OK, I'll try to break it down for you. Bear with me, this is lengthy as it covers all the possible conditions:
The Apex processes the program once every second. On each pass, it evaluates all of the "Set" and "If" conditions. All of the "When", "Defer", and "Min Time" commands are only applied after the above conditions are evaluated.
Fallback OFF
Set OFF
If ATK_LO OPEN Then ON
If ATK_HI CLOSED Then OFF
When On > 005:00 Then OFF
Defer 000:10 Then ON
Defer 000:04 Then OFF
Min Time 060:00 Then OFF
For example, let's look at what it does when the water level is currently normal, and the PMUP is not running:
The lines of code in light gray color are not conditions that determine the desired output state.
Fallback OFF
Set OFF -- True <-- the last line that's True, so the output is Off
If ATK_LO OPEN Then ON -- False
If ATK_HI CLOSED Then OFF -- False
When On > 005:00 Then OFF
Defer 000:10 Then ON
Defer 000:04 Then OFF
Min Time 060:00 Then OFF
Now, let's say the water drops below the lower sensor for the first time:
Fallback OFF
Set OFF -- True
If ATK_LO OPEN Then ON -- True <-- the last line that's True, so the output wants to turn On, but has to wait for the Defer to complete its countdown
If ATK_HI CLOSED Then OFF -- False
When On > 005:00 Then OFF
Defer 000:10 Then ON <-- Starts counting down before allowing it to turn On
Defer 000:04 Then OFF
Min Time 060:00 Then OFF
If the water level happens to go back up and touch the ATK_LO sensor before the Defer timer expires, then the timer resets and we're back to the normal condition shown at the top of this post.
But if the water level remains below the ATK_LO sensor until the full 10 second Defer timer has reached zero, then the output turns On and the PMUP starts the flow of water. At this point, the When timer begins its 5 minute countdown while the PMUP is running. This timer is just acting as a failsafe in case the water level doesn't return to normal within 5 minutes. You should adjust this value based on the size of your tank, your normal amount of evaporation, and the time you'd consider normal to refill your tank. You only ever want this timer to be exceeded if something malfunctions, because it moves the output's dashboard slider from AUTO to OFF.
Fallback OFF
Set OFF -- True
If ATK_LO OPEN Then ON -- True <-- the last line that's True
If ATK_HI CLOSED Then OFF -- False
When On > 005:00 Then OFF <-- 5 minute safety countdown timer begins
Defer 000:10 Then ON <-- Countdown completed, output finally turns On
Defer 000:04 Then OFF
Min Time 060:00 Then OFF
Once the water fills back up to the ATK_LO sensor, the pump turns Off again:
Fallback OFF
Set OFF -- True <-- the last line that's True, so the output is Off
If ATK_LO OPEN Then ON -- False
If ATK_HI CLOSED Then OFF -- False
When On > 005:00 Then OFF
Defer 000:10 Then ON
Defer 000:04 Then OFF
Min Time 060:00 Then OFF <-- 60 minute countdown begins. The output cannot turn on again until expired, regardless of the water level.
The Min Time delay is designed to prevent the PMUP from running every minute or two. Instead, it waits 1 hour in between refill attempts. You can adjust this lower if you choose. I prefer 30 minutes on mine.
Let's say the water level drops again, but the Min Time 60 minute timer has not yet reached zero:
Fallback OFF
Set OFF -- True <-- the last line that's True, so the output is Off
If ATK_LO OPEN Then ON -- True <-- the last line that's True, so the output wants to turn On, but isn't allowed until the Min Time timer expires
If ATK_HI CLOSED Then OFF -- False
When On > 005:00 Then OFF
Defer 000:10 Then ON
Defer 000:04 Then OFF
Min Time 060:00 Then OFF <-- Timer still active, so the output cannot turn on
Once the Min Time reaches zero, the output turns On and the cycle starts all over again from the top:
Fallback OFF
Set OFF -- True
If ATK_LO OPEN Then ON -- True <-- the last line that's True, so the output wants to turn On, but has to wait for the Defer to complete its countdown
If ATK_HI CLOSED Then OFF -- False
When On > 005:00 Then OFF
Defer 000:10 Then ON <-- Starts counting down before allowing it to turn On
Defer 000:04 Then OFF
Min Time 060:00 Then OFF
I hope this clarifies it for you.
