How to eliminate the problem of condensation water in the combustion chamber of wall mounted boilers

In the process of using a wall mounted boiler, if a pure low-temperature floor heating system is used and the heating area is relatively large, the return water temperature will be relatively low when the heating system is just starting to operate due to the large size of the system. The low-temperature water returning to the main heat exchanger of the wall mounted boiler will cause the surface temperature of the main heat exchanger to be too low. When the high-temperature flue gas containing a large amount of water vapor comes into contact with the main heat exchanger, condensed water will be generated, and the condensed water will form acidic substances with CO2 and SO2 in the flue gas, which will corrode the combustion chamber of the wall mounted boiler.

The first solution to this problem is the simplest, which is to install a bypass pipe through a three-way valve between the supply and return water pipes near the wall mounted boiler, so that a part of the heating hot water can directly return to the return water pipe to increase the return water temperature. However, the disadvantage of this solution is that the bypass pipe always has heating hot water returning to the return water pipe, causing a decrease in boiler efficiency. At the same time, as the return water temperature through the underfloor heating system gradually increases, it will cause the boiler return water temperature sensor to produce incorrect signals, thereby reducing the supply water temperature and affecting the effectiveness of the entire heating system.

The first and second options are to install a bypass pipe through a three-way valve between the supply and return water pipes near the wall mounted boiler, and to install a temperature control valve at the junction of the bypass pipe and the return water pipe. This way, when the return water temperature is relatively low, water will enter the return water pipe through the bypass pipe to increase the return water temperature. As the boiler runs for a longer period of time, when the return water temperature from the heating system gradually increases, the temperature control valve will gradually close. This can achieve both increasing the return water temperature and avoiding the problem of too much hot water directly returning to the return water pipe. The third option is to install a circulating water pump on the bypass pipe between the supply and return water pipes of the wall mounted boiler, and the operation of the circulating water pump is controlled by the return water temperature. This scheme mainly relies on the temperature probe on the return water pipeline to detect the temperature and control the operation of the circulating pump, which is reliable. The disadvantage is that the cost is relatively high, and it is mainly used for wall mounted boiler heating systems with high power.