[Neidigs6]

My furnace is blowing out cold air. It was blinking twice then a long pause. I did the reset and it will blink normal than will go back to the 2 blinking light. It is dual heat.

 

[how]

Does it go back to blinking twice after the next ignition cycle.

The most common cause will be from a dirty flame rod that needs to be cleaned. Usually it will be located in the burner flame furthest from the igniter and will have a single wire attached to it. It will be held in place with a single sheet metal screw so it can be accessed and withdrawn without much fuss. Clean it with a fine grade steel wool or a scotch brite pad.

If it goes back to blinking twice before it tries to ignite, then let us know.

 

[Chimmy]

No a flame rod has never fixed anything in my experience

The flame sensor is a ground rod and is common to ground as is the pilot assembly, of course if its layered in carbon youhave more problems than just replacing it! the flame rod can be repplaced by grounding the pilot assembly to the ignition modules sense or grnd terminals internally they are common see the AC spark is rectified to a DC signal by the flame thus p[roving a pilot flame exists thus saying safe to go main burners! the flame is a poor conductor and will only send microamps of a C signal to the ignition module, the 2 lights are a pressure switch for the induced drat motor. and the orifices that the pressure switches tubing connects get blocked requiring reaming clear, the switches do fail as do the ignitotrs or modules the flame sensor is a rod and does nothing but sense a DC signal through the pilot flame.