I purchased two of these timers this season after two of the older model MisterTimer's gave up the ghost. Within a week, one day apart, both of the new MisterTimer's failed to turn off and flooded our front yard and then our back yard. I'm no expert, but based on my experience with fault tolerant systems, a failure of the valve should result in water NOT flowing. A failure that results in an open valve was a minor issue for us (aside from the cost of the timers) but under different circumstances it could have been a disaster. Based on the previous entries on this thread, it looks like there is a known problem and hopefully a solution. Any advice?