diff --git a/mini-beieli-node.ino b/mini-beieli-node.ino
index 0ce8238..9b72ad8 100644
--- a/mini-beieli-node.ino
+++ b/mini-beieli-node.ino
@@ -698,10 +698,11 @@ void StartNewIteration() {
     }
   }
   uint32_t sleep_time_sec;
-  if ((wait_time + 2) < CATCFG_T_INTERVAL) {
-    sleep_time_sec = CATCFG_T_INTERVAL - wait_time - 2;
+  if (wait_time < CATCFG_T_INTERVAL) {
+    sleep_time_sec = CATCFG_T_INTERVAL - wait_time;
   } else {
-    sleep_time_sec = 0;
+    // minimal sleep time is 5 seconds
+    sleep_time_sec = 5;
   }
   if (!fUsbPower) {
     DoDeepSleep(sleep_time_sec);
@@ -711,7 +712,7 @@ void StartNewIteration() {
       startNewIterationCb);
   }
   else {
-    gCatena.SafePrintf("%010d - light sleep; os_setTimedCallback for startNewIterationCb in %d...\n", millis(), CATCFG_T_INTERVAL);
+    gCatena.SafePrintf("%010d - light sleep; os_setTimedCallback for startNewIterationCb in %d...\n", millis(), sleep_time_sec);
     os_setTimedCallback(
       &iterationJob,
       os_getTime() + sec2osticks(sleep_time_sec),