Bosch Radiator Thermostat II - Valve Not Closing After 1-2 Days (Firmware 3.08.01) #1021
Description
Device Information
Model: RBSH-TRV0-ZB-EU (BTH-RA)
Product Name: BOSCH Radiator thermostat II
Firmware Version: 3.08.01
Firmware Date: 20250311 (March 11, 2025)
Hardware: BTH-RA
Zigbee2MQTT Integration: Yes
Batteries: New, recently replaced
Previous Behavior: Device worked correctly last heating season and at the beginning of current season
Problem Description
The thermostat valve fails to close properly after 1-2 days from successful calibration.
Symptoms:
Calibration completes successfully (status: calibration:success)
Device works correctly for 1-2 days
After 1-2 days, radiator remains hot even when:
Target temperature is set to minimum (5°C)
Valve position shows 0% (pi_heating_demand: 0)
System indicates valve should be closed
Physical observation confirms radiator is hot despite 0% valve opening indication
Steps Already Taken
✅ Battery replacement - Installed new batteries (no improvement)
✅ Firmware update - Already running latest available firmware (3.08.01 from 2025-03-11)
✅ Valve lubrication - Cleaned and lubricated valve stem with silicone grease
✅ Manual valve check - Valve stem moves smoothly when operated manually
✅ Re-calibration - Multiple calibration attempts performed
✅ Zigbee2MQTT configuration - Device properly paired and functioning
✅ OTA firmware check - Confirmed running latest available firmware from both:
https://github.com/Koenkk/zigbee-OTA
https://github.com/BoschSmartHome/bosch-smart-home-files
Observed Pattern
Day 0: Calibration successful → Valve operates correctly
Day 1: Valve still functions properly
Day 2-3: Valve fails to close despite 0% demand
Recalibration: Temporarily fixes issue, but problem returns after 1-2 days
Technical Details
The device appears to lose calibration over time. When reporting 0% valve opening (pi_heating_demand: 0), the physical valve remains open, causing the radiator to stay hot.
Current workaround: Manual recalibration every 2 days (not sustainable).
Is this a known firmware bug in version 3.08.01?
Are there any newer firmware versions in development that address this issue?
Is there any way to trigger automatic recalibration via Zigbee commands?
Could this be related to the April/June 2025 firmware updates mentioned in Bosch release notes that fixed "endless loop during auto-calibration"?
Related Information
According to Bosch Smart Home release notes:
April 2, 2025 release: "A fault has been resolved that caused the radiator thermostat to sometimes enter an endless loop during auto-calibration"
June 23, 2025 release: "New firmware for the radiator thermostat II [+M] with the new control algorithm"
However, firmware 3.08.01 (dated March 11, 2025) appears to predate these fixes.
Could you please confirm if firmware 3.08.01 has a known bug with valve calibration loss?
Thank you