Dunkirk Quantum 90 has power but won't start up

I decided to test out my 3 year old Dunkirk Quantum 90 to make sure it was ready for winter. I turned on one of the zones and everything started up like normal but quickly shut off like there was something blocking the intake. I checked and cleaned a small leaf out and tried again. This time nothing happens. The zone pump starts but the boiler won't do anything. The green power light is lit but that's it. What could be causing this?