diff --git a/src/ExitAirTempSensor.cpp b/src/ExitAirTempSensor.cpp
index 1cd55b8..c0aae42 100644
--- a/src/ExitAirTempSensor.cpp
+++ b/src/ExitAirTempSensor.cpp
@@ -1002,4 +1002,5 @@
     }
 
     io.run();
+    return 0;
 }