             interval: Config.RECEIVER_SESSION_PP_INTERVAL
         @_onHeartbeat "ping"
         @triggerTimer()
-        setInterval ( =>
+        @ppTimerId = setInterval ( =>
                 @_onHeartbeat "ping"
             ), Config.RECEIVER_SESSION_PP_INTERVAL
 

            if app and (app.getAppId() is @appId)
                app.terminate()
        @_clearTimer()
        @sessionManager.clearReceiverSession()
        @channel.close()


            throw new Error "cannot create a ReceiverSession with a null channel!!!"

        super sessionManager, token, appId
        @ppTimerId = null
        @timeout = Config.RECEIVER_SESSION_TIMEOUT
        @tag = "ReceiverSession"

