An AUTOMATIC ORP CONTROL SYSTEM shall be supplied for continuous monitoring and control of the Oxidation-Reduction Potential (ORP or Redox) in water produced by an oxidizing sanitizer. The system shall be a CHEMTROL® 230 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 feature a digital readout of Oxidation-Reduction Potential (ORP or Redox) 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 the appropriate chemical feeder in order to maintain the Oxidation-Reduction Potential (ORP or Redox) of the Free Active Sanitizer level within 10 millivolts (mV) of the setpoint selected by the operator. Setpoint selection shall be by direct dialing on scales calibrated in mV of ORP.

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 a 3-digit LED digital readouts for mV of ORP or Redox.

5. Audible, visual and remote alarms shall be activated by high/ low sanitizer 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 sanitizer and pH sensors shall be potentiometric. The sensor shall be a sealed combination oxidation-reduction potential (ORP) electrode with a platinum ring having a minimum area of 0.5 cm2.

7. 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.


1. OPTION 4-20mA: The controller will include a 4-20 mA output with programmable control range.

2. OPTION High Pressure Probe: The controller will include a high pressure industrial ORP probe.


1. The controller electronics shall be covered by a standard manufacturer warranty of five (5) years. Special extensions of more limited warranties shall not be considered acceptable. All sensors will be covered by a standard one (1) year warranty. Other parts shall be covered by their own manufacturer's warranty. 2. The manufacturer shall supply a complete instruction, operating and maintenance manual.