My Kohler whirlpool started on its own with no water in it. We turned it off with the switch and it hasn't happened again. Is there a danger of it starting a fire if we are away from home and it does it again? What might have caused the problem?

We just experienced the exact same situation. Our whirlpool is brand new but it's in a spare bathroom and we hadn't used the tub in months. One day the whirlpool just started on its own with no water. I tried to shut it off my the on/off switch on the tub Sid wall, but it woukd shut off. I had to shut off the circuit breaker. It hasn't happened since and has worked perfectly when I reset the breaker and filled up the tub with water. My wife was sure she hadn't hit the switch by accident. Seems like there is an issue with some quirky switch problem.

Most Kohler tubs have a water sensor or water level sensor. Is this an air bath tub (holes in the floor)? or a jetted tub? If it is an air bath, the tub will purge after using it 15 to 30 minutes ater it is drained. If it is programable it will come on every 24 hours if it has been programmed. If it is a jetted tub, there may have been water on the sensor and caused it to start up. If it is a single on/off button the switch could have gotten water and caused it to start up, or there is a problem with the control box. It usually will not start a fire if it comes on, most of the newer pumps have run dry seals. If you leave the house for vacation or weekends, I would advise unplugging the tub or turning off the breaker.