Weak flush, or the toilet flushes by itself (sensor flushometers)

What this error means

Two documented Sloan facts: a weak or short flush usually means the WRONG diaphragm kit is installed — kits are matched to flush volume (GPF), and a low-consumption kit in a conventional fixture starves the flush — or supply pressure is low (Sloan flags below ~25 psi). And ghost flushing on sensor models is a RANGE problem, not a haunting: the sensor is set too far out and detecting the stall door or reflections; Sloan documents adjusting range via the override button. Dying batteries cause failure-to-flush, not phantom flushes — the low-battery signature is the red LED flashing 4 times when someone steps in range.

Symptoms

• Weak or short flush after a 'repair' (wrong kit)
• Toilet flushing with nobody there
• Red LED flashing 4x at users (batteries)

Try this first (safe DIY steps)

1. Ghost flushing: reduce the sensor range per the model's guide; check for reflective surfaces or a swinging door in the beam
2. 4-blink LED: replace the batteries (four AA on common Sloan sensor valves; ~3-year life)
3. Weak flush: check the valve's GPF label against the installed kit — mismatch = replace with the right kit
4. Whole-restroom weak flushing = pressure problem, not valves

Safety: power off before any physical intervention. Never bypass covers or interlocks — fuser areas run hot enough to burn.

When to call a technician

Building-wide pressure issues and concealed-valve work go to the plumber; range, batteries, and kits are in-house jobs.