Is it the furnace or thermostat? Sometimes the blower is blowing on the furnace and its cool air coming out and at the same time you hear the pilot trying to kick on. After 3 or 4 times of the pilot trying, you hear it kick on and the heat start blowing hot air... and I have the thermostat sat at 73 degrees, but is reads that it is 70 degrees in the house and the furnace has not kicked on, so I have to keep playing with the thermostat turning it uo and down until it kicks on. Its like the thermostat and the furnace are not communicating, but why not?

Could be several reasons, is the thermostat new? Is the furnace new or old?

If you just installed a new thermostat, sometimes you have to set what is called the heat anticipator. Also you got to make sure every wire went into the correct spot when you switched it out. Also some thermostats have a set point for on and off, or it could say differential. Is it an electronic thermostat?

Its normal for the air not to be warm when the blower first starts up. Sometimes they also start up before the burners come on to make sure the air isn't stagnant.

No its not a new furnace or new thermostat. Both are least 5-8 yrs old. This problem just started in the last month. Yes the thermostat is electric.


could be several reasons, is the thermostat new? is the furnace new or old?

if you just installed a new thermostat, sometimes you have to set what is called the heat anticipator. also you gotta make sure every wire went into the correct spot when you switched it out. also some thermostats have a set point for on and off, or it could say differential. is it an electronic thermostat?

its normal for the air not to be warm when the blower first starts up. sometimes they also start up before the burners come on to make sure the air isnt stagnant.

Try cleaning the flame senser with emory cloth, fine sandpaper, or steel wool. Does your furnace have two green lights and one orange light on the control board? If it does, let us know what the lights are doing as the furnace cycles.

Where do I find the control board? And if inside the furnace do I need to turn the furnace off before accessing?

The control board will be behind the bottom door of furnace(if the furnace is a downflow) and behind the top door if the furnace is an upflow. Are there any view ports on the furnace covers? If there are, you can just look in through them and see the lights. Other wise, just remove both covers, and the blower door safety switch will kill power to furnace. Then hold the switch in with your hand and let me know if you see any lights, and what they are doing as the furnace tries to ignite.