gas boiler intermittent ignition. Replaced ignitor assembly 2 months ago after problem started. System sits in "idle state"-(pilot on,flue vents open,) System starts only after turning off and on master power switch,and switch on top of square ignition master module,and tapping on the side of it. If I don't tap,it won't start. The first 2 service techs I had showed me how to clean the ignitor,etc,and then cycled it off and on,and it worked. twenty minutes later,it did not.