diff --git a/homeassistant/components/maxcube/climate.py b/homeassistant/components/maxcube/climate.py
index da5a9f34dda..296da4f0ab4 100644
--- a/homeassistant/components/maxcube/climate.py
+++ b/homeassistant/components/maxcube/climate.py
@@ -171,8 +171,8 @@ class MaxCubeClimate(ClimateEntity):
         else:
             return None
 
-        # Assume heating when valve is open
-        if valve > 0:
+        # Assume heating when valve is open.
+        if valve:
             return HVACAction.HEATING
 
         return HVACAction.OFF if self.hvac_mode == HVACMode.OFF else HVACAction.IDLE