What each sensor adds

Only the valve switch is required. Each sensor below is optional and adds one capability. Each zone can use a different combination.

What each one adds

• Valve switch (switch.*): required. It is the one thing ZoneFlow needs to water.
• Rain gauge tip counter (counter.* or sensor.*): rain credit, the dry-down hold and the rain stop. Without it, the zone waters as if it never rains.
• Outdoor temperature sensor: automatic hot and cool tiers, the ET curve, the deficit-mode heat guard, and the frost guard. Without it, the Fallback / Manual Temperature slider picks the tier — move it by hand for a heat wave or cold spell — and the frost guard falls back to a weather entity's current temperature if you have one.
• Soil-moisture probe (sensor.*, in %): dry soil waters early and wet soil skips. Without it, the modeled schedule decides alone.
• Pump power sensor: a per-pulse audit that the pump is really running. Without it, there is no low-power warning.
• Flow meter (cumulative volume): measured water per cycle and a "pump ran but no water moved" alert. Without it, there is no measured delivery and no no-flow check.
• Weather entity (weather.*) with forecast: holds off before forecast rain, with a dry-spell override. Without it, the forecast never blocks a run.
• Notify target (notify.*): phone alerts for faults and notable events, with per-zone notification levels. Without it, events go to the log only.

Sharing sensors between zones

Sensors can be shared between zones, for example one rain gauge or weather entity for the whole garden. The valve and a soil probe belong to one zone.

When a sensor misbehaves

• Temperature: a short dropout keeps using the last real days. After 3 days with no reading, the fallback slider decides until the sensor recovers.
• Rain gauge: unreadable values are ignored, not recorded as zero, and a counter reset or glitch does not lose rain already counted.
• Soil moisture: the schedule decides whenever the reading cannot be used, meaning offline, impossible (outside 0 to 100%), or a dry reading with no report for 24 hours. A wet reading is still trusted, since probes often sit at 100% in soaked soil. If wet readings hold watering back for twice the routine interval you get an alert, and if the probe has also stopped reporting, the schedule waters once and the check starts over.
• Pump power: you get a warning and the cycle still completes.
• Flow meter: the no-flow check is skipped rather than raising a false alarm.
• Weather: the forecast gate fails open and never blocks a run.