diff --git a/modules/base_plugins/fermenter_hysteresis/__init__.py b/modules/base_plugins/fermenter_hysteresis/__init__.py
index 16cec75..f3d6efe 100644
--- a/modules/base_plugins/fermenter_hysteresis/__init__.py
+++ b/modules/base_plugins/fermenter_hysteresis/__init__.py
@@ -13,6 +13,7 @@ class Hysteresis(FermenterController):
 
         super(FermenterController, self).stop()
         self.heater_off()
+        self.cooler_off()
 
     def run(self):
         while self.is_running():