The Walchem WECT400-1N1U controller is now obsolete and the closest equivalent is the WCT600 controller. The new WCT600 series has upgraded features; for reference, here is the description of the old model:
Cooling tower controller – bleed & feed, 120 VAC, prewired, no analog (4-20 mA) output, electrodeless conductivity sensor and tee, 20 ft cable (for inline mounting), data logging and configuration file capability.