diff --git a/tcs/htf_props.h b/tcs/htf_props.h
index 44842bb1f..8476036f3 100644
--- a/tcs/htf_props.h
+++ b/tcs/htf_props.h
@@ -43,7 +43,7 @@ class HTFProperties
 	HTFProperties();
 	
 	// The absolute value of these matter because we need to pass them in from SAM UI & cmods
-	enum {
+	enum E_HTF_PROPS {
 		Air = 1,
 		Stainless_AISI316,
 		Water_liquid,