Hardie TC-12B 'Master Valve' Indication: Replace Master Valve Solenoid

Inherited TC‑12B; Manual Start Does Nothing; Display Shows "Master Valve"

1. Manual link: Total Control 24 Manual.
2. "Master Valve" alert usually means the master valve solenoid is shorted.
3. Locate the master valve: downstream of the backflow preventer, before the first zone valve.
4. Replace its solenoid (shut off water, swap solenoid, reconnect wires, hand‑tighten). Cost ~$10, 15 min labor.