E8 error and thermostat cannot control or detect smart radiator valves (SRVs) in the system.

Safety: SRVs are typically battery powered and low voltage; mains isolation is not required but be cautious when working near radiators.

• Step 1 – Check SRV power:
  • Verify that each Protherm-compatible smart radiator valve has fresh batteries.
  • Replace batteries if low.
• Step 2 – Re-pair valves:
  • Put each valve into pairing mode (refer to valve manual).
  • In the thermostat or app, start device discovery and assign valves to rooms.
• Step 3 – Improve signal:
  • Avoid placing valves behind thick covers or metal enclosures.
  • Ensure the thermostat or hub is centrally located.
• Step 4 – Firmware updates:
  • Update SRV firmware via app if supported.
• Step 5 – Replace faulty valves:
  • If specific valves never connect, replace the affected smart radiator valve.