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Richard, Technical Manager
Category: HVAC
Satisfied Customers: 1514
Experience:  27 years of Experience, NATE Certified, professional trainer
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I have a york furnace with an emerson 4702g board. When thermostat

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I have a york furnace with an emerson 4702g board. When thermostat is turned to cold, compressor comes on, 2 relay sounds are heard and nothing from the blower. The board flashes what seems like one flash over and over which says flame sensor?...I am confused. Any ideas?
hello you either have a failed board or something wrong in the flame sense circuit. So, look for the flame sensor it is near the burners ( thin metal rod) turn power off clean it with a scotch brite pad and make sure it is not touching anything. Next follow the wires that is attatched to it make sure water didnt get in a molex plug and is shorting it to ground. Then turn power back on and tell me what it does. Thank you Richard
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Customer: replied 5 years ago.

the flame sensor has been cleaned and the wiring appears fine. now the glow igniter is broken, do I need to repalce it first or is it not part of the circut?


Hello it is not part of the issue but you will need to replace it. It is most likey you have a bad board. The 1 flash code is probably an error in the board. Even with a Flame sense issue you should get blower and cooling. With solid state board all functions run through the board. You can get them on line for arounf 50 to 75 dollars typically