diff --git a/src/sampling/sampledSet/patchEdge/patchEdgeSet.C b/src/sampling/sampledSet/patchEdge/patchEdgeSet.C
index 69756b4769b74c259678da6caa392dad7a807373..6cf8f382b0d7b8321dff43c53a5143dae927d183 100644
--- a/src/sampling/sampledSet/patchEdge/patchEdgeSet.C
+++ b/src/sampling/sampledSet/patchEdge/patchEdgeSet.C
@@ -138,8 +138,9 @@ void Foam::patchEdgeSet::genSamples()
         origin_
     );
 
-    if (nMerged == 0)
+    if (nMerged == samplingPts.size())
     {
+        // Nothing merged
         setSamples
         (
             samplingPts,
diff --git a/src/sampling/sampledSet/patchEdge/patchEdgeSet.H b/src/sampling/sampledSet/patchEdge/patchEdgeSet.H
index eee1e664edc6e9c0e6125c3fb5425972e15caf55..7558bc69f7a9d81550098fcea2c9745c6a8628f3 100644
--- a/src/sampling/sampledSet/patchEdge/patchEdgeSet.H
+++ b/src/sampling/sampledSet/patchEdge/patchEdgeSet.H
@@ -94,8 +94,12 @@ Usage
     \endtable
 
 Note
-    The ordering of the points is according to the distance to the specified
+    - The ordering of the points is according to the distance to the specified
     origin.
+    - Collocated points get merged if closer than SMALL (1e-15 in double prec).
+    (hardcoded). Collocated points can occur if patch points are exactly
+    on the sampling plane. Note that (in parallel) any point merging gets
+    done locally before sending to the master.
 
 SourceFiles
     patchEdgeSet.C