diff --git a/include/TachSensor.hpp b/include/TachSensor.hpp
index 567355b..c7c1b0e 100644
--- a/include/TachSensor.hpp
+++ b/include/TachSensor.hpp
@@ -83,7 +83,7 @@
     boost::asio::deadline_timer waitTimer;
     boost::asio::streambuf readBuf;
     std::string path;
-    int errCount;
+    size_t errCount;
     void setupRead(void);
     void handleResponse(const boost::system::error_code& err);
     void checkThresholds(void) override;