diff --git a/src/lib/ebus/datatype.cpp b/src/lib/ebus/datatype.cpp
index 59b5cab2..3a3695bb 100755
--- a/src/lib/ebus/datatype.cpp
+++ b/src/lib/ebus/datatype.cpp
@@ -696,7 +696,7 @@ result_t NumberDataType::readSymbols(size_t offset, size_t length, const SymbolS
         }
       }
 #endif
-      if (isnan(val)) {
+      if (val!=val) { // !isnan(val)
         if (outputFormat & OF_JSON) {
           *output << "null";
         } else {