A timer regenerates on a schedule whether the resin needs it or not; a metered valve counts gallons and regenerates when the capacity is used.
The difference
Penn State Extension: timed models regenerate on a set schedule and 'will waste more water and salt because they regenerate whether the resin needs it or not'; demand-control models regenerate after so many gallons.
| Timer | Metered | |
|---|---|---|
| Triggers | Days | Gallons |
| Salt and water use | Higher when use varies | Lower |
| Setup | Days between regenerations | Hardness and capacity |
Heads we cover
Replacement heads: Fleck 5600 Metered Control Valve, Fleck 5600SXT Metered Control Valve, AFWFilters Fleck 5600 Timer Control Valve.
Setting either one
Enter hardness plus about 4 gpg per ppm of iron on a metered valve; on a timer, set the days from the regeneration calculator.
Products mentioned

Fleck 5600 Metered Control Valve
Metered control valve · Fleck 5600

Fleck 5600SXT Metered Control Valve
Metered control valve · Fleck 5600 SXT

AFWFilters Fleck 5600 Timer Control Valve
Timer control valve · Fleck 5600