Yeah that s a lot of possibilities.
Furnace blowing cold air on heat setting.
So if you feel the air blowing out of the vents while the furnace is off the air will seem cool since it ll be at about room temperature.
When set to on the fan on your furnace will blow continually even when the furnace isn t actually heating the air.
Your furnace is overheating.
Your thermostat is set to on the pilot light is out.
Have an expert inspect your ducts along with the furnace.
The furnace has overheated.
Gas is not being supplied to the unit.
Your thermostat settings need to be adjusted.
A dirty air filter blocks airflow over the furnace s heat exchanger causing it to overheat.
If your furnace starts blowing warm but then quickly turns cold the flame sensor may need attention.
A furnace that is blowing cold air is most likely due to one of four possible causes.
For a heat pump or heater to produce warm air air must flow easily through the filter.
Your fan limit switch settings need to be adjusted.
Your furnace blowing cold air could be caused by hot air escaping through holes in the duct work that carries the heat throughout your building.
You have leaky air ducts.
Change the air filter a dirty air filter restricts airflow into your furnace.
Well if your furnace is blowing cold air it s most likely due to one of these problems.
Your furnace may be blowing cold air because the filter is too dirty.
2 clogged air filter.
Seems silly but you d be surprised how often this has happened.
What causes a furnace to blow cold air.
The thermostat is set to on if you notice your furnace is blowing hot air some of the time and cold the rest of the time your fan is most likely set to on when the.
When overheating your furnace can trip a high limit switch causing the furnace burners to shut off so that the heat exchanger does not crack.