As an efficient and energy-saving heating equipment, fully premixed condensing wall mounted boilers are widely used in households and commercial places. However, in the long-term use process, due to factors such as usage environment and maintenance frequency, fully premixed condensing wall mounted boilers are inevitably prone to various failures, which affect normal heating and living comfort. Understanding the common faults and corresponding solutions of fully premixed condensing wall mounted boilers can not only help users quickly restore equipment operation, but also extend the service life of fully premixed condensing wall mounted boilers and avoid additional maintenance costs caused by faults.

1、 Fault and solution of fully premixed condensing wall mounted boiler unable to start

The fully premixed condensing wall mounted boiler has no response and cannot start normally after being powered on, which is one of the common types of faults reported by users, mainly related to power connection, ignition system, and safety protection devices.

1. Power and circuit issues

Fault phenomenon: After connecting the power supply, the display screen of the wall mounted boiler does not light up, the button operation does not respond, and the equipment does not start at all.

Reason for malfunction: It may be due to poor contact of the power socket, damaged or broken power cord, or a blown fuse in the internal circuit of the wall mounted boiler, which prevents the equipment from receiving normal power supply.

Solution: First, check if the power socket is loose and replace it with another normal socket for testing; Next, check the appearance of the power cord. If there is any damage, replace it with the original power cord that meets the specifications in a timely manner; Finally, open the shell of the wall mounted boiler (power-off operation is required), check the internal fuse, and if it is blown, replace it with the same type of fuse. After replacement, confirm that there is no short circuit problem in the circuit before powering on.

2. Ignition system malfunction

Fault phenomenon: The power supply is normal, but the wall mounted boiler repeatedly attempts to ignite but fails, accompanied by a "dada" ignition sound or error prompt.

Reason for malfunction: The ignition needle position is offset, and there is too much carbon on the surface area, resulting in weak ignition sparks or inability to align with the gas nozzle; It could also be a malfunction of the gas proportional valve, which prevents normal gas supply, or a damaged ignition controller that cannot send ignition signals.

Solution: After power off, remove the combustion chamber cover plate of the wall mounted boiler, observe the position of the ignition needle, and if it is offset, use a tool to gently adjust it to align with the nozzle (with a spacing of about 3-5mm), and use fine sandpaper to polish the carbon scale on the surface of the ignition needle; If the ignition still cannot be started after adjustment, the power supply of the gas proportional valve should be checked. If the power supply is normal but there is no gas output, professional personnel should be contacted for maintenance or replacement of the proportional valve; If the ignition controller fails, the corresponding model of controller component needs to be replaced.

2、 Fault and solution of fully premixed condensing wall mounted boiler not heating up

When used in winter, the fully premixed condensing wall mounted boiler can be started but the heating effect is poor and the indoor temperature cannot meet the standard. It is necessary to investigate from three aspects: water circulation, heat exchange system, and parameter settings.

1. Blockage or poor exhaust of the water circulation system

Fault phenomenon: The wall mounted boiler produces loud noise during operation, uneven heat dissipation from radiators or underfloor heating, some areas are cold, and the outlet pipe temperature is low.

Reason for malfunction: After long-term use, scale and impurities accumulate in the pipeline, causing water circulation to be blocked; Or residual air in the system may cause air blockage, affecting the efficiency of water circulation.

Solution: First, turn off the power supply and inlet valve of the wall mounted boiler, open the system exhaust valve (usually at the top of the radiator or at the underfloor heating water collector), slowly exhaust the air until the exhaust valve continues to discharge water without bubbles; If the exhaust effect does not improve, it is necessary to check the built-in filter of the wall mounted boiler, remove the filter, and clean the impurities in the filter screen; When the pipeline scale is severe, it is necessary to use professional pipeline descaling agents for system cleaning, or contact a professional team for on-site cleaning.

2. Decreased heat exchange efficiency

Fault phenomenon: The wall mounted boiler has been running for a long time, but the water temperature rises slowly, and the exhaust temperature is abnormally high (the normal condensing exhaust temperature is about 40-60 ℃).

Reason for malfunction: The surface of the condensing heat exchanger of the fully premixed condensing wall mounted boiler is scaled or dusty, which hinders heat exchange; Or the mixture ratio of gas and air is imbalanced, resulting in insufficient combustion and a decrease in heat utilization efficiency.

Solution: After cutting off the power, remove the cover plate near the exhaust outlet of the wall mounted boiler and inspect the surface of the condensing heat exchanger. If there is dust, it can be blown clean with compressed air. If there is scale, it needs to be soaked and cleaned with a weakly acidic descaling agent (such as citric acid solution) (follow the equipment manual to avoid corroding the components); Check if the air intake is blocked, clean the impurities in the intake, and if the mixing ratio is unbalanced, professional personnel need to use specialized instruments to adjust the gas valve opening and fan speed to ensure that the gas and air are fully mixed.

3. Improper setting of operating parameters

Fault phenomenon: The wall mounted boiler starts normally, but the indoor temperature never reaches the set value or frequently starts and stops.

Reason for malfunction: The wall mounted boiler heating water temperature is set too low (such as below 50 ℃), which cannot meet the heat dissipation requirements; Or the indoor temperature controller is set too low, or there is a connection failure with the wall mounted boiler, causing the equipment to be unable to adjust its operating status according to the actual room temperature.

Solution: Adjust the heating water temperature appropriately through the wall mounted boiler display screen (it is recommended to set it at 40-55 ℃ for the underfloor heating system and 55-65 ℃ for the radiator system), and observe the indoor temperature changes; Check if the indoor temperature controller is powered on and if the set temperature is higher than the current room temperature. If the temperature controller is wired to the wall mounted boiler, check if the connection wire is loose. If the wireless temperature controller needs to be replaced with a battery or re paired to ensure normal signal transmission.

3、 Fault and solution of water leakage in fully premixed condensing wall mounted boiler

If there is water leakage in the fully premixed condensing wall mounted boiler, it needs to be dealt with immediately to avoid damaging the internal circuits and components. The main leakage points are concentrated in pipeline interfaces, valves, and heat exchangers.

1. Poor sealing of pipelines and interfaces

Fault phenomenon: There are water droplets seeping out from the bottom or connecting pipes of the wall mounted boiler, and in severe cases, water accumulation may occur, which may be accompanied by slight water seepage.

Reason for malfunction: The sealing rubber ring is aged or damaged during pipeline connection, or the interface screw is loose, causing water to seep out from the gap; It may also be due to aging and cracking of the pipeline material (especially plastic pipelines).

Solution: First, close the inlet and outlet valves of the wall mounted boiler, cut off the water source, dry the leaking area with a dry cloth, and observe the leaking point; If the interface screws are loose, use a wrench to tighten the screws appropriately (with moderate force to avoid damaging the threads); If the sealing gasket is aging, the interface components need to be removed and replaced with a new adapter gasket. Ensure that the gasket is in the correct position during installation; If the pipeline cracks, it needs to be replaced with a pipeline of the same specification. After replacement, it needs to be tested with water to confirm that there is no leakage before normal use.

2. Leakage of safety valve or exhaust valve

Fault phenomenon: The safety valve (usually located near the inlet) or exhaust valve of the wall mounted boiler continuously drips water, with a small but uninterrupted water volume.

Reason for malfunction: The water pressure in the system is too high (the normal water pressure of the fully premixed condensing wall mounted boiler is usually 0.1-0.3MPa), and the safety valve automatically releases pressure and discharges water; Or the wear of the safety valve core or the aging of the exhaust valve gasket may lead to seal failure.

Solution: First check the water pressure value on the wall mounted boiler display screen. If it is higher than 0.3MPa, open the system drain valve (or radiator drain valve) and slowly release some water until the water pressure drops to the normal range; If the water pressure is normal but still leaking, the safety valve needs to be checked. If there is a slight leakage, try repeatedly pressing the safety valve core to clean the impurities in the core. If the leakage continues, the safety valve needs to be replaced; If the exhaust valve leaks, the sealing gasket needs to be replaced or the exhaust valve component needs to be replaced directly.

4、 Fault and solution of error code in fully premixed condensing wall mounted boiler

The fully premixed condensing wall mounted boiler is equipped with a fault self check function. When an abnormality occurs, an error code will be displayed. Different codes correspond to different faults, which need to be checked in conjunction with the manual (the following are common code examples).

1. High temperature error (common codes such as E1, H1)

Fault phenomenon: The wall mounted boiler suddenly stops running, and the display screen shows a high temperature error code. Some equipment is accompanied by a buzzing alarm.

Reason for malfunction: Blockage of the water circulation system caused a sharp increase in water temperature, triggering high temperature protection; Or temperature sensor malfunction, false alarm of high temperature signal; It could also be a fan malfunction, causing poor smoke exhaust and resulting in excessive temperature inside the furnace.

Solution: Immediately turn off the power and cool down for 10-15 minutes. After the temperature drops, check the pipes and filters according to the method described in the previous section on "blockage of water circulation system"; If the error persists after power on, check if the temperature sensor wiring is loose, measure the sensor resistance with a multimeter (about 10k-50k Ω at normal room temperature, refer to equipment parameters for details), and replace the sensor if the resistance is abnormal; Check if the fan is running normally. If there is no movement or abnormal speed of the fan after power on, the fan motor needs to be repaired or replaced.

2. Wind pressure error (common codes such as E2, F2)

Fault phenomenon: When the wall mounted boiler is started, the fan runs, but then it stops and displays a wind pressure error code.

Reason for malfunction: Blockage and excessive bending of the smoke exhaust duct, resulting in increased smoke exhaust resistance; Or wind pressure switch malfunction, unable to detect normal wind pressure signal; It is also possible that the air inlet of the fan is blocked by dust and the air volume is insufficient.

Solution: Check if the outdoor exhaust outlet is blocked by debris (such as leaves or plastic bags), clean up the dust and foreign objects in the exhaust pipe, ensure that the exhaust pipe is installed straight, with no more than 3 bending angles, and the total length does not exceed the specified value of the equipment (usually no more than 5 meters); Remove the air inlet filter of the fan and clean the dust and impurities; If the above operation is ineffective, check the connection wire of the wind pressure switch. If the wiring is normal, use a nozzle to blow the wind pressure switch interface and observe whether it can be closed normally. If it cannot be closed, replace the wind pressure switch.

The troubleshooting of fully premixed condensing wall mounted boilers should follow the principle of "simple first, complex later, power off first, and operation later". In daily use, regular checks of water pressure, cleaning of filters, and maintaining smooth exhaust can effectively reduce the occurrence of faults. If encountering complex faults (such as core component damage or circuit failure), it is recommended not to disassemble them on your own. Contact qualified professional maintenance personnel in a timely manner to avoid equipment damage or safety hazards caused by improper operation. Mastering the common faults and solutions mentioned above can help users maintain fully premixed condensing wall mounted boilers more efficiently, ensure long-term stable operation of the equipment, and provide continuous and reliable heating guarantee for daily life.