IMI Maxseal ICO4-PST

The IMI Maxseal ICO4-PST is the first smart solenoid valve with fully integrated partial stroke testing.


Working closely with customers in the global oil and gas industry, we see the need for a no compromise solution for partial stroke testing.

Partial Stroke Testing (PST) involves moving an emergency shutdown valve part-way through its stroke, allowing the safety function to be tested without completely interrupting the process.

PST can improve safety in critical plants and extend intervals between expensive process shutdowns. Too often however, PST technologies are compromises that are difficult to install, complicated to operate and may even reduce the reliability of the emergency system.

The Maxseal ICO4S solenoid valve is the industry benchmark for critical applications in arduous environments. By incorporating advanced PST functionality within this ultra-reliable valve, we have created the new ICO4-PST. In doing so, we have avoided the compromises inherent in previously available technologies to create the safest, most reliable and easiest to use solution for partial stroke testing.


The ICO4-PST is the first fully integrated partial stroke testing solution with the control system built into the market leading IMI Maxseal ICO4 high integrity solenoid valve. With the lowest safe and dangerous failure rates of any intelligent PST system on the market and always providing the highest possible Diagnostic Coverage, the best possible SIL performance is guaranteed.

  • No dedicated PST device required therefore significantly reduces engineering requirements
  • High level diagnostics with position, pressure and time monitoring
  • Simple pass/fail reporting
  • Dual override mechanism eliminates possibility of over-stroke
  • Compatible with valve speeds from 2 to 120 seconds
  • SIL 3 certified as 1oo1
  • -40°C … +60°C
  • Local testing using HART 475 communicator, remote testing via HART

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