What causes the pressure relief device to operate?

PRD operation may be due to a blocked showerhead leading to excessive water build-up which could require cleaning or replacement of sprayplate (6.1), or a twisted/blocked flexible hose causing obstruction and necessitating replacement of damaged parts (6.2). Additionally, PRD may activate during the commissioning procedure if the showerhead remains attached (6.3), requiring careful follow-through of installation instructions.