Safety first: Immediately switch off the circuit breaker. Overcurrent conditions can cause fire.

Steps:

Check load rating: Compare the total wattage of connected heaters (e.g., electric underfloor mats, radiators) with the thermostat's rated current (e.g., 16 A at 230 V ≈ 3680 W). If the load is higher, you must use an external contactor or relay.
Inspect terminals: With power off, remove the thermostat and inspect all output terminals for discoloration, melted plastic, or loose screws. Tighten and re-terminate as needed.
Test each load: Disconnect individual heating circuits and test them one by one to identify a shorted element or actuator. Replace any component that trips the breaker or shows abnormally low resistance.
Reset and test: After correcting the load, restore power and clear the error by cycling power or following the manual. Monitor the thermostat for any unusual heating or smells.

Do not: Do not increase breaker size or bypass protection to stop E10; always reduce the load or use proper switching gear.

Thermostat shows E10 and heating cycles are blocked; app may show overcurrent or load error.

Possible Causes