Corporate News
Technical Features and Development Trends of Fully Premixed Wall-Mounted Boilers
Release Date:
2022/05/25 10:15
In recent years, driven by 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 environmental advantages and have become the preferred choice for many households seeking winter heating. Now, let’s explore the technical features and future trends of fully premixed wall‑mounted boilers.
In conventional atmospheric combustion, excess air enters the furnace (excess air ratio of 1.2–2), resulting in incomplete fuel combustion and reduced thermal efficiency.
The water vapor in the flue gas condenses into condensate in the low-temperature section of the heat exchanger, releasing its latent heat of vaporization and thereby enhancing the heat exchanger’s thermal efficiency. Moreover, compared with conventional atmospheric combustion, the amount of air entering the furnace is significantly reduced.
The smoke humidity of the residual air is significantly reduced, and the condensation efficiency is markedly lowered. The thermal efficiency of the air‑combustion condensing boiler stems from its wind‑assisted combustion and intelligent control system. The furnace employs mist‑control technology, ensuring that the combustion power remains constant throughout the entire process. In the initial heating phase, rated power can be used for heating. The airflow is regulated by both wind and intelligent controls, while the furnace operates under mist‑control. Throughout the process, the combustion power remains unchanged, allowing rated power to be utilized during the early stages of heating.
Once the outlet water temperature reaches the set point, the system automatically switches to low‑power standby mode, ensuring constant‑temperature control. Thanks to intelligent control, the combustion output adjusts in response to changes in water temperature, thereby eliminating gas wastage. This type of gas‑elimination and atmospheric pre‑mixing combustion is also known as premixed combustion: the gas is ejected from the nozzle, while air is drawn in through the nozzle’s inlet section, achieving partial mixing.
A portion of the primary air–fuel mixture is ejected through the burner’s flame ports, drawing secondary air into the flame zone and enabling secondary combustion of the incompletely burned gases.
The flames from both primary and secondary combustion are relatively long, with lower flame temperatures. If the heat exchanger is positioned too close—approximately 130 mm—the flame may come into contact with it, leading to incomplete combustion.
Secondary air has a lower density due to the negative pressure in the fan‑replacement chamber during combustion. The heat exchanger facilitates heat exchange. Fifth, all preheating modes are subpar, combustion is unstable, and the combustion range is narrow. If the gas–air ratio is incorrect, ignition becomes extremely difficult. Therefore, to ensure the safe and stable operation of the equipment, installers and adjusters of all premix wall‑mounted boilers must possess professional installation and adjustment expertise. Backfiring in any premixed combustion system can lead to serious consequences, particularly when using metal‑fiber burners.
The burner consists of a pressure-reducing plate and an outer mesh. The rotary drum burner is equipped with three pressure-reducing plates and an outer mesh plate; during flashback, the gap between the pressure-reducing plate and the outer mesh plate may experience deflagration.
Metal fibers are positioned near the flashback arrestor, where an explosion occurs due to the mixed gases within the flashback arrestor. Therefore, when adjusting the combustion conditions, keep as far away from the flashback zone as possible. The choice of a wall‑mounted boiler is a critical component; selecting the wrong model can lead to system failure. In condensing wall‑mounted boilers, the heat exchanger consists of a primary heat exchanger and a condensing heat exchanger. Similarly, in wall‑mounted boilers, the heat exchanger comprises a primary heat exchanger and a condensing heat exchanger.
The best option is to combine the two. This approach reduces heat loss and lowers costs. For more information on the technical features and development trends of fully premixed wall‑mounted boilers, please feel free to contact us at any time!
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