2 furnace overheated let s say your furnace blows hot air then cold air but then stops blowing any air at all after a.
Furnace blowing cold air no heat.
7 reasons your heater blows cold air ac blows hot air 1 dead batteries in thermostat.
Have an expert inspect your ducts along with the furnace.
Is the furnace s blower constantly running.
A furnace blowing cold air could be due to your thermostat.
Other causes of furnaces blowing cold air pilot light ignition problem.
2 clogged air filter.
Or the gas line isn t supplying enough gas to your furnace.
Your gas supply could be turned off.
A clogged filter will restrict air flow into your home.
3 pilot light is out if your gas furnace is only.
Again using occam s razor we can assume that the next likely culprit for your heater blowing cold air is your thermostat.
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.
Set the thermostat to heat and.
1 thermostat is set to on is your furnace blowing cold air only sometimes.
Check the thermostat and ensure it is set properly.
If your gas furnace is blowing cold air a number of factors could be to blame many of which you can address on your own without the immediate help of a service professional.
Your furnace may be blowing cold air because the filter is too dirty.
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.
Seems silly but you d be surprised how often this has happened.
Otherwise your electric heater or gas furnace will not turn on.
If your furnace seems to be blowing cold air it could be a problem with the ignition.
If you haven t been regularly checking and changing your air filter it s most likely extremely clogged.
Most furnaces also have a reset button that clears any issues that might cause the furnace to produce no heat.
To troubleshoot a misbehaving gas furnace start with the easiest explanations and solutions then work your way to the most complicated.
After ruling out all of the simple problems above the most likely cause of a furnace not blowing air is a problem with the blower fan itself which if you remember is the fan that circulates your house s air over the heated coils.
Ensure that your thermostat is set higher than the temperature in your home.