diff --git a/lib/services/header/index.js b/lib/services/header/index.js
index bce9440b..5a586919 100644
--- a/lib/services/header/index.js
+++ b/lib/services/header/index.js
@@ -532,7 +532,9 @@ HeaderService.prototype._onHeadersSave = function(callback) {
     return callback();
   }
 
-  clearInterval(self._syncCheckInterval); //SZ: clear the interval check as sync is completed
+  //SZ: clear the interval check as sync is completed
+  if(self._syncCheckInterval)
+    clearInterval(self._syncCheckInterval); 
 
   self._endHeaderSubscription(); // we don't need headers any more
   self._startBlockSubscription(); // we need new blocks coming tu us aynchronuously
@@ -714,13 +716,20 @@ HeaderService.prototype._startSync = function() {
       log.info('Header Service: Gathering: ' + numNeeded + ' ' + 'header(s) from the peer-to-peer network.');
       
       //SZ: Adding interval check for sync with peer is responsive or not
-      self._syncUnresponsive = true;
-      self._syncCheckInterval = setInterval(() => {
-        if(self._syncUnresponsive)
-          self._sync();
-        else //reset unresponsive as true
-          self._syncUnresponsive = true;
-      }, SYNC_CHECK_INTERVAL);
+      //(only if fcoin is started by flocore)
+      if(self._p2p._bcoin){
+        self._syncUnresponsive = true;
+        self._syncCheckInterval = setInterval(() => {
+          //check the best height
+          if(self._bestHeight < self._p2p._bcoin._bcoin.pool.chain.height)
+              self._bestHeight = self._p2p._bcoin._bcoin.pool.chain.height;
+          //call sync again if unresponsive
+          if(self._syncUnresponsive)
+            self._sync();
+          else //reset unresponsive as true
+            self._syncUnresponsive = true;
+        }, SYNC_CHECK_INTERVAL);
+      }      
 
       return self._sync();
     }