diff --git a/src/surfMesh/writers/surfaceWriter.C b/src/surfMesh/writers/surfaceWriter.C
index d910897c9deff92272b720185922134e95905631..2198ff13865c1b172e3c75c02bd5b69f8a100008 100644
--- a/src/surfMesh/writers/surfaceWriter.C
+++ b/src/surfMesh/writers/surfaceWriter.C
@@ -384,9 +384,11 @@ bool Foam::surfaceWriter::expire()
 
     upToDate_ = false;
     wroteGeom_ = false;
-    nFields_ = 0;
     merged_.clear();
 
+    // Field count (nFields_) is a different type of accounting
+    // and is unaffected by geometry changes
+
     return changed;
 }