diff --git a/backup/util/progress/core_backup_progress.class.php b/backup/util/progress/core_backup_progress.class.php
index d4a5012075e..fcdd459e47b 100644
--- a/backup/util/progress/core_backup_progress.class.php
+++ b/backup/util/progress/core_backup_progress.class.php
@@ -31,9 +31,14 @@ abstract class core_backup_progress {
     const INDETERMINATE = -1;
 
     /**
+     * This value is set rather high to ensure there are no regressions from
+     * previous behaviour. For testing, it may be useful to set the
+     * frontendservertimeout config option to a lower value, such as 180
+     * seconds (default for some commercial products).
+     *
      * @var int The number of seconds that can pass without progress() calls.
      */
-    const TIME_LIMIT_WITHOUT_PROGRESS = 120;
+    const TIME_LIMIT_WITHOUT_PROGRESS = 3600;
 
     /**
      * @var int Time of last progress call.
@@ -202,7 +207,9 @@ abstract class core_backup_progress {
         // Update progress.
         $this->count++;
         $this->lastprogresstime = $now;
-        set_time_limit(self::TIME_LIMIT_WITHOUT_PROGRESS);
+
+        // Update time limit before next progress display.
+        core_php_time_limit::raise(self::TIME_LIMIT_WITHOUT_PROGRESS);
         $this->update_progress();
     }
 
diff --git a/backup/util/progress/tests/progress_test.php b/backup/util/progress/tests/progress_test.php
index 28f9f035ab3..0ba77486a47 100644
--- a/backup/util/progress/tests/progress_test.php
+++ b/backup/util/progress/tests/progress_test.php
@@ -56,9 +56,11 @@ class backup_progress_testcase extends basic_testcase {
 
         // Make some progress and check that the time limit gets added.
         $progress->step_time();
+        core_php_time_limit::get_and_clear_unit_test_data();
         $progress->progress(2);
         $this->assertTrue($progress->was_update_called());
-        $this->assertEquals(120, ini_get('max_execution_time'));
+        $this->assertEquals(array(core_backup_progress::TIME_LIMIT_WITHOUT_PROGRESS),
+                core_php_time_limit::get_and_clear_unit_test_data());
 
         // Check the new value.
         $this->assert_min_max(0.2, 0.2, $progress);