Why does my furnace blow cold air sometimes.?

Question

I have my furnace set at 21 or 22 and most of the time it will stay around that temp, it usually goes down to 19 or so until it kicks back on. Sometimes though it goes down to like 15 and it still shows its calling for heat but it wont turn on. So I turn down till its below 15 then the heat display goes away and I turn it back up and it kicks on but sometimes only blows cold air for a minute then shuts off??? It -30 here so I do it again a few times till it blows hot air. Why is this. sometimes it also kicks off and on a few times and shuts off. Why please help

Answer 1

Just Like Genny Gum said.Also you better have you furnace checked out every year before it gets cold.If you
don't then get a carbon monoxide detector.The only other
thing to say is damm -30.Is that Fahrenheit or Celsius?
The temp here is 50 degrees Fahrenheit here in California.

Answer 2

Well for the most part. I could tell you how to do this But since I dont know what Unit you have Im gonna say this.
Have and Pay for a HVAC Tec to come out and do a check on it.
Maintiance is #1 on anything and if you dont do it then it will bite you in the butt.
There could be alot wrong from the therostat to the ing-sensor.
Units when they kick on they will blow hot air and the heat (FIRE) will shut off and the unit will still run for a few min- or so this is to help the heat exchanger cool down. If this did not happen then your unit would not last very long.
I Had this problem with a customer of mine just the other day and is was the thermostat. So Spend the money to have a check on your system. The better it runs the safer you are.
Goodluck

Answer 3

It would appear that when you set the furnace to 15, you are actually calling for cold air, or the thermostat senses that what you have set it for, temperature wise, has been reached, so it does nothing. Off hand, I would say that you need a new thermostat. The furnace is only going to turn off once it reaches the desired set point for temperature. Based on what you describe, the thermostat is not working properly, so you really need to replace it. You could do it yourself, I would, but you might prefer to have a heating and air conditioning company do it for you.

Answer 4

Your furnace is experiencing "soft lockouts" . Probably due to failed ignition sensing (Clean the flame sensor), or overheating (Change your filter, or make sure all of your supply registers are open). What you are doing is resetting the furnace by clearing the demand call for heat. Do you have LED's on the board ? If so, you can count the number of flashes, and determine the fault by reading your manual.

Answer 5

That's your high and low temp settings that are being used. They could be off. Turning your temp up and down like that doesn't help any energy problems you might have though. You should put it on one setting and leave it there. If everything is functioning O.K. then it should work right. If not, have someone come in and look at it.