Hello my name is Heath it will be my pleasure to assist you. If the tank ran out then you are going to have to bleed the fuel system. You will need a small empty can to catch fuel in that will fit under the bleeder screw on the right, a 3/8 box end wrench to loosen the bleeder screw. Hold the reset button down for 60 seconds and the gun should start loosen the bleeder screw till fuel and air start coming out let it bleed out till you have a full stream of fuel if the furnace shuts off try and tighten the bleeder screw quickly so no air gets sucked back into the fuel system then reset the furnace by holding the button in again and bleed air out again you may have to do it a few times till you get all the air out tightening the bleeder while the furnace is still running should get the furnace to fire up.
You may need to turn the power off then back on before holding the reset down.
This solution did not help nor was it attempted, we had to call a technician to come out and replace a nob.
Okay sorry I could not be of more assistance.