diff --git a/includes/rrdtool.inc.php b/includes/rrdtool.inc.php
index cb811f1f64..9161f84ddf 100644
--- a/includes/rrdtool.inc.php
+++ b/includes/rrdtool.inc.php
@@ -81,10 +81,10 @@ function rrdtool_close()
     /** @var Proc $rrd_async_process */
 
     if (rrdtool_running($rrd_sync_process)) {
-        $rrd_sync_process->sendCommand('quit');
+        $rrd_sync_process->close('quit');
     }
     if (rrdtool_running($rrd_async_process)) {
-        $rrd_async_process->sendCommand('quit');
+        $rrd_async_process->close('quit');
     }
 }