diff --git a/src/ca/searchTimer.cpp b/src/ca/searchTimer.cpp
index db280f6e7..86b5dc924 100644
--- a/src/ca/searchTimer.cpp
+++ b/src/ca/searchTimer.cpp
@@ -149,8 +149,8 @@ void searchTimer::recomputeTimerPeriod (
     epicsGuard < udpMutex > & guard, const unsigned retryNew ) // X aCC 431
 {
     this->retry = retryNew;
-    unsigned idelay = 1u << tsMin ( this->retry,
-                                    (unsigned int) ( CHAR_BIT * sizeof ( idelay ) - 1u ) );
+    size_t idelay = 1u << tsMin ( (size_t) this->retry,
+                                    CHAR_BIT * sizeof ( idelay ) - 1u );
     double delayFactor = tsMax ( 
         this->iiu.roundTripDelayEstimate ( guard ) * 2.0, minSearchPeriod );
     this->period = idelay * delayFactor; /* sec */