Irrigation valve

← Greenhouse Sensors (demo) · myco-notes/entities/irrigation-valve.md · 1 KB · edited 2026-11-14 · raw

The 24 V bed valves on the relay board: how they are switched, the 20-minute alert, manual override

Mentions mqtt-broker.md 1 alerting.md 1 runbook.md 1 2026-02-28-rb-8-relay-board-manual.md 1

Mentioned by greenhouse-a.md 1 greenhouse-b.md 1 mqtt-broker.md 1 2026-02-frost-night.md 1 backlog.md 1

History (2 recent changes)

d33cd9b 2026-02-28 · Source: RB-8 relay board manual; the valve note cites it
91150c3 2026-01-30 · Irrigation valves, switched over MQTT

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# Irrigation valve

24 V solenoid valves, one per bed, driven by a relay board that listens on `mqtt-broker.md`.

- A valve that stays open longer than 20 minutes raises an alert (`alerting.md`).
- Manual override: the switch on the relay box; see `runbook.md`.

## Why the schedule lives on the board (since 2026-02-28)
- The board keeps time for 72 hours without power, per `2026-02-28-rb-8-relay-board-manual.md` (not tested here yet). That is why the frost-night fix moved the schedule here.