Covid-19 Update. We are in a low impact area and still shipping.



Mansfield Toilet Turns On And Off By It's Self

Click Here To Go To The Mansfield Model Number Guide

 

The fill valve is fine, it is just doing it's job.
A leaky flapper or seal is the most common cause.
The overflow replenish tube can be inserted beyond the water level causing a siphon.
A crack or hole in the flush valve can cause a slow leak.