420A43 Autotrol Black Cog for 118min 255-440 Time Clock (1031554)

The 420A43 is the black drive cog (OEM part 1031554) fitted inside the mechanical 118-minute time clock used on Autotrol 255/440 series control valves - the geared skipper-wheel timer found on older, non-electronic softeners rather than the 460i/460TC electronic controllers that later replaced it. Customers searching for an Autotrol 440 timer gear, softener timer cog, or 118 minute clock replacement need this exact black cog, as the equivalent white cog is used on the 59-minute version. Genuine OEM replacement, stocked by WrekinWater.

Technical specifications

Symptoms that mean you need this part

• Softener timer motor runs but the valve never advances through its regeneration cycle
• Regeneration stops partway through, or the skipper wheel fails to index correctly
• Grinding, clicking or slipping noises from the timer housing during a cycle
• Visible worn, chipped or stripped teeth on the black cog when the timer cover is removed

Why it fails / why it matters

The 118-minute mechanical timer on 255/440 valves drives the valve through each regeneration step - backwash, brine draw, rinse and refill - using a motor-turned cam and skipper wheel. The cogs in that gear train take constant load every time the softener regenerates, and after years of use the plastic teeth wear, chip or strip, causing the skipper wheel to stall or slip a step. Because these valves are now largely superseded by electronic 460i/460TC controls, a worn cog is usually the cheapest and quickest fix rather than replacing the whole timer assembly.

Why buy this from WrekinWater

WrekinWater has been supplying water softener spares from Bettisfield, Shropshire for 15 years and over 50,000 customers, stocking genuine Pentair Autotrol parts alongside Fleck, Clack and Kinetico components, so this cog arrives as the correct OEM 1031554 fitment rather than a generic substitute. With an Excellent Trustpilot rating and specialist knowledge of legacy Autotrol mechanical timers, WrekinWater is a reliable source for parts that have otherwise become hard to find.

How to fit it

1. Isolate the softener and switch off power to the control valve before opening the timer housing.
2. Remove the timer cover screws and lift away the cover to expose the gear train and skipper wheel.
3. Note the orientation of the existing black cog and any timing pins before removing it.
4. Ease the worn cog off its spindle, taking care not to disturb the meshing gears alongside it.
5. Fit the new 420A43 cog in the same orientation, ensuring the teeth mesh cleanly with the adjacent gear.
6. Refit the timer cover, restore power, and run a manual regeneration cycle to confirm smooth, correct indexing.