diff --git a/sh/install_hotdisk.sh b/sh/install_hotdisk.sh
index dc652f8..be7737b 100644
--- a/sh/install_hotdisk.sh
+++ b/sh/install_hotdisk.sh
@@ -138,8 +138,7 @@ run_as_root tee "$TIMER_FILE" > /dev/null <<EOF
 [Unit]
 Description=Run HotDisk temperature check every minute
 [Timer]
-OnBootSec=1min
-OnUnitActiveSec=1min
+OnCalendar=*:0/1
 Persistent=true
 [Install]
 WantedBy=timers.target