Plumbing

BuildingWrench repair guide

Plumbing

Commercial Flushometer Won’t Flush: Beginner Troubleshooting Guide

A manual flushometer that will not flush usually has a closed or restricted control stop, a blocked handle/relief passage, worn internal parts, or insufficient building water pressure. Start with water supply and handle operation before opening the valve.

Last reviewed 2026-09-12 · General facility-maintenance information, not a substitute for site procedures, manufacturer instructions, codes, or qualified professional judgment.

Routine diagnosisSkill: BeginnerTypical time: 10–30 min
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Safety boundary

Isolate water before opening pressurized components and follow the manufacturer instructions for the exact fixture or valve.

Full troubleshooting steps are in Pro

The safety boundary, quick answer and stop-work conditions above stay free. Pro opens the likely causes, symptom table, step-by-step procedure and preventive maintenance for this guide.

Stop and call a licensed professional when

  • Multiple fixtures are affected
  • Control stop is seized or leaking
  • Supply piping is damaged
  • Valve body is cracked
  • Correct parts cannot be identified

Mistakes, FAQ, parts and tools

Pro opens the rest of this guide: common mistakes, field FAQ, the parts list, and the tools for the job.

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If a commercial toilet will not stop running, close the control stop first. The most common causes are debris in the flushometer, a restricted diaphragm bypass, damaged internal parts, or the wrong repair kit.