Why does the furnace smell resembling sulfer aka rotten eggs?
Answers: The gas company adds that sulfur smell to alert you of a gas outflow, shut off the principal supply line if you know how to, and send for your power company.
Theres is risk of carbon monoxide poisoning and even an explosion if you let it verbs to leak.
you may hold some sulfur deposits left somewhere contained by the system. Fuel oil have high level of sulfur into it . the exhaust emits sulfur deposits within the air when burns. plus own your fire box and chimney checked for cracks and install CO2 's meter in your house