[prndl]

When I activate the thermostat for the furnace the following occurs:

1) Fan starts and runs.
2) Gas turns on and igniter starts flame
3) After 30 seconds it clicks off. No flame. No fan.
4) The red light on control board flashes one time then no more
5) The black cylinder on the control board is buzzing/vibrating

A press of the reset switch by the control board starts it up again and repeats the sequence.

Sail switch is clean and functions correctly.
Gas pressure is correct.

What causes the black cylinder on the control board to vibrate? If it was trying to restart the flame it would click repeatedly not buzz/vibrate.