I use eggs right out of the refrigerator, large or extra-large (today's were AA Large, average 57 grams). I have also used room temperature eggs, and the difference was tiny. We can tweak for those variables.
The rack keeps the eggs at least a couple of centimeters above the water. This one has another tier so I can do up to a dozen eggs (actually fourteen) at a time. You can certainly jerry-rig something if you don’t have a rack. Keep the eggs vertical if you want them to be pretty.
Add 1 measured liter of cold water to the pan, put the rack in the pan, place the cold eggs on the rack, and set the cooker for 5 minutes at high pressure.
High pressure on the Instant Pot reaches 11.6 PSI. That’s lower than a standard pressure cooker (they run 15 psi), but it should be about the same as yours if it’s a similar type.
Now, this part's important regarding cracking: Time how long it takes your machine to warm up and start the clock. The warm-up should take at least about 8 minutes give or take a minute. You might even want to do this as a dry run with just the liter of water and tweak from there. If it takes significantly more or less time to heat up, that will affect your final result. So add more or less water as appropriate. You can also use warm or hot water, or add ice cubes to cold water to get that 8-minute warm-up time. If your cooker got to pressure significantly faster than that, that could totally have caused your cracking (see GdD’s answer).
Once it heats up, it’ll cook for five minutes.
After it cooks for 5 minutes (the Instant Pot beeps), let it sit without venting for five minutes. Time it carefully. That’s called a five-minute natural release.
While it’s doing its 5-minute natural release, prepare ice water for plunging the hot eggs. I use a pan with a lid for that. I’ll show you why in a moment.
Once the 5-minute natural release is over, vent the pot (if necessary to open) and immediately plunge the eggs into the ice water.
Let the eggs sit in the ice water for 5 minutes.
If you use a pan with a lid, now pour the water out and shake the eggs with each other and the ice. Peel. THIS is my favorite part of pressure-cooking eggs. Check this out, they just slip out of their shells.
Now, if you follow those instructions and they’re a bit overcooked or undercooked, adjust the natural release time. That you can control to the second. The 5-5-5 time routine has worked perfectly for me with cold, large eggs. If your eggs are extra-large, maybe add a minute to the natural release. If you start with room temperature eggs, subtract 30 seconds or so.
To illustrate how that works, check this out:
I forgot that egg after it cooked, and it stayed in the unopened cooker 26 minutes after the pressure cycle was done. See how dramatically overcooked it is? The natural release time gives you control.
This last egg went straight to venting/ice water (no natural release) after 4 minutes on high pressure, then opening the pot and plunging the eggs as quickly as possible:
I had never actually done that until tonight. That was yummy! An easily peelable, creamy, very soft-boiled egg.