
  • In case of pressure jumps, which are caused by the expansion tank, it can be simply pumped up.
  • If the pressure sensor malfunctions, error F75 will pop up. To eliminate this, simply turn down the pressure tap.
  • In case of alternating shutdown of equipment and delivery of alternating hot and cold water it is necessary to set the minimum pressure.
  • In case of delays in switching the boiler from one mode to another and if there are sounds similar to gurgling, it is necessary to evacuate the excess air.
  • In addition to water, only a heat transfer medium specially selected for the boiler can be used. No other fluids should be present.
  • If the equipment stops completely and the panel fades, the fuses need to be checked.
  • If the flame is blinking and can not be turned on, clean the filters and check the sensors.
  • If there is good cold water pressure but hot water does not come out well then the heat exchanger must be checked and replaced.

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

The display can show various error codes, but the problem is often complex. The error that prevents the equipment from entering the operating mode is displayed.

Defects must be corrected after finding them. Further the full inspection of the equipment and adjustment is carried out. After that, start the diagnostics, which should check all the modes and capabilities of the boiler.

Only after all these procedures can the equipment be put into operation. It is also important to perform cleaning after repair or troubleshooting, which is necessary.

Boiler Vailant: malfunction, diagnostics, error codes and causes of breakdowns

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

After all, the gas boiler. the technique is complex, from the competent actions in case of emergency, will depend on how the boiler Vaillant will work in the future.

Troubleshooting most often requires a professional approach, but something can be done yourself.


Each Vaillant boiler has a diagnostic system included in the electronic unit. Information on the status of the unit is displayed on the LCD screen in the form of a code (in the “T” and “R” fields). ч. and past mistakes).

Before a specialist arrives, you can assess the performance of the device on your own:

  • Check all inlet and outlet connections for leaks (this includes carbon monoxide, condensate and DHW drains).
  • Check: whether there is no contamination in the chamber of the reduced pressure.
  • Check all electrical wiring: whether the connectors and plugs are tightly seated.
  • Check the condensate drain and siphon for salt and lime deposits. Clean if necessary.

Inspect the gas burner. it is most often clogged with soot. It is necessary to clean inner walls of working chambers and chimneys.

There is not much soot in the gas equipment, so the user will not have much trouble.

Error codes of Vaillant boilers

So, what do the numbers on the monitor mean? Let’s start with the most common malfunction of a gas boiler Vaillant, which can cause panic in the owner, when the boiler stops starting at all.

F28 error

Failure. the ignition of the device is blocked. There may be several reasons, these are:

  • No gas supply due to a broken gas pressure regulator or meter.
  • Gas oversaturated by air.
  • Insufficient gas pressure is coming (change in settings).
  • Gas valve is closed (it also happens, check it).
  • Gas magnet is out of order.
  • Errors during installation, connection to the gas line.
  • Cable breakage.
  • Breakdown in the ignition transformer.
  • Fouling on the electrode sensor.
  • Control board damage.

F0 and F1

The problem is in the NTC temperature sensor, in the first case on the flow, in the second. on the return. The problem could be in the sensor or in the cable. It’s also good to check the plug on the electronic unit.

F2, F3, F4

The problem is in the NTC storage reservoir fill sensor. Leaky plug insertion, defective cable, loose connection to the housing. Sensor faulty.

F5 (Atmo only)

Open circuit in outdoor traction sensor circuit. The cause could be:

F6 (Atmo only)

Breakage of internal draught sensor circuit. Check the same as for error F5.

The electronic panel of the boiler Vaillant Atmo


Short circuit in the sensor of supply / return. Check the sensor, sensor plug, cable.

F13, F14

Short-circuit in the hot start sensor. Such boiler error can occur if the temperature exceeds the threshold of 130 0C. Check: short to ground, short circuit in the cable harness, sensor itself.

F15/F16 (only for Atmo)

Internal/external draught diverter short circuit. Check the serviceability of the sensor, cable, plug.

Overheat protection, STB sensor. Boiler won’t turn off due to faulty or poor connection of supply temperature sensor.

Dry run. It is possible that you just need to add water to the system. But the problem can also be in the automatics.

  • water pressure sensor;
  • Reliable connections of pump cable and water pressure sensor;
  • pump function: it could be jammed.
  • Either the pump capacity is insufficient.
  • The electronic circuit board is defective.

Insufficient coolant. Check it by comparing the return and supply line temperatures. normally there should be a small difference.

The connection of the flow and return outputs may have been mixed up. But if the boiler was connected correctly and worked for a long time, the problem is in the pump. It could be blocked or has failed for other reasons. The problem can also be in the sensor or in the board.

Insufficient thermal fluid. Supply temperature is too high. Proceed in the same way as with the previous error:

Flue gas temperature rises, triggering emergency shutdown. Need to check:

Valve is closed, but automation “sees” the flame. It can be a malfunction in the flame sensor or a defect in the magnetic valves. Also electronic board malfunction.

Flame goes out in operating mode. Ignition attempt fails. Check if the appliance is properly earthed.

If there is nothing wrong with it, the cause could be:

F32 (for condensing units only)

The problem is in the fan speed. The fan may not be connected correctly or the plugs may be loose. But you may have to replace the fan.

F33 (only for Vaillant turboTEC)

Half an hour after requesting heat, pressure switch does not close contact.

No signal from the gas-air relay.

F35, 36

Flue gases enter the boiler room.

Vaillant Turbomax plus Hot water problems.MOV

Occurs when duct or vents are closed.

  • Bad draught (weather conditions, short pipe);
  • Poor ventilation;
  • The room where the boiler is standing is too hot;
  • The boiler is too close to the wall.

Voltage on the eBus is too low. Can be caused by a short circuit in the busbar or a busbar overload.

Control signal to the valves is disturbed. The malfunction may be:

Vaillant boiler electronic board 0020092371

The gas valve has the wrong delay time. Occurs if the flame burns for more than 4 seconds after turning off the gas supply. Causes:

Overheating of the electronics unit. Overheating can come from the outside. t.е. The temperature in the room is too high. Or the block is faulty.

GFA error. The electronics or the ionisation electrode is defective. You should also check the integrity of the wires.


Each Vaillant boiler has a diagnostic system included in the electronic unit. The status of the unit is displayed on the LCD screen as a code (e.g., “low temperature”). ч. and past mistakes).

  • All inlet and outlet connections should be checked for tightness (this includes carbon monoxide, condensate and DHW drains).
  • Check the vacuum chamber for debris.
  • Check all electrical connections: check whether connectors and plugs are tight.
  • Check the condensate drain and siphon for salt and lime deposits. If necessary. clean.

Inspect the gas burner. it is most often clogged with carbon deposits. It is also necessary to clean the inside walls of the working chamber and the chimney. In the gas equipment is not very much soot, so that the user will not have much trouble.

What to do with error F20 on Vaillant gas boiler

The diagnostic function of the heating systems in automatic mode allows the user to solve almost all problems arising without calling the service. For gas boilers Vaillant error f20. is a rare phenomenon. If you understand what causes it, it is easy to identify the problem and fix it by your own efforts.

Deciphering of the code

Recommendations for troubleshooting of error f20 Vaillant, found on forums, thematic sites, are different. It appears when the boiler overheats, and there are several reasons for this. The nuance is that there are other codes in the manual for them: f0 (high temperature in the flow), f22 (sharp decrease of the coolant pressure) and several other codes.

Error f20 appears on the control panel of Vaillant boiler

Not everyone understands the difference between the sensors of Vaillant boiler. Devices installed on the direct line and return line monitor the current temperature. The thermostat switches on at a value of t˃ 95 0C at the outlet of the heat exchanger and shuts down the heating installation with an error signal f20. Consequently, this is what we need to deal with.

Step 1

Reset by pressing the button on the Vaillant control panel. Imported boilers are sensitive to supply voltage, and if the network is unstable, they fail with indication of any error. If it is false, it is easily reset.

Button8 “Troubleshooting” to reset specific faults

Step 2

Bring the thermostat into operating position. In Vaillant boilers it is “wound up” manually by pressing on the rod (colored red). If the error f20 is caused by a pump malfunction or other reason, it will disappear. To access the overtemperature thermostat you need to open the front panel. in most Vaillant models the safety device (fuse) is installed at the outlet of the heat exchanger, under the NTC sensor.

Location of NTC sensor of Vaillant boiler

Step 3. diagnose the signal circuits. Defects are determined visually: line breakage, melting of insulation, short circuit. causes of error f20 and emergency stop of Vaillant boiler. Check the reliability of contacts, the absence of oxides.

Step 4. testing the overtemperature sensor. Determine the serviceability is easy multimeter, by measuring the resistance. When the appliance contacts are closed, R = 0. Protective thermostat cannot be repaired. it must be replaced.

The last reason that causes error f20. electronic board of Vaillant boiler. It generates a fault code based on the signal from the overheat sensor. Independently identify the defect without schemes, experience, appropriate devices will not work. If the measures taken to eliminate error f20 are ineffective, you need to contact the service center. After replacing the circuit board, the boiler performance will be restored.

Advantages of self-diagnostic system

Gas heating units Vaillant are quite popular among owners of country houses and owners of apartments from old housing stock. Reliable boilers break down very rarely, they don’t cause inconvenience to their owners and don’t let the owners down during the heating season.

German company offers a domestic consumer a wide range of boilers of traditional and condensing types. There are floor-standing and wall-mounted models, atmospheric and turbine models with different capacities. The wide range of proposals allows you to choose the appropriate option by type of performance and capacity.

German manufacturer of boilers and water heating equipment offers a wide range of models for the organization of autonomous networks of heating and water supply

Among the trade offers of the supplier of reliable and productive equipment are atmospheric and turbocharged models, suitable for arrangement of houses, apartments, commercial and industrial facilities of different area

All units of a well-known German brand that has earned a reputation for impeccable appliances, equipped with systems that allow you to monitor the operating characteristics, to detect violations in a timely manner

The manufacturer thoroughly thought out multi-level security system of gas equipment operation. All components are included with the appliances to ensure a tight connection and flawless assembly

In the range presented to the consumer there are two-circuit and one-circuit boilers. Both variants can be complemented by tank water heaters with the same logo

Boilers of Vaillant production can be serviced and repaired only by the masters certified by the company. However, a number of maintenance and repair operations are available to owners

In the assembly of equipment for private boilers and water heating are used high quality components, but in case of violation of operating regulations, even they can break down

The code on the electronic display indicates that the boiler must be repaired or the error in operation must be corrected. In order to understand what is the matter, you need to know how to decipher the coding

A significant advantage of heating equipment from the German manufacturer is considered a self-diagnostic system. Simple in studying set of letters and numbers provides possibility to detect breaches in time and quickly correct the situation.

Let’s work together to understand the manufacturer’s coded clues and what you should do to restore the performance of the boiler.

Error warning levels

In order to detect malfunctions and monitor the condition of the gas boilers the manufacturer has developed a unique warning system. All information displayed on the unit is divided into two groups. The first of them is designed for owners who are not versed in the intricacies of gas economy, the second. for the masters of service.

Only Vaillant accredited service technicians are authorised to perform any repairs that require disassembly of the boiler drum

The principle of this division is justified by the level of the potential repair contractor. After all, not only the manufacturer of Vaillant boilers, but all his “associates” warn that not all repair operations can be performed by the owners of the units themselves. There are breakages, which should not be repaired by a do-it-yourself home handyman at all.

It is not even that after the intervention of an unauthorized craftsman, the warranty is automatically canceled. It is important that the gas equipment and fuel processed in it is explosive, toxic and fire hazardous if handled incorrectly. And the result of the repair made by an amateur can combine all of these risks, adding to them the damage to the neighbors.

Given the above reasons, the diagnostic system is divided into two parts. The first part is available to the owner of the boiler. Guided by the information encoded by the manufacturer, the owner can eliminate the malfunctioning of the equipment using the methods available to him.

To get the second level of information, you must enter a password that is known only to the service technician who maintains the equipment according to the contract signed before the installation

The second part of the coded information about the equipment errors is available only to gas service companies, with which the owner of the equipment must conclude a contract before installing the equipment. According to the contractual documentation is the delivery of fuel, monitoring of technical condition and performance of repairs.

To access the second part of the error data, the master of the gas service enters a password that is unknown to the owner. It would seem that the owner does not need information about these errors at all, since all operations behind this “barrier” are not available to him anyway.

To perform the repair actions relating to the second level of errors, the performer needs specialized knowledge, considerable experience and tools, which are unlikely to be found in the arsenal of a household handyman

But! Let’s remember how much money we have invested in the organization of heating. Let’s think about the fact that for the purchase, connection, installation has been paid a solid amount of money. And let’s make sure that all operations on restoring the unit operation are performed in accordance with the manufacturer’s instructions. Therefore, let’s find out what to do when the error code appears on the display.

How to monitor the condition of the equipment?

In order to get information about an imminent or already occurred malfunction, it is necessary to use diagnostic programs, indicated by programmers of the company in the menu by the range from P.0 to P.6.

The entry to the information system is as follows:

  • Find two buttons on the control panel. On one of them there should be an “i”, on the other one a “”.
  • Activate both buttons at the same time. Keep them pressed until “d” appears on the screen.0″.
  • Using the buttons with the ” ” and “-” signs we go through the list of faults to find the required item in the diagnosis. Confirm by pressing “i” button and get acquainted with the information displayed on the screen.

Heating systems for summer houses and country houses. Boilers, gas heaters, water heaters. Repair, service, operation. Mounting and installation recommendations.

Boiler Vaillant after 1 month of operation and gives out an error F75. What could happen?

If the unit displays error F75, then it is equipped with a pressure sensor. The instrument does not register any pressure rise when the pump is started. It is necessary to check the heating system as a whole, the presence of expansion tanks, the way of their connection. Perhaps this error is due to improper installation of the system.

I have a double circuit boiler Vaillant with the output of combustion products on the street. The problem is the following: when you turn on the hot water heating system failure occurs, the temperature drops and the unit does not heat the battery. After a complete reset the system works again. Honestly, I’m tired of resetting it.

The unit when the hot water is on goes into domestic hot water preparation mode, but at this time for heating it does not work. When you turn off the hot water, the unit starts heating the heating system. This is a normal working principle of the wall mounted dual circuit models with separate heat exchangers.

There is a boiler VU INT 240/2-3 R1. It stops periodically. The technicians came, looked at it, cleaned it. Changed the circuit board, but there is no result. It needs adequate diagnostics. So far, three specialists have not been able to find the cause of stoppages. Before that the unit has worked six years without problems.

For starters, see what light flashes when the machine stops. The fault indication will help you understand what the cause is. If the lights do not flash, it is impossible to make a prognosis.

Wall mounted condensing boiler Vaillant ekoTEC VU 656 E, gives error F28. Gas flows, exhaust is clean, cup is empty, ground is normal. When starting, the gas valve opens and then closes after 1 second, makes 3 such attempts and then gives an error.

F28 error can be caused by several reasons. Gas parameters not correct. Gas valve malfunction. Faulty automatics.

I have a problem with the wall mounted gas boiler Vaillant Turbo MAX plus int 282/2-5. It is single circuit, for DHW is connected to VIH R150 (new). It works fine for heating. When you turn on the water heating in the VIH, the temperature on the indicator quickly flies over 100 degrees, in the pump area there is a noise and beats, while the pressure indicator registers pressure jumps (from the set 1.5 atm to 2 atm). The burner immediately shuts down, the pump continues to work. After the drop in temperature (somewhere around 80 degrees) pump turns off, the unit switches to S54. Further, if the water heating mode is not switched off, everything repeats. An emergency shutdown with error F24 may occur. The heat exchanger is new. Changed it 3 days ago (before that the device did not want to work for heating. was switched off on S54). I changed the pump 3 months ago. The three-way switch is also new. What can cause this??

Usually, this behavior is caused by the inability to transfer power to the system (sediment on the heat exchanger due to poor fluid quality). If it was changed, it is possible that in other hydraulic groups of the unit there is a contamination.

I have a question about Atmovit series floor standing boiler Vaillant. After several years of use stopped seeing the flame, moved the board, the other one does not see either. It is clear that the problem is with the board. Is there a solution without replacing one??

For the decision of this problem it is necessary to diagnose the equipment. It is possible that replacing the circuit board is not necessary.

We have a Vaillant boiler. The temperature for the radiators is off, only the hot water supply works. Question: Why is the battery heating??

Most likely, the device gives out too much power to the heating system. This protects it from overheating.

I have a problem with a Vaillant turboTEC plus boiler. Hasn’t switched on all summer. When I turn it on, only the boiler heats. There is no circulation through the heating system. Pipes are not frozen. Water is coming from the radiator vent and system pressure is dropping.

Changed the pipe on the roof. Vaillant boiler shows error F29. What we have to do?

Check appliance grounding and gas distribution system.

Vaillant 242/5-3 runs for 5 minutes, then sharply gains temperature, there is a strong rumble, and shuts down. Lights up after a short period of time and then goes out again. What could be the reason?

Such operation may be caused by deposits on the heat exchanger. Deposits appear at use as the heat carrier mismatching on structure water or poor-quality antifreeze.

The problem: Two-circuit wall mounted boiler Vaillant turboTEC plus VU INT 242/3-5; works on water, without additives. Periodically “buzzes”. What is the cause of the noise?

Noise in the INT 242/3-5 can be caused by deposits on heat exchangers, pump or valve failure. It is also necessary to make a diagnosis of the heating system as a whole.

Boiler Vaillant. There is hot water in the sink in the bathroom, in the kitchen, in the bottom in the bathroom sink, but there is hot water in the shower mixer only at a small water pressure, if you turn on a stronger pressure, the water stops being hot, it is only in the shower mixer. And the unit also makes a lot of noise when something happens in it.

Secondary heat exchanger should be checked, it is likely to be very dirty. Also need to check the condition of the piping.

Who can tell, the boiler Vaillant 24 turbo old with green regulators. When reaching the set temperature begins to whistle and rattle in the secondary heat exchanger and pump. 3-way valve is intact, clean pump turns normally without loss of power. Heating and DHW is as it should be, only after using DHW can go into error.

The whistling can be caused by the wear of one of the gaskets in the hydraulic unit, the error may be due to overheating by inertia, in older models it can be caused by the slow operation of the three-way valve.

Gas 2-circuit wall mounted boiler Vaillant-24 in a private home works with water from the well. From time to time water comes with sand, although there is an inlet filter. Does it affect the operation of the boiler? What do you advise?

Typical problem of using well water. it is soft, but dirty. Mechanical contamination, of course, affects the work of the boiler, as it gradually clogs the built-in heat exchanger, and it ceases to heat water. A normal fabric filter lets in fine sand particles. Therefore it is necessary to install the cascade of cartridge filters to adjust the operation in D.H.W. mode.

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