I.D. Your Valve
Some water treatments units have a name to identify the manufacturer and some do not. Below is pictures of the most common valve used with no identifying name.
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Autotrol Timer 155
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Autotrol Timer 255
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Fleck 5600 Timer Valve
The 5600 timer has pins that can be set for 1,2,3,4,6 & 12 days between regenerations.
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Fleck 5600 Meter
The 5600 meter has a cable coming from the back that attaches to the dome in the rear of the valve.