diff --git a/src/TachSensor.cpp b/src/TachSensor.cpp
index 70d7d4c..b42062c 100644
--- a/src/TachSensor.cpp
+++ b/src/TachSensor.cpp
@@ -114,7 +114,7 @@
                 std::getline(responseStream, response);
                 float nvalue = std::stof(response);
                 responseStream.clear();
-                if (!isnan(overriddenValue))
+                if (overridenState)
                 {
                     nvalue = overriddenValue;
                 }