The pressure drops in the heating system wall-mounted boiler vailant reason

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

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

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

Diagnostics

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

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

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

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

What caused the malfunction

Chimney

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

Causes

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

Advice

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

Fan

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

Boiler fan vaillant

Differential relay

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

Pressure switch, impulse tube, Viessman boiler fan

Causes

• Clogged tubes leading to the sensor. Condensation, dust, soot narrow or block the channel. The draft is disrupted, the Vaillant boiler shows error f33. Disconnect, blow out, put in place, and the code will be cleared.

Clean the Protherm boiler tubes

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

Venturi tube

• Traction sensor . The device body is non-separable, but diagnostics of operation is simple. There is a membrane inside: the floor is displaced by the pressure of combustion products, pressing on the microswitch that closes the signal circuit. It is advisable to carry out a comprehensive performance check. Multimeter probes are connected to the terminals, and the input port of the differential relay is clamped with lips. When inhaling/exhaling, if the sensor is working properly, clicks are heard, and the tester readings (for resistance) change from ∞ to 0. The relay cannot be repaired and is rejected.

Advice

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

Share your experience

If you have experience in correcting error F33 in a Vaillant gas boiler, write in the comments to this article, we will try to consider your option and analyze it in detail in this or one of the following articles. You can also send photos and videos with comments and descriptions.

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Error codes for Vaillant boilers

So, what do the numbers on the monitor mean? Let's start with the most common malfunction of the Vailant gas boiler, which can cause panic in the owner when the boiler stops starting altogether.

Wall-mounted gas boilers Vaillant

Error F28

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

• Gas is not supplied due to a breakdown of the gas pressure reducer or meter.
• The gas is supersaturated with air.
• There is insufficient gas pressure (can be changed in the settings).
• The gas valve is closed (this also happens, check).
• The gas magnet has failed.
• Errors during installation and connection to the gas pipeline.
• Cable break.
• Failure in the ignition transformer.
• Carbon deposits on the electrode sensor.
• Damage to the control board.

F0 and F1

Problems in the NTC temperature sensor, in the first case on the supply, in the second - on the return. The problem may be either in the sensor itself or in the cable. It would be a good idea to check the plug on the electronic unit.

As a rule, when purchasing a high-quality boiler, the chance of breakdowns is very low, but it still exists. Ferroli boiler: device malfunction. Error codes and troubleshooting.

You can find out more about heat accumulators for heating boilers here.

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F2, F3, F4

The problem is with the NTC storage tank fill sensor. Loose insertion of the plug, faulty cable, loose connection to the housing. The sensor is faulty.

F5 (Atmo only)

Open circuit in the external traction sensor circuit. The reason may be:

• defect in the cable;
• incorrect sensor connection;
• a breakdown in the sensor itself.

F6 (Atmo only)

Open circuit of the internal traction sensor. Check the same as for error F5.

Electronic boiler panel Vaillant Atmo

F10/ F11

Short circuit in flow/return sensor. Check the sensor itself, the sensor plug, and the cable.

F13, F14

Short circuit in hot start sensor. The boiler can generate such an error if the temperature exceeds the threshold of 130 0C. Check: there is no short circuit in the plug to ground, a short circuit in the cable harness, and the functionality of the sensor itself.

F15/F16 (only for Atmo)

Short circuit of external/internal draft sensor. Check the serviceability of the sensor, cable, plug.

F20

Overheat protection, STB sensor. The boiler does not turn off due to a malfunction or poor connection of the supply temperature sensor.

F22

Dry work. You may just need to add water to the system. But the problem may also be in automation.

Need to check:

• water pressure sensor;
• reliability of connections between the pump cable and the water pressure sensor;
• pump performance: it could be jammed.
• or there is not enough pump power.
• The electronic board is faulty.

F23

Not enough coolant. You can check by comparing the temperatures in the return and supply lines - normally the difference should be small.

The connection between the supply and return outputs may be mixed up. But if the boiler was connected correctly and worked for a long time, then the problem is in the pump. It may be blocked or failed for other reasons. The problem may also be in the sensor or board.

F24

Not enough coolant. The temperature on the serve is off the charts. The actions are similar to the previous error:

• add water;
• check the pump and its cable;
• corresponding sensor and board.

F25

The temperature of the flue gases goes off scale, causing an emergency shutdown. Need to check:

• plug connection;
• temperature sensor;
• cables for damage.

F27

The valve is closed, but the automation “sees” the flame. This may be a malfunction in the flame sensor, or a malfunction of the magnetic valves. There is also a malfunction of the electronic board.

F29

In operating mode the flame goes out. Attempts to ignite fail. You need to check the proper grounding of the device.

If everything is fine with him, the reason may be:

• gas system interruptions in gas supply;
• operation of the ignition transformer;
• flue gas recirculation.

F32 (only for condensing units)

The problem is the fan speed. Perhaps the fan is simply not connected correctly, or the plugs are loose. But you may have to replace the fan.

Also check the sensor, cable and board.

F33 (Vaillant turboTEC only)

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

There is no signal from the gas-air path relay.

F35, 36

Flue gases penetrate into the room where the boiler is located.
Occurs when the air duct or gas outlet is closed.

• poor traction (weather conditions, short pipe);
• poor ventilation;
• the room where the boiler is located is too hot;
• The boiler is too close to the wall.

F49

The eBus is undervolted. The reason may be a short circuit in the bus or an overload.

F61

The control signal to the valves is broken. The malfunction may be:

• in gas valves;
• in cable;
• in the electronic board.

Vaillant boiler electronic board 0020092371

F62

The gas valve has an incorrect shut-off delay time. Occurs if the flame burns for more than 4 seconds after the gas supply is turned off. Causes:

• the injectors or manifold are clogged;
• the valve allows gas to pass through;
• failure in the electronic board.

F65

Overheating of the electronics unit. Overheating can come from outside – i.e. The room temperature is too high. Or the unit is faulty.

F67

GFA operation error. Electronics or ionization electrode faulty. You also need to check the integrity of the wires.

F 70

The boiler version number is incorrect for the display and electronics. The error may occur after replacing the display and electronics at the same time, and the correct number was not entered.

Boilers from the Korean manufacturer Navien are famous for their reliability and durability. However, this technique can also sometimes fail. Navien boiler: malfunctions, as well as design features and elimination of some problems.

Why does a gas boiler go out? Read about the causes of the most common breakdown in this article.

F71

The feed sensor data does not change. Feed sensor malfunction.

F73

Low water pressure alarm. Either the sensor is faulty or there is a short circuit.

F74

Alarm about high water pressure (more than 4.5 bar). Short circuit or other malfunction in the water pressure sensor.

F75

The gas boiler pump is started, but the pressure does not change.

The problem could be:

• in the water pressure sensor;
• in the pump;
• air got into the heating;
• The expansion tank is not connected correctly.

Do not trust connecting the boiler to amateurs! Errors made during the initial setup will not be detected immediately, but will gradually disable the system elements. Ideally, annual maintenance should be carried out before each new heating season. The main components are disassembled, cleaned and lubricated.

It is especially important to pay attention to Vailant double-circuit gas boilers in terms of diagnosing faults. They have a double load, and they work without rest. Make sure that the joints are airtight so that there are no leaks.

Paying close attention to your equipment while it is in good working order will help you avoid breakdowns in the cold and costly repairs.

Error F.62 Vaillant boilers | Causes and solutions | SC TERMOGAZ 8(495)589-00-07

Error code F62 on the screen display of the Vailant gas boiler shows that the system has detected a delay in shutting off the gas fittings.

The gas valve controls the fuel supply, the valve opens and closes at the command of the control board. This is an essential component of the gas system, which provides proportional gas supply to the burner and is made in the form of an electromagnetic device. The gas valve design includes shut-off and control valves.

The error is aimed at preventing and identifying a malfunction of the gas valve, which may become stuck or stuck during operation. If the electronic board sees the burner flame 4 seconds after the command to close the gas valve is given, then error F62 appears.

First steps after error F62 appears

You need to make sure that error 62 of the Vailant boiler is not caused by an electronics failure as a result of interference or unstable electricity. To do this, the equipment is restarted by pressing the Reset button on the front panel ( read more about the features of error reset

We discussed various models of Vaillant boilers in the article “How to reset the Vaillant error”). It is advisable to check the voltage of the network or an autonomous generator (if using one), and make sure that the ground loop is reliable.

The quality of grounding is checked using a voltage tester or a regular indicator screwdriver on an unpainted part of the housing. The glow of the indicator indicates the presence of potential on the body, which may be caused by poor grounding of the boiler.

Checking the ionization sensor

The ionization sensor turns off the gas supply when there is no burner flame, preventing the room from filling with gas. All gas heating appliances are equipped with this device.