You stated that you are currently using a mechanical timer. At the timer connections, wire your pump to the line side along with the wiring from the breaker. Wire your SWG to the load side of the timer. Set your vsp run times using the pump controller as it will be powered whenever the breaker is on. Set the timer to control the SWG; you can set the mechanical timer to come on a few minutes after the pump starts and a few minutes before the pump shuts down in case the clock for the timer and the vsp controller get slightly out of sync. As a backup, the SWG flow switch will prevent the SWG from powering up if the pump isn't running. Note: you will need to set your SWG to 230v as the pump is 230v as well.