Model: 8803RH

Function:

1. Core Control

    - Valve Regulation: Controls hot water flow to radiators/floor pipes based on room temperature vs. setpoint.  

   - Heating ON when room temp < setpoint; Valve closes when temp ≥ setpoint.

2.  Safety Protections  

    - High-Temp Cutoff (60°C): Auto-shuts valve if floor sensor ≥60°C.  

    - Sensor Failure: Displays  Err/ E1/ E2 and locks heating output.  

    - Frost Protection: Forces heating ON if room temp < user-defined threshold (e.g., 5°C).  

3. Programming Features

    - 5+2/7-Day Scheduling: 6 time periods per day, separate settings for weekdays/weekends.  

    - Economy Mode: Pre-set energy-saving temperatures for unused periods.  

4. Advanced Operations  

    - Key Lock**: Long-press ▲+▼ for 5s to enable/disable child lock.  

    - Floor Temp Display**: Long-press ▲ for 5s (dual-sensor models only).  

    - Advanced Settings**: Long-press Mode+Clock for 5s (off state) to configure:  

    - Frost protection threshold  

    - High-limit temperature (AL function)  

    - Sensor calibration  

5.  Technical Safeguards 

   - Low-Temp Auto-Start: Activates heating below user-set frost threshold.  

   - Post-Failure Recovery: Resumes operation only after fault clearance (e.g., sensor replacement).