An AUTOMATIC pH CONTROL SYSTEM shall be supplied for continuous monitoring of the pH level in water. The system shall be a CHEMTROL® 240 DIGITAL CONTROLLER of current design and production model manufactured by SANTA BARBARA CONTROL SYSTEMS of Santa Barbara, California or a technically equal system certified by the specifying agent as capable of providing equal performance for all operating functions.


1. The controller shall be microprocessor based and shall show a digital readout of pH values.  All instrumentation shall be enclosed in a watertight non-metallic cabinet with a clear window cover. All operating controls, calibration adjustments and safety alarm settings shall be accessible from the front panel.

2. The control system shall automatically activate a chemical feeder for an acid or alkaline solution in order to maintain the pH level within +/- 0.1 of the setpoint selected by the operator. Setpoint selection shall be by direct dialing on a scale calibrated in pH units.

3. The control system shall include the following feed modes: off, manual, automatic and proportional. The feed rate in the proportional zone shall be adjustable by the changing the bandwidth of the zone from 1% to 100% of the setpoint value.

4. The face panel shall feature an LED digital readout for pH units. Calibration of the pH display shall be adjustable from the front panel, using a standard chemical test kit for pH.

5. Audible, visual and remote alarms shall be activated by high/low pH conditions and by the overfeed safety timer. All alarm settings shall be adjustable from the front panel.

6. All electronics shall be mounted on a single enclosed, plug-in PC board and shall be coated with a corrosion-proof coating. The pH sensor shall be potentiometric and shall be a sealed combination glass electrode.

7. The electronic module shall be covered by a standard manufacturer warranty of five (5) years. Special extensions of more limited manufacturer warranties shall not be considered acceptable. The mechanical parts and the sensors shall be covered by a standard one (1)-year manufacturer warranty. The manufacturer shall supply a complete instruction, operating and maintenance manual.

8. Exceptions to these specifications shall be described in detail together with a list of ten (10) similar operating systems of same model and manufacture with the name, address and telephone number of operating personnel.