The building manager reported low pressure in one of the zones. After inspecting the riser room, I found that the main control valve was partially closed, restricting water flow. I verified this by comparing gauge readings and tracing the piping for any obstructions or leaks—none were found. Once I fully opened the valve, the pressure normalized across the system. I conducted a flow test to confirm proper operation and notified the building manager that the system is now functioning as intended.