diff --git a/transfer_service/preprocessor.py b/transfer_service/preprocessor.py
index ffae00527058fbc366b1cbaaacbec3c3bb505254..9715af2b260f0af67272dd2b631c2b385ea50212 100644
--- a/transfer_service/preprocessor.py
+++ b/transfer_service/preprocessor.py
@@ -1,3 +1,5 @@
+import time
+
 from multiprocessing import Process
 
 from config import Config
@@ -11,9 +13,13 @@ class Preprocessor(Process):
         self.params = config.loadSection("scheduling")
         self.maxPendingJobs = self.params.getint("max_pending_jobs")
         self.maxReadyJobs = self.params.getint("max_ready_jobs")
+        self.execWaitTime = self.params.getint("exec_wait_time")
         self.pendingQueue = JobQueue("pending")
         self.readyQueue = JobQueue("ready")
         super(Preprocessor, self).__init__()
+        
+    def wait(self):
+        time.sleep(self.execWaitTime)
 
     def run(self):
         """
diff --git a/transfer_service/store_preprocessor.py b/transfer_service/store_preprocessor.py
index aa27be0fd13f8dd9c3e5379156b726c0291e7e11..9c6c20f63fdf65db8b8c0a29dad31ae0aa5032ea 100644
--- a/transfer_service/store_preprocessor.py
+++ b/transfer_service/store_preprocessor.py
@@ -7,9 +7,9 @@ import json
 import os
 import shutil
 import sys
-import time
 
 from datetime import datetime as dt
+
 from checksum import Checksum
 from file_grouper import FileGrouper
 from db_connector import DbConnector
@@ -169,7 +169,7 @@ class StorePreprocessor(Preprocessor):
         
     def run(self):
         while True:
-            time.sleep(10)
+            self.wait()
             if(self.readyQueue.len() <= self.maxReadyJobs and self.pendingQueue.len() > 0):
                 self.jobObj = self.pendingQueue.getJob()
                 self.username = self.jobObj["jobInfo"]["userName"]
@@ -177,7 +177,6 @@ class StorePreprocessor(Preprocessor):
                 self.execute()
                 self.pendingQueue.moveJobTo("ready")
                 print("Job MOVED!")
-            time.sleep(10)
 
 # Test
 #sp = StorePreprocessor()
diff --git a/transfer_service/vos_ts.conf b/transfer_service/vos_ts.conf
index d11956d20b06324547801a872c297a79bf2ee6b9..c2f99d5be3f182abcb3593e54faf9d326d26e1a8 100644
--- a/transfer_service/vos_ts.conf
+++ b/transfer_service/vos_ts.conf
@@ -43,7 +43,7 @@ port = 5672
 [checksum]
 ; suffix for files containing MD5 checksums
 md5_file_suffix = -md5sum.txt
-; buffer size in bytes when reading a chunk, default is 4096 B
+; buffer size in bytes when reading a chunk of data, default is 4096 B
 file_buffer_size = 4096
 
 [file_grouper]
@@ -57,6 +57,9 @@ max_dir_size = 100
 max_pending_jobs = 32
 ; maximum number of jobs within a 'ready' queue, default is 4
 max_ready_jobs = 4
+; minimum time interval in seconds between two consecutive checks on 
+; job queues (do NOT set to zero), default is 15 s
+exec_wait_time = 15
 
 
 ####################