diff --git a/noptica.py b/noptica.py
index 75ed5e8..6116605 100644
--- a/noptica.py
+++ b/noptica.py
@@ -100,6 +100,7 @@ class InductionHeater:
         self.queue.put(amount, block=False)
 
     def stop(self):
+        self.queue.put(0.0, block=True)
         self.queue.put(None, block=True)
         self.thread.join()
         self.serial.close()