diff --git a/src/ol/pointer/touchsource.js b/src/ol/pointer/touchsource.js
index 1a78153f01..f5e4ea4377 100644
--- a/src/ol/pointer/touchsource.js
+++ b/src/ol/pointer/touchsource.js
@@ -156,6 +156,7 @@ ol.pointer.TouchSource.prototype.removePrimaryPointer_ = function(inPointer) {
  * @private
  */
 ol.pointer.TouchSource.prototype.resetClickCount_ = function() {
+  goog.asserts.assert(!goog.isDef(this.resetId_));
   this.resetId_ = goog.global.setTimeout(this.resetClickCountHandler_,
       ol.pointer.TouchSource.CLICK_COUNT_TIMEOUT);
 };