The answer to 'why is my boiler smells bad' is that there are several common causes, including a buildup of sludge or debris, a faulty gas burner, or a leak in the system. The smell can indicate an issue that requires attention to prevent further problems.
Sludge and debris can accumulate over time, leading to a musty or rotten smell. This is often caused by a lack of maintenance and can be resolved by flushing the system. A faulty gas burner can also cause strange odors, as it may not be burning the fuel properly. Lastly, a leak in the boiler or the surrounding pipes can allow gases to escape, leading to a strong, unpleasant smell.