diff --git a/Framework/Beamline/src/DetectorInfo.cpp b/Framework/Beamline/src/DetectorInfo.cpp
index 4272744abb17d6877d55fe5bacead6f7cd1a9c75..8651a3b68c15b9fc6f10f280a6237eb4b6b2c2e5 100644
--- a/Framework/Beamline/src/DetectorInfo.cpp
+++ b/Framework/Beamline/src/DetectorInfo.cpp
@@ -171,6 +171,7 @@ void failMerge(const std::string &what) {
  * ignored, i.e., no time index is added. */
 void DetectorInfo::merge(const DetectorInfo &other,
                          const std::vector<bool> &merge) {
+  checkSizes(other);
   for (size_t timeIndex = 0; timeIndex < other.scanCount(); ++timeIndex) {
     if (!merge[timeIndex])
       continue;