Yes, this type of set up won't work for just this reason. The timing cannot be extended. The intent of the use of the valve with the Osmolator is for a gravity feed, for example a reservoir above the tank. It is not for use directly with an RO which is extremely risky and not advised. If that valve sticks and it is more of a when rather than an if, you would likely wipe out your tank and have flooding and this goes for any type of solenoid and is not an issue of the quality of the valve. I think if you look at personal experiences in day to day life with machines, starter solenoids are usually the cause of failed starter on a car and modern front loading washers, the door latch solenoid is one of the main failures, you would see they are not something to trust with unlimited water. I would not use such a set up.
