Nibal,
1.5 PSI = 10.34 KPa, so it looks like your units might be off, or that equipment was added/imported using the wrong units set from your Preference Set, possibly? You could try making sure your units are good in the drawing, then check the Preference Set flow/pressure units to ensure they match. Then use the Replace option on that equipment and add it back to your project, ensuring the proper pressure is picked, then resize your zones to see if this corrects your issue. From here, sending your files in a tech support ticket will help us determine whether or not this is a bug or improper workflow, thanks!