423,
Not sure I understand exactly how it works, but to run a 2-speed pump takes your pump filter relay plus one of the Aux relays configured to be used as part of the 2-speed pump control..
I would set up your automation so that the pump is running on low when it should not be running, and then locate the Aux relay being used for the 2-speed pump circuit and hit it with the plastic handle of a screw driver or something.. If the relay is hung up, this may jar it loose..
For your 2-speed pump to be running on low when it should be off, it means the aux relay is either being told to turn on, or the relay is bad.
Do you have a voltmeter?
Thanks,
Jim R.