I have a Balboa hot tub thats tripping the GFCI immediately. I unplugged motors and such to the circuit board. The only time it doesnt trip is if I remove the 20AMP input fuse. Its the orange one on the lower right in the picture. My board is similar but not exactly the same. Could a bad fuse itself trip the unit? If not what is on the ciruit protected by this fuse? Thanks

no a fuse won't trip gdci.
the fuse protects everything
i assume you disconnected the heater? this is your likely cause
if everything is disconnected and it trips, you may need to check that a frog or rodent isn't fried under the pcb
the transformer that plugs into the pcb could also be a cause

No, the fuse is not tripping the GFCI.

Have you also tried removing BOTH heater leads that are attached to the circuit board?


Woah- alacy posted just as I did- what great advice

Thanks for your replies, it was indeed the heater. So I'm off to that section...How to check and replace an element.