Zurn ZRK-C-3.5-OB Retroflush Sensor Kit 3.5 Gpf

Product Description

The ZURN ZRK-C-3.5-OB is a battery-powered retroflush sensor kit rated at 3.5 gallons per flush (GPF), designed to upgrade or restore automatic flushing capability on compatible flush valve bodies. The kit includes the sensor module and all components needed to convert or retrofit an existing manual or older automatic flush valve to battery-powered sensor operation. Licensed plumbers and commercial facility maintenance technicians typically install this kit in restroom fixture applications where touchless flushing is required or mandated.

This retroflush kit is suited for commercial and institutional restroom environments, including office buildings, schools, healthcare facilities, and public restrooms. It is intended for use with compatible Zurn flush valve bodies where a sensor-actuated, battery-powered conversion is the target configuration. The 3.5 GPF flow rate is appropriate for water closet applications in jurisdictions that permit this flush volume. Installation does not require hardwired electrical connections, making it viable for locations where line voltage is not available at the fixture.

Key Features

• 3.5 GPF flush volume for water closet applications
• Battery-powered operation eliminates the need for hardwired electrical supply at the valve
• Retroflush design allows sensor upgrade on existing compatible flush valve bodies
• Includes sensor module and associated power components as a complete kit
• Touchless sensor actuation supports hygiene requirements in commercial restrooms

Compatibility

Designed as an OEM-style retroflush sensor replacement kit for compatible Zurn battery-powered flush valve assemblies rated at 3.5 GPF. Refer to Zurn product documentation and the superseding part number 40265105 to confirm fitment with your specific valve body.

Installation Notes

Installation should be performed by a licensed plumber in accordance with applicable local plumbing codes and the IPC. Shut off the water supply to the flush valve and relieve line pressure before disassembling any valve components. Do not overtighten sensor module connections, as damage to the valve body or sensor housing may result. Battery compartment access and sensor alignment should be verified before returning the fixture to service.

Technical Specifications

• Flush Volume: 3.5 GPF
• Power Source: Battery
• Actuation Type: Sensor (touchless)
• Kit Type: Retroflush

Standard Information

• Brand: ZURN
• Manufacturer Part Number: ZRK-C-3.5-OB