What is the reason why the warm air box of Dongfeng Tianlong 245 cab often breaks?

The heater water tank is installed in the heater housing (as shown below).

The heater is installed on the dashboard of the cab, and it won't break no matter what you do. All we know is that there was an accident and it broke down. Personally, I think that your water tank may be broken because you didn't install it properly, and there was a bump during driving, or the heating water pipe was broken, or it may be that the heating water tank you replaced was the cheapest deputy factory product.