Place half of the lemon juice and 4 cups of the water into a large bowl. Use a paring knife to remove and discard the outer layer of the celery root, leaving only the white part. Cut it into 1 1/2-inch pieces. Add to the bowl and submerge to prevent browning. When all of the celery root has been cut, lift the pieces out of the lemon water and place into the inner pot. Add the remaining lemon juice, the remaining 1 cup of water, olive oil, dill, sugar, salt, and pepper and stir.
Secure the lid, ensuring that the steam release handle is in the Sealing position. Press the Pressure Cook button and set the cooking time for 0 minutes. When the cooking time is complete, press Cancel and turn the steam release handle to the Venting position to quickly release the pressure. Remove the lid.
HANDS-ON TIME: 9 Minutes, salad needs to chill for 3 hours
COOKING TIME: 0 Minutes
BUTTONS TO USE: Saute and Pressure Cook
RELEASE TYPE: Quick Release
ADVANCE PREP: May be made 2 days in advance