Direct Vent Furnace Exhaust Smell

More than likely plugged secondary heat exchanger.

Direct vent furnace exhaust smell.

Had a case a few weeks ago same as you described. Clogged or otherwise unchanged air filters can also cause your furnace to smell musty. Homeowners carbon monoxide detector was going off. The condensing furnace produces condensed exhaust gases that contain water and carbon dioxide which together form carbonic acid that results in a corrosive condensate.

I would advise not using that furnace until its checked. Like the area around your outdoor intake system what s near your indoor vent registers can affect your furnace smells. Also known as the induced draft fan this one has a fan that is located on the end of the pipe. These cracks can eventually grow larger and ruin the furnace unless they are repaired early.

Do not inhale the exhaust fumes outdoors carbon monoxide levels will be extremely high there. The original oil fired boiler was replaced in 2015 with a utica boiler. The furnace uses an exhaust vent motor that pushes the exhaust gas through the vent pipe creating a positive static pressure in the vent. The oil ignition pressurizes the compartment and if there is a crack in the exchanger it can leak oil fumes out creating a smell.

The oil burner has a nozzle that sprays oil and then ignites it creating heat to warm the air. Taking care of the mess should resolve the smell as well. Check each vent register for a pet mess that needs cleaning. One of the most common vent contamination issues is the smell of pet hair or urine.

Musty odors can manifest themselves from dark and damp environments especially after long periods of inactivity. Just like the burning dust odor running your furnace for a few heating cycles will dry up any dampness and eliminate musty odors. It is a direct vent and the vent is located about 2 feet of the ground between 2 windows. Since the exhaust pipe is running on a sidewall the fan works together with the furnace.