The Walchem WDC400-525U controller is now obsolete and the closest equivalent is the WBL600 controller. The new WBL600 series has upgraded features; for reference, here is the description of the old model:
Dual condensate monitor, hardwired, cable glands, two isolated analog (4-20 mA) outputs, two standard electrodes (up to 250 psi), integrated datalogging and config file import/export via USB flash stick.