Place the split peas in a strainer and rinse with water. Place the strainer over a bowl and set aside for now, allowing the excess water drain out.
Press the saute button on your Instant Pot (IP) and heat up the inner pot for 2 minutes. Add the potato, onion, carrot and celery and saute for 3 minutes, stirring frequently and adding a splash of water when the veggies start to stick to the bottom of the pot.
Add the split peas, garlic, smoked paprika, salt and pepper and stir. Cook for about a minute and then add the water and stir one more time.
Turn the IP off and lock the lid into place, making sure the nozzle is in the sealing position. Using the Manual (or Pressure Cooking) mode, set the timer for 13 minutes. Use the natural release method when the timer goes off.
When all the pressure is out of the pot, carefully remove the lid and allow the Soup to cool for about 15 minutes, occasionally stirring to help it cool faster. After it has cooled, blend the Soup in batches with your blender (or all in one go with a blender stick) until creamy and smooth. Pour the soup back into the inner pot and stir in the parsley.
Let it cool completely before storing in the fridge.