Danger: The Relay operates on mains voltage. Do not open the housing; only check external connections.

Test outlet: Plug another device (e.g., a lamp) into the same outlet to confirm it has power.
Check boiler feed: If the Relay is wired to the boiler, verify the boiler itself has power and that the Relay is connected to the correct terminals as per Netatmo instructions.
Try another outlet: For plug‑in Relays, test in a different known‑good outlet.
Inspect cord: Look for visible damage to the Relay’s power cord or plug. Do not use if damaged.

If the LED remains off with confirmed good power, the Relay’s internal power supply has likely failed; replace the Netatmo Relay.

Relay LED does not light at all when plugged in or powered from boiler.

Possible Causes