Autotrol 1235373 Module sensor photo interrupter - Optical Sensor

The 1235373 is the genuine-spec optical photo-interrupter sensor fitted inside the meter housing of Autotrol Logix and Performa control valves, reading the rotation of the turbine to tell the controller exactly how much water has passed through the softener or filter. It's the component that makes volumetric (demand-initiated) regeneration possible, converting turbine spin into the electrical pulses the controller counts. Anyone whose softener is regenerating on the wrong schedule, or not at all, after ruling out the meter turbine itself, needs this part, and WrekinWater stocks it as a fast, affordable fix.

Technical specifications

Symptoms that mean you need this part

• The softener no longer regenerates based on water usage, even though water is clearly being used
• The controller display shows zero or erratic flow when a tap is run
• Regeneration only happens on a forced or day-override cycle, never on demand
• The turbine meter itself spins freely and looks undamaged, but the controller isn't registering flow

Why it fails / why it matters

The 1235373 sensor works by shining an infrared beam through the meter turbine and counting how many times the beam is interrupted as the turbine's blades pass, translating that count into a precise volume figure the controller uses to schedule regeneration. The optical components inside the sensor degrade with age, and the sensor itself can be fouled by scale, sediment or biofilm carried in through the meter, or damaged by moisture ingress at the connector. Once the beam stops being interrupted cleanly, the controller either miscounts water usage or stops registering flow altogether, which on a volumetric system means regenerations happen too early, too late, or not at all.

Why buy this from WrekinWater

WrekinWater has been supplying genuine and genuine-spec Autotrol parts for over 15 years from its Bettisfield, Shropshire base, and as specialists in Pentair Fleck, Autotrol, Clack and Kinetico components it stocks the exact sensor your Logix or Performa controller needs rather than a generic substitute. With more than 50,000 customers served and an Excellent rating on Trustpilot, WrekinWater is a trusted source for the small, easily overlooked parts that keep a volumetric softener metering accurately.

How to fit it

1. Isolate the softener at the bypass valve before opening the meter housing
2. Locate the meter cap on the control valve inlet and remove the securing screws or clips
3. Withdraw the turbine and disconnect the lead from the existing optical sensor
4. Unclip the old sensor from its housing and note its orientation before removal
5. Fit the new 1235373 sensor into the housing in the same orientation and reconnect the lead
6. Refit the turbine and meter cap, restore the water supply, and run a manual flow test to confirm the controller registers usage correctly