A furnace flame sensor is a device that's found in the burner assembly of your home's furnace. This thin metal rod sits directly facing the furnace's flame stream, and it tells the furnace whether ignition has occurred once the gas valve has been opened. If the gas valve has been opened and the sensor fails to detect a flame, the furnace will automatically shut down.
1 Be sure the thermostat is set to the proper setting (Heat if you’re calling for heat and the temperature you want the room to be). If the thermostat was replaced recently, the new thermostat may either be the wrong type (it must be specifically a heat pump thermostat) or it may have been wired improperly. A mistakenly wired thermostat can fry electronic components, preventing the heat pump from working properly.
AC air handler buzzing sounds. Do you hear a buzzing sound when you turn on the thermostat? The only thing that comes on in the house when you turn on the thermostat is the fan relay and fan in the air handler or furnace. Try switching the thermostat HEAT/COOL switch to OFF. Then switch the fan switch from AUTO to ON. The fan (only) should come on. If the air handler makes a buzzing sound, it probably has a bad fan relay or, more likely, blower fan.
The cost to replace your entire unit is around $4,000. That expense can range from $2,500 to $5,900, depending on the type and brand of furnace you choose. Brands particularly have an impact on that price. A Goodman electric furnace, will only cost about $2,100 for the unit and labor. On the other hand, a Trane oil furnace may cost up to $9,000 all things considered. Our Furnace Installation Cost Guide can give you a better idea on both the general cost and the differences for brands like Amana, Bryant, Coleman, and others. The brand also plays into the repair cost for your furnace. Especially the prices of individual parts can change; a York heat exchanger, for example, can cost up to $1,900, while the same component from Heil will cost as little as $400.