Heating, Air Conditioning, Fridge, HVAC/York Natural Gas Furnace


I have a York Natural Gas Furnace Model #GF8100C16MU11C with 4 Burners.  The inducer motor will start and the ignitor will glow, three times, but no flames are produced, and then the blower comes on and blows cool air.  I have had the Pressure Switch and Gas Value Assembly replaced  this year and I am still having the same problem.  The heat was working today for a while, then it just started blowing cool air when i reduced the thermostat down to 73 degrees from 75 degrees. Sometimes, it will blow heat again if the furnace is left off overnight.  What is wrong with this thing?

Hi Lynne, Sounds like you have it narrowed down to the control board. The board should be blinking a trouble code, most likely a "flame failure". You should be able to see the LED through the sight glass on the bottom panel of the furnace. The codes will be located on the inside of the cover.

If the board is not flashing a code after it locks out the board is most likely bad. The only way to tell for sure is with a voltmeter.

Let me know what you find. JIM

Heating, Air Conditioning, Fridge, HVAC

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Jim S.


I can answer questions on gas or electric furnaces, ac units and heat pumps. I don't work on boilers,chillers,or home appliances.


I have been in the HVAC trade for over 35 years. For the past 15 years I have owned my own business. I am semi-retired so I can answer questions in a timely manner.

I attended trade school for 5 years on weekends and evenings. This was very hard to do, but well worth it!

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