The Walchem WCT410-1NNU controller is now obsolete and the closest equivalent is the WCT600PSNNN-NN controller. The new WCT600 series has upgraded features; for reference, here is the description of the old model:
Cooling tower controller -bleed & feed w/ 2 biocides and alarm, 120 VAC, prewired, no 4-20 mA output, no electrode, integrated datalogging and config file import/export via usb flash stick.