The Autotrol Blue "B" injector (part 1032971) is the genuine colour-coded injector nozzle for Autotrol 255-400 series water softener valves fitted with up to a 50-litre resin bed. Autotrol injectors are sized by colour rather than a single universal part, so searches for "Autotrol injector colour code" or "Autotrol 255 blue injector" land here — this is the Blue size specifically. Genuine Autotrol part, in stock at WrekinWater.
Technical specifications
| OEM part number | 1032971 |
| Colour code | Blue (B) |
| Compatible valves | Autotrol 255-400 series (155/255 400, 440, 460i) |
| Sizing basis | Resin bed volume — Blue covers up to 50L |
| Brand | Pentair / Autotrol |
Symptoms that mean you need this part
- Softening capacity quietly drops — water starts to feel hard sooner between regenerations, even though the valve is cycling on schedule
- The brine tank stays wetter than usual after a regeneration, or takes longer than normal to draw down
- A gurgling or popping noise during the brine draw stage that wasn't there before
Why it fails / why it matters
Every regeneration draws brine through this nozzle under pressure, which slowly erodes the throat and can also let fine sediment silt it up. Once the opening wears oversize or partially blocks, the injector under-draws salt — the valve completes its cycle normally so nothing looks obviously wrong, but the softener is quietly delivering less capacity than it should.
Why buy this from WrekinWater
Autotrol's colour-coded injector system trips a lot of people up — order the wrong colour and the softener will under- or over-draw brine. WrekinWater's team has been sizing these correctly for water treatment customers for 15+ years; if you're not sure which colour your 255-400 needs, contact us with your resin bed size before ordering and we'll confirm it. Rated Excellent on Trustpilot, UK stock.
How to fit it
- Confirm the colour/size code against your valve's resin volume before ordering — fitting the wrong size either starves or over-draws the brine system.
- Bypass the softener and relieve pressure via a manual regeneration step.
- Unscrew the injector cap and withdraw the old injector, noting its orientation.
- Fit the new injector the same way round, refit the cap, and return the valve to service.
- Run a manual regeneration and confirm the brine tank level drops by roughly the expected amount — this is your check that the draw rate is correct again.
Frequently Asked Questions
Unfortunately we are unable to accept returns on our Water Softener Parts So please confirm the correct part is ordered. If you have any doubt please feel free to call us prior to purchase for confirmation.
Blue B injector - Autotrol 255-400 Series 1032971 Injector Assembly with O-Rings Injector B - Blue
