Technical Features and Development Trends of Fully Premixed Wall-Mounted Boilers

In recent years, thanks to favorable government policies on natural gas and growing public awareness of energy conservation and environmental protection, the wall-mounted boiler market has entered a period of rapid growth.
Condensing wall-mounted boilers stand out thanks to their eco-friendly advantages and have become the go-to choice for many households when it comes to winter heating needs! Now, let’s take a closer look at the technical features and future trends of fully pre-mixed wall-mounted boilers!
In past atmospheric combustion processes, excessive air entered the furnace (ratio = 1.2–2), resulting in only heat absorption and a decrease in thermal efficiency.
The water vapor in the flue gas condenses into condensate in the low-temperature section of the heat exchanger, releasing latent heat of vaporization and thereby improving the thermal efficiency of the heat exchanger. Moreover, compared to conventional atmospheric combustion, the amount of air entering the furnace chamber is significantly reduced.
The humidity of the residual flue gas is significantly reduced, and the condensation efficiency is markedly lowered. The thermal efficiency of the air-combustion condensing boiler is enhanced by wind-assisted combustion and intelligent control. The boiler employs mist control. Throughout the entire process, the combustion power remains constant. In the early stages of heating, the rated power can be used for heating. The airflow is regulated by both wind and intelligent control. The boiler is controlled by mist. Throughout the entire process, the combustion power remains constant. In the early stages of heating, the rated power can be used for heating.
Once the water temperature reaches the set point, the system automatically switches to low-power standby mode, achieving constant-temperature control. Thanks to intelligent control, the combustion output dynamically adjusts to match changes in water temperature, thereby eliminating gas wastage. This type of gas elimination and atmospheric pre-mixing combustion is also referred to as premixed combustion. The gas is injected from the nozzle, and as it exits the nozzle, it draws in air through the inlet section, resulting in partial mixing.
A portion of the primary air is ejected from the burner’s flame ports, drawing secondary air into the vicinity of the flame and enabling secondary combustion with the incompletely burned gases.
The flame length of primary and secondary combustion is relatively long, and the flame temperature is relatively low. If the heat exchanger is located nearby (about 130 mm away), the flame coming into contact with the heat exchanger will result in incomplete combustion.
The secondary air, generated by the replacement fan, creates a negative pressure within the combustion chamber, resulting in low thermal density. The heat exchanger facilitates heat exchange. Fifth, all preheating modes are inadequate. The combustion mode is unstable, and the combustion range is narrow. If the gas-to-air ratio is incorrect, ignition becomes extremely difficult. Therefore, to ensure the safe and stable operation of the appliance, all installation and adjustment personnel for pre-mixed wall-mounted boilers must possess professional installation and adjustment skills. Any backfire in pre-mixed combustion systems can lead to serious consequences, especially when using metal-fiber burners.
The burner consists of a pressure-reducing plate and an outer mesh. In the case of a drum burner with three pressure-reducing plates and an outer mesh, when tempering occurs, the gap between the pressure-reducing plate and the outer mesh plate may experience deflagration.
The metal fiber is positioned near the decompression plate, and an explosion occurs when the mixed gas passes through the tempering decompression plate. Therefore, when adjusting the combustion conditions, keep as far away from the tempering zone as possible. The choice of a wall-mounted boiler is crucial for its key components—the mixing unit. If the wrong component is selected, the entire appliance will fail to operate properly. The heat exchanger of a condensing wall-mounted boiler consists of a primary heat exchanger and a condensing heat exchanger. Similarly, the heat exchanger of a wall-mounted boiler comprises a primary heat exchanger and a condensing heat exchanger.
The best option is to combine the two approaches. This can help reduce heat loss and save costs. If you’d like to learn more about the technical features and development trends of fully premixed wall-mounted boilers, feel free to contact us anytime!