Why is my furnace only blowing warm air?
Check your thermostat’s settings, because your thermostat could be set to “Cool” which will limit your furnace from blowing hot air. Check that your air filter is clean and you don’t have a clogged air filter. Blocked air ducts can limit return air flow, which can compromise your furnace’s heat exchanger.
Why does the fan come on when the furnace is running?
When it’s in the “on” position, your fan will run continuously. When you switch it to “auto,” the fan will only come on while your furnace is running. The pilot light has gone out. If your older furnace blows cold air, it may have a pilot light that’s gone out.
Why does my furnace not ignite when I turn it on?
If the furnace is experiencing problems that could result in a fire, it may fail to ignite properly. Keep this in mind when the frustration hits. Here are other reasons your furnace may be short-cycling.
Is it normal to have cold air coming out of Your Fan?
It’s only a matter of time. Just as it takes a few seconds for the hot water to arrive when you turn on a tap, it’s completely normal to experience a few moments of cold air before you’ll feel any warmth coming out of your heating registers. You haven’t switched your fan setting to “auto.”
What’s the lowest temperature a furnace fan can run?
FAN-OFF: the lowest temperature setting (blue arrow, the left end of the dial) is the “FAN OFF” temperature. The FAN OFF setting lets the furnace blower continue to run for an interval after the furnace burner has turned off, but will shut the blower off after the heat exchanger has been cooled down to this temperature (usually 90 °F).
If the furnace is experiencing problems that could result in a fire, it may fail to ignite properly. Keep this in mind when the frustration hits. Here are other reasons your furnace may be short-cycling.
Why does my Furnace Fan blow cold air then heat?
Owner not a technician but understands mechanical/heating concepts. When heat called for and fan comes on it blows cold air, then heat, then cold, then off. It has always done this. Limit switch is at off 100, on 125 off 150. Changing set points on limit switch does not seem to change pattern. I do not dare force it.
What’s the difference between Furnace Fan on and fan off?
The FAN OFF setting lets the furnace blower continue to run for an interval after the furnace burner has turned off, but will shut the blower off after the heat exchanger has been cooled down to this temperature (usually 90 °F). FAN-ON: the middle setting on the fan limit switch dial (green arrow) is the “FAN ON” temperature.
FAN-OFF: the lowest temperature setting (blue arrow, the left end of the dial) is the “FAN OFF” temperature. The FAN OFF setting lets the furnace blower continue to run for an interval after the furnace burner has turned off, but will shut the blower off after the heat exchanger has been cooled down to this temperature (usually 90 °F).
