diff --git a/custom_components/tahoma/climate_devices/atlantic_electrical_heater.py b/custom_components/tahoma/climate_devices/atlantic_electrical_heater.py
index cb8a5f8ae..4dc32e7a3 100644
--- a/custom_components/tahoma/climate_devices/atlantic_electrical_heater.py
+++ b/custom_components/tahoma/climate_devices/atlantic_electrical_heater.py
@@ -60,7 +60,7 @@ def supported_features(self) -> int:
     @property
     def hvac_mode(self) -> str:
         """Return hvac operation ie. heat, cool mode."""
-        return TAHOMA_TO_HVAC_MODES[self.select_state(*CORE_ON_OFF_STATE)]
+        return TAHOMA_TO_HVAC_MODES[self.select_state(CORE_ON_OFF_STATE)]
 
     @property
     def hvac_modes(self) -> List[str]: