Question about Heating & Cooling
The furnace will turn on, the burner will light and then turn off 5-10 seconds later. It will do this three or four times and then shut down. If I go to the thermostat (it's an old style manual) turn it down then back up it will work properly only for that cycle. Once it shuts down after reaching temp. it goes back to not functioning properly again
A Make and Model number of the furnace not the thermostat will help but I can walk you thru the operation of a typical furnace. It sounds to me that the burners are igniting properly but the flame sensor is not sensing the flame and shutting down the system. You will need to find the sensor and clean it and check the wire from it to the control board. Typically, the flame sensor is found at one side or the other of the burner box. It is a small probe that the flame hits. Depending upon your model it may have a small wire attached to it leading back to the control. Or it may be part of your auto-pilot assembly. ? At any rate, you will need to get to it and very delicately brush it off. Then inspect the flame channel. This is a trough area where the flame travels to ignite all burners. Over time, they tend to fill with rust and debris. Take a small screwdriver and run the blade down the trough. Inspect the wire that goes from the flame sensor to the control board. Make sure it is not frayed or broken or shorting out and that the connection at the board is good.
Beyond that, it's time for a technician to come.
Let us know the Make and Model of the furnace (found inside the furnace cabinet) and maybe we can help you further.
Posted on Nov 20, 2007
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