Thermostat or TRV makes loud clicking, buzzing, or grinding noises during operation.

Safety: Allow radiators to cool before handling TRVs; isolate mains power if working near relay modules.

• Identify source: Listen closely to determine whether the noise comes from the thermostat, relay module, or TRV head.
• Check mounting: Tighten mounting screws on the thermostat and TRV. Ensure the TRV is firmly attached to the valve adapter.
• Recalibrate TRV: Run a valve calibration cycle to ensure the motor stops at the correct positions.
• Inspect relay module: If a relay is chattering, check for unstable control signals or incorrect wiring causing rapid on/off switching.
• Replace noisy component: If grinding or loud clicking persists, replace the TRV head or relay module as appropriate.