Help! 20 year old Ruud 90 Plus condensing gas furnace with JCI G961DAJ-2401 controller keeps blowing its 24V AC 2 Amp fuse. I tightened the wires, nothing looks wrong.
I measured the current for each step:
mA Step 84 Start. No call for heat. 260 Draft induction motor on. 770 Gas valve open, flame on 880 Blower motor on 300 Gas valve closed 84 Blower motor off
I am measuring the current in series with the inline fuse from the 24V AC transformer on its way to the Johnson Controls controller board.
I'm stuck. Any ideas?