My spa uses a HQ3000 controller. The spa is about 8 years old. Just a few days ago the breaker (GFI) on the side of the unit triped. I tried to reset it but it tripped instantly. I'm a do it yourselfer so I started to pull the unit out. In doing so I tested the reset as I disconnected the ligts and pumps. When testing after disconnecting the main pump the breaker stayed in. When I re-connected the pump the breaker tripped instantly. I thought the pump motor was bad. I connected the motor to another 120vac source and the motor worked just fine both low and high speed. My question is why would the pump cause the GFI to trip? I hope there is enough info here to lead you to a probable cause.
Much appreciated.......

Be sure your thermostat is turned OFF, or even disconnect the heater element... then do it with the pump plugged in.

It's probably your element doing it because once your pump starts up, your heater wants to start heating too....

Give it a shot and let us know what happens...

Thanks

I followed your advice disconnecting the heater. The pumps work......I assume this means the heater is bad so I pulled it out and will buy one today from your parts dept. Thanks very much.
P.S. In pullung the heater I had to remove an sdjustable pressure switch. I did this without touching the adjustment wheel. Does this need to be recaliberated? If so can you guide me to success once more..

Yeah the gfci makes a pretty good troubleshooting device! It's always the fastest way to find a faulty element, (one that's cracked anyways).

Don't worry too much about the pressure switch. If the controller's more than 3-4 years old, you may want to replace that as well. It'll save you another pain in the rear later on. As far as the pressure adjustment goes, just note the setting (on the psi scale) that it's got and make a note of it somewhere inside the box with a marker or something. That way you'll always know what the factory specification was.