Posted on May 24 2022
This article focuses on sensor assembly maintenance for top mount flush valves. The sensor assembly is also called the ‘head’ of a sensor flushometer. Top mount sensor flushometers are flushometers in the following series: ECOS, MC (metal cover), G2, and SOLIS.
For top mounted sensor flushometers, the majority of the maintenance completed is within the sensor assembly. This is why it is critical for the maintenance personnel who service these units to understand what components are in the sensor assembly, and when and how to troubleshoot those components.
The 4 models of top mounted sensor flushometers: ECOS, MC (metal cover), G2, and SOLIS.
The image above shows all of the major components of a top mount sensor flushometer. Those components are the sensor assembly, valve body, outlet coupling, flush connection (vacuum breaker), spud coupling, spud flange, tailpiece, stop coupling, control stop, and supply flange.
Sensor Assembly Components
As you see in the image above, all of the following components are located within the Sensor Assembly:
Button Cover Assembly with Screws (Single and Dual)
Lens Window Cover
Locking Ring Sensor Module
Cover Rest Plate
Solenoid
Inside Cover
How Top Mount Sensor Flushometers Function
How does a Sloan automatic flush valve work? When the sensor is activated on a water closet (meaning the sensor has detected a valid target), it will send a signal to the solenoid telling it to open. The solenoid will then pull in a plunger, and open a relief path for water from the upper chamber to go down through the flex tube of the diaphragm and through the valve to the fixture. This depressurizes the upper chamber and pressurizes the lower chamber, which causes the diaphragm assembly to rise. That allows the flush to occur.
The sensor then sends another signal to close the solenoid. This seals off the relief path. The upper chamber then slowly refills through the diaphragm bypass, which forces the flex tube diaphragm assembly back down and into the seat, shutting off the flush.
Troubleshooting Sloan Top Mount Sensor Units
What causes a Sloan sensor flushometer to not flush? Why does a Sloan sensor flush valve keep running? How do you fix an automatic toilet flush? Learn the answer to all of these questions and more for top mounted sensor flushometers in the various scenarios listed below, along with other troubleshooting tips.
Always troubleshoot from the top of the unit, down. Start with the cover assembly (including buttons) then consider the sensor module, then the solenoid assembly, then the diaphragm.
Troubleshooting issues are listed from most common to least common. So if the first solution listed doesn’t work, then consider the next cause and try the solution for that item, and so on.
Continuous Flush With No Shut-off
Cause - Solution
Debris is blocking the diaphragm bypass - Clean diaphragm to clear the bypass orifice
Debris is stuck underneath the diaphragm - Remove debris
Low pressure drop - Check facility or municipal line pressure
Diaphragm assembly compromised O-ring, cracked plastic guide (old) - Replace diaphragm assembly with proper GPF kit
Solenoid stuck open - Replace solenoid assembly EBV-136-A
Unit Is Not Flushing At All
First situation: No activation when the sensor is activated or the override button is depressed.
Cause - Solution
Override button damaged - Replace override button (3 different types)
Batteries are depleted - replace batteries
Sensor module is compromised - Replace sensor module
Solenoid is stuck closed - Replace solenoid assembly EBV-136-A
Second situation: Sensor does not activate, override button does activate
Cause - Solution
Sensor window is scratched - replace sensor window
Sensing malfunction - replace sensor module
Sensor Does Not Activate, Override Button Activates
For sensor activation issues, consider whether this issue has always occurred or not (since installation). If yes, then we need to look at the installation.
Cause - Solution
Rough-in too low, sensor is detecting front of toilet - Raise the supply or “elbow up” the stop, or reduce sensor range (older units that cannot self-adapt only)
Sensor not centered properly - Re-orient sensor until pointed straight forward
Reflection issue - Reduce sensor range (older units that cannot self-adapt only)
Rubber strip (wiper) missing from inside the cover - Contact Sloan Technical Support
No Evacuation When Flushed (either sensor or override button)
Cause - Solution
Low pressure - Address plumbing system deficiencies
Low consumption or urinal diaphragm installed in older closet - Install correct gpf diaphragm
Short flushing (perforated diaphragm) - Replace diaphragm
Locking ring not properly tightened (DFB - dual filter bypass diaphragm) - Tighten the locking ring
Water or Mineral Deposits Showing Underneath the Head of the Unit
Cause - Solution
Locking ring not tightened enough - Turn off water supply at stop, loosen and then re-tighten locking ring
Diaphragm Assembly compromised - Replace diaphragm assembly
Water leaking from threads above or below the locking ring
Cause - Solution
Solenoid leaking - Turn off water supply at stop, hand tighten solenoid or replace solenoid
Flush Duration is Randomly Normal, Long, or Short
Cause - Solution
Pressure fluctuation within the facility - Check plumbing system pressure and flow capacity
From Dominick, Sloan’s Senior Field & Technical Support Technician
Do not use pipe dope
Do not use Teflon tape
Tighten couplings and covers by hand, then “snug” with a wrench
Use a fixed smooth-jawed wrench
Avoid compression wrenches
Carry 100% silicone grease
Clean threads with a brass bristle brush
Wet the gaskets before installing
Clean with soap and water only
You will find the repair parts needed to service the units in this article on their repair parts pages listed below:
If you have any questions on Smart sensor flush valve. We will give the professional answers to your questions.