Sonoff TRVZB Anti-calcification (CA) - Firmware-based or automation necessary?

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Hi everyone,

I’m using the Sonoff TRVZB with ZHA (Home Assistant 2026.1.0) and the Versatile Thermostat (vtherm) integration.

The manual states that the device performs a routine calcium removal operation (“CA”) every Monday at 12:00 AM.

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Link to the manual

My questions:

  1. Is this function “hardcoded” into the firmware, or does it require an external trigger from HA?
  2. How does the device know the time? Does ZHA automatically sync the local time to the TRV?
  3. Since I’m using Versatile Thermostat: Does this integration interfere with the internal anti-calc program, or should I let the TRV handle it?

Firmware version: 0x00001401

Thanks for your help!