This situation is obviously a manufacturer's fraud, which can be classified as cheating.

I suggest that I take evidence in an appropriate way before complaining to the relevant departments or local media.

If necessary, the wall-hung boiler can be removed and sent to the relevant authoritative third-party testing institutions for testing. Finally, if it turns out that the manufacturer cheated, the manufacturer should give some compensation and apologize.

However, this kind of engineering manufacturers dare to cheat, generally involving people from relevant local departments, which is more troublesome to deal with.