1. If you are not already in the default screen, press the left arrow key (key 3) until the screen looks similar to the image below.

2. Press the enter key (key 8). The screen will now appear as the image below.

3. Press the down arrow key (key 6). The screen will now appear as the image below.

4. Press the right arrow key (key 5). The screen will now appear as the image below.

5. Press the down arrow key (key 6) three times. The screen will now appear as the image below.

6. Press the right arrow key (key 5). The screen will now appear as the image below.

7. Enter the desired time from the key pad (keys 2). Let's say we want to set the system to continue purging for a further 3 minutes no hours, no seconds, and no milliseconds. Press key 0 three times, press the 3 key. At this point we could press the enter key (key 8) so long as the rest of the unset numbers were at 0. Otherwise we keep pressing the 0 key until the remainder are set, and then press the enter key (key 8). This will return to the set delays menu as shown in step 6.

8. You can now press the left arrow key (key 3) until you have returned to the default screen as shown in step 1.