diff --git a/custom_components/versatile_thermostat/underlyings.py b/custom_components/versatile_thermostat/underlyings.py
index a79a918..47f8bf5 100644
--- a/custom_components/versatile_thermostat/underlyings.py
+++ b/custom_components/versatile_thermostat/underlyings.py
@@ -1080,10 +1080,17 @@ class UnderlyingValveRegulation(UnderlyingValve):
             )
             return
 
-        # Send opening_degree
-        if 0 < self._percent_open < self._min_opening_degree:
-            self._percent_open = self._min_opening_degree
+        # Caclulate percent_open
+        if self._percent_open >= 1:
+            self._percent_open = round(
+                self._min_opening_degree
+                + (self._percent_open
+                   * (100 - self._min_opening_degree) / 100)
+                )
+        else:
+            self._percent_open = 0
 
+        # Send opening_degree
         await super().send_percent_open()
 
         # Send closing_degree if set
diff --git a/tests/test_overclimate_valve.py b/tests/test_overclimate_valve.py
index cbfcbd9..a29cd4c 100644
--- a/tests/test_overclimate_valve.py
+++ b/tests/test_overclimate_valve.py
@@ -627,11 +627,11 @@ async def test_over_climate_valve_multi_min_opening_degrees(
         assert mock_service_call.call_count == 6
         mock_service_call.assert_has_calls([
             # min is 60
-            call(domain='number', service='set_value', service_data={'value': 60}, target={'entity_id': 'number.mock_opening_degree1'}),
-            call(domain='number', service='set_value', service_data={'value': 40}, target={'entity_id': 'number.mock_closing_degree1'}),
+            call(domain='number', service='set_value', service_data={'value': 68}, target={'entity_id': 'number.mock_opening_degree1'}),
+            call(domain='number', service='set_value', service_data={'value': 32}, target={'entity_id': 'number.mock_closing_degree1'}),
             call(domain='number', service='set_value', service_data={'value': 3.0}, target={'entity_id': 'number.mock_offset_calibration1'}),
-            call(domain='number', service='set_value', service_data={'value': 70}, target={'entity_id': 'number.mock_opening_degree2'}),
-            call(domain='number', service='set_value', service_data={'value': 30}, target={'entity_id': 'number.mock_closing_degree2'}),
+            call(domain='number', service='set_value', service_data={'value': 76}, target={'entity_id': 'number.mock_opening_degree2'}),
+            call(domain='number', service='set_value', service_data={'value': 24}, target={'entity_id': 'number.mock_closing_degree2'}),
             call(domain='number', service='set_value', service_data={'value': 12}, target={'entity_id': 'number.mock_offset_calibration2'})
             ]
         )