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[Madmak]

I would say ATO sensors screw up just as often as float valves. When is the last time your toilet tank violently overflowed? Even at city pressure 24/7.

The timer is the safety factor that keeps it from being a constant supply of pressurized water, and the timer is tuneable to meet your specific ATO needs, down to the minute if you wish.

I don't think twice about mine, even on 3 week vacations. A 100 GPD RO/DI can only make about 250ml of water per minute. If someone hasn't noticed that a sump or barrel is slowly filling over several days, eventually you will experience a spill of a few litres at most. Not really a big deal or risk IMO.