diff --git a/src/data-managers/simulators-data-manager.js b/src/data-managers/simulators-data-manager.js
index f630d4f..d0f169b 100644
--- a/src/data-managers/simulators-data-manager.js
+++ b/src/data-managers/simulators-data-manager.js
@@ -11,6 +11,40 @@ import RestDataManager from './rest-data-manager';
 import RestAPI from '../api/rest-api';
 import AppDispatcher from '../app-dispatcher';
 
+function isRunning(simulator) {
+  // get path to nodes.json and simulator name
+  var path = simulator.endpoint.substring(0, simulator.endpoint.lastIndexOf('/'));
+  path += '/nodes.json';
+
+  var name = simulator.endpoint.substring(simulator.endpoint.lastIndexOf('/') + 1);
+
+  // send request
+  RestAPI.get('http://' + path).then(response => {
+    // check if simulator is running
+    simulator.running = false;
+
+    response.forEach(sim => {
+      if (sim.name === name) {
+        simulator.running = true;
+      }
+    });
+
+    AppDispatcher.dispatch({
+      type: 'simulators/running',
+      simulator: simulator,
+      running: simulator.running
+    });
+  }).catch(error => {
+    simulator.running = false;
+
+    AppDispatcher.dispatch({
+      type: 'simulators/running',
+      simulator: simulator,
+      running: simulator.running
+    });
+  });
+}
+
 class SimulatorsDataManager extends RestDataManager {
   constructor() {
     super('simulator', '/simulators', [ '_id', 'name', 'endpoint' ]);
@@ -18,76 +52,35 @@ class SimulatorsDataManager extends RestDataManager {
     this._timers = [];
   }
 
-  isRunning(simulator) {
-    // get path and name
-    var path = simulator.endpoint.substring(0, simulator.endpoint.lastIndexOf('/'));
-    path += '/nodes.json';
-
-    var name = simulator.endpoint.substring(simulator.endpoint.lastIndexOf('/') + 1);
-
-    // send request
-    RestAPI.get('http://' + path).then(response => {
-      // check if simulator is running
-      simulator.running = false;
-
-      response.forEach(sim => {
-        if (sim.name === name) {
-          // save properties
-          simulator.running = true;
-          //simulator.defaultTypes = sim.units;
-          //simulator.defaultLabels = sim.series;
-        }
-      });
-
-      AppDispatcher.dispatch({
-        type: 'simulators/running',
-        simulator: simulator,
-        running: simulator.running
-      });
-
-      // remove timer if needed
-      if (simulator.running) {
-        const index = this._timers.findIndex(timer => {
-          return timer.simulator === simulator._id;
-        });
-
-        if (index !== -1) {
-          clearInterval(this._timers[index].id);
-
-          console.log('stop interval ' + this._timers[index].id);
-
-          this._timers.splice(index, 1);
-        }
-      }
-    }).catch(error => {
-      //console.log(error);
-
-      simulator.running = false;
-
-      AppDispatcher.dispatch({
-        type: 'simulators/running',
-        simulator: simulator,
-        running: simulator.running
-      });
-
-      // check for existing timer
-      const timer = this._timers.find(element => {
-        return element.simulator === simulator._id;
-      });
-
-      if (timer == null) {
-        // add timer
-        var self = this;
-
-        const timerID = setInterval(function() {
-          self.isRunning(simulator);
-        }, 5000);
-
-        console.log('start interval ' + timerID);
-
-        this._timers.push({ id: timerID, simulator: simulator._id });
-      }
+  startRunningDetection(simulator) {
+    // check if timer is already running
+    const index = this._timers.findIndex(timer => {
+      return timer.simulator === simulator._id;
     });
+
+    if (index !== -1) {
+      return;
+    }
+
+    // do first request for fast response time
+    isRunning(simulator);
+
+    // start new timer
+    const timerID = setInterval(isRunning, 5000, simulator);
+    this._timers.push({ id: timerID, simulator: simulator._id });
+  }
+
+  stopRunningDetection(simulator) {
+    // remove timer
+    const index = this._timers.findIndex(timer => {
+      return timer.simulator === simulator._id;
+    });
+
+    if (index !== -1) {
+      // stop timer and delete from list
+      clearInterval(this._timers[index].id);
+      this._timers.splice(index, 1);
+    }
   }
 }
 
diff --git a/src/stores/simulator-store.js b/src/stores/simulator-store.js
index 501d9c5..2bf0971 100644
--- a/src/stores/simulator-store.js
+++ b/src/stores/simulator-store.js
@@ -16,16 +16,18 @@ class SimulatorStore extends ArrayStore {
   }
 
   reduce(state, action) {
+    var simulator;
+
     switch (action.type) {
       case 'simulators/loaded':
-      case 'simulators/is-running':
+      //case 'simulators/is-running':
         // get simulator running state
         if (Array.isArray(action.data)) {
           action.data.forEach((simulator) => {
-            SimulatorsDataManager.isRunning(simulator);
+            SimulatorsDataManager.startRunningDetection(simulator);
           });
         } else {
-          SimulatorsDataManager.isRunning(action.data);
+          SimulatorsDataManager.startRunningDetection(action.data);
         }
 
         return super.reduce(state, action);
@@ -33,9 +35,20 @@ class SimulatorStore extends ArrayStore {
       case 'simulators/running':
         return this.updateElements(state, [ action.simulator ]);
 
+      case 'simulatorData/opened':
+        // get simulator
+        simulator = state.find(element => {
+          return element._id === action.identifier;
+        });
+
+        // restart requesting again
+        SimulatorsDataManager.stopRunningDetection(simulator);
+
+        return state;
+
       case 'simulatorData/closed':
         // get simulator
-        var simulator = state.find(element => {
+        simulator = state.find(element => {
           return element._id === action.identifier;
         });
 
@@ -43,7 +56,7 @@ class SimulatorStore extends ArrayStore {
         simulator.running = false;
 
         // restart requesting again
-        SimulatorsDataManager.isRunning(simulator);
+        SimulatorsDataManager.startRunningDetection(simulator);
 
         return this.updateElements(state, [ simulator ]);