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1.0 INTRODUCTION
The Walchem WCT400 Series controllers offer conductivity and watermeter-based control of cooling
tower water, control of corrosion/scale inhibitor feed, and with the WCT410 models, control of two
biocide pumps. The inhibitor pump may be selected to operate in one of the following modes:
Feed and Bleed
Feed and Bleed with Lockout
Feed as a percent of Bleed
Feed as a percent of Time
Feed based on a Water Contactor input
Feed based on a Paddlewheel water meter input
The WCT series cooling tower controllers are supplied with a temperature compensated carbon
electrode with a cell constant of 1.0. The controllers are microprocessor driven industrial type with
on/off control outputs. A timed sample mode may be selected, and on small towers can reduce
installation costs by eliminating the need for a sampling bypass line. An optional isolated 4-20 mA
output that is proportional to the conductivity reading is available for all models.
Any set point may be viewed without interrupting control. Each set point change will take effect as soon
as it is entered. An access code is available to protect set point parameters, while still allowing settings
to be viewed.
The model WCT410 biocide outputs are scheduled on a user selectable 1, 2, or 4 week cycle. Each
biocide output is independent and may be programmed for one add per day. (in 1, 2 or 4 week cycle) or
up to 10 times per day (in daily cycle). It is possible to add both chemicals in the same day, however, as
a safeguard they will not occur at the same time. Biocide outputs may use independent pre-bleeds and
lockout times. All outputs are interlocked with a flow switch input.
An alarm relay is provided with WCT410 models. It is triggered by:
Low Conductivity reading
High Conductivity reading
No Flow situation
Bleed
Timeout
Sensor
Error
Temp
Error
Our unique USB feature provides the ability to upgrade the software in the controller to the latest
version.
An advanced USB capability option is available. The Config file feature allows you to save all the set
points from a controller onto a USB flash disk, and then import them into another controller, making the
programming of multiple controllers fast and easy. The data logging feature allows you to save the last
2 month’s readings and events to a USB flash disk.
