420A44 Autotrol Black Cog for 118min 255-440 Time Clock (1030844)

The 420A44 is the black timer cog fitted inside the mechanical time clock of Autotrol 255 and 440 series control valves, setting the 118 minute cycle used to drive the valve through its regeneration sequence. It's a small but essential gear that meshes with the clock motor to advance the cam stack at the correct rate. If your softener's regeneration timing has started drifting or the valve is sticking mid-cycle, this cog from WrekinWater is often the fix.

Technical specifications

Symptoms that mean you need this part

• Regeneration timing has drifted and no longer matches the programmed cycle length
• The valve sticks or stalls partway through a regeneration cycle
• A grinding or skipping noise comes from the time clock motor as it tries to advance the cam stack
• The cog's teeth are visibly worn, chipped or stripped when the time clock cover is removed

Why it fails / why it matters

The time clock on 255 and 440 series Autotrol valves uses a gear train of small plastic cogs to step down the motor's rotation to the correct cycle speed, and the 420A44 sets the 118 minute timing used in that sequence. Plastic gear teeth wear gradually with every regeneration over years of service, and once a tooth chips or the cog slips on its shaft, the clock either advances too fast, too slow, or stalls altogether, taking the whole regeneration sequence out of step.

Why buy this from WrekinWater

WrekinWater stocks Autotrol time clock cogs and gears alongside the wider Pentair Fleck, Clack and Kinetico ranges, built up over 15 years trading from Bettisfield, Shropshire (UK Company No. 11000488) and more than 50,000 customers served. Orders are dispatched promptly and the business holds an Excellent Trustpilot rating, which matters when a stuck time clock is leaving a softener unable to regenerate.

How to fit it

1. Isolate the softener at the bypass and disconnect the transformer from the mains supply
2. Remove the time clock cover from the front of the control valve to expose the gear train
3. Note the position and orientation of the existing 420A44 cog before removing it from its spindle
4. Lift out the worn cog and check the meshing gears either side for wear before fitting the replacement
5. Press the new 420A44 cog onto its spindle, ensuring it meshes correctly with the adjacent gears
6. Refit the time clock cover, reconnect the transformer, and set the correct time of day before checking a manual regeneration cycles through smoothly