Sounds odd. If it's a fan flued boiler(and it sounds like it is) the thermostat must be functioning to bring the pilot gas on.
If it has an automatic ignitoin system, the pilot has to establish first and then stop sparking before the main flame solenoid gets power.
Unless iv'e mistaken the model the 100f has a small p.c.b to control the ignition phase. If it's the model i'm thinking of, if you turn the power off the pilot should shut down.
T.h.s
May 2007