The M720 pH/ORP Controller is a device designed for automatic monitoring and management of pH and ORP (Oxidation Reduction Potential) levels in swimming pools, spas, or other circulating water environments. It provides a user-friendly interface for controlling water balance and chemical dosing.
Function Description:
The M720 pH/ORP Controller allows for automatic monitoring of pH and ORP levels. It features LED indicators and digital readouts on the front panel to display current pH and ORP levels. The controller is equipped with five function buttons for individual parameter control:
- Mode: Switches between Auto and pH Standby (programming) modes.
- Set Level: Used to define the desired pH level to be maintained.
- Dose Timer: Configures timed or continuous chemical feed modes.
- Delay Time: Sets a delay period after each dose time.
- pH Cal: Used for pH calibration.
When the pH level deviates from the set level (rises for acid feed or falls for base feed), the controller activates the chemical feeder for a set dose time, followed by a set delay time. This cycle continues until the desired pH level is reached. Similarly, when the ORP (sanitizer) level deviates from its set level, the controller activates the chemical feeder for a set dose time, followed by a set delay time, until the set level is reached.
The system includes an injection-molded flow cell with an integrated flow switch, which houses the pH and ORP sensors. This flow cell works in conjunction with the M720 controller to monitor water levels. The flow switch verifies that water is flowing during a feed cycle and deactivates the controller if water is not flowing. Operation without a functioning flow switch will void the NSF Certification.
Important Technical Specifications:
- Enclosure Dimensions: 6.375"L x 4.75"W x 3.5"D (Mounting board dimensions are 16"L x 12"W x 0.25"D).
- Electrical Input/Output: 110/230 VAC, 50 - 60 Hz.
- pH Set Level: 7.0 to 8.0.
- ORP Set Level: 400 mV to 900 mV.
- Dose Time: Off, Continuous, or Timed cycle.
- High Alert (Default): pH 8.0, ORP 900 mV.
- Low Alert (Default): pH 7.0, ORP 100 mV.
- Readout: Function LED and numerical digital displays.
- Alarm: Red alert LEDs.
- pH Output (left receptacle): Max. 5 amps @ 110/230 VAC.
- ORP Output (right receptacle): Max. 5 amps @ 110/230 VAC.
- AC Power: 110/230 VAC, 50-60 Hz.
- pH Sensor Connection: BNC connection.
- ORP Sensor Connection: BNC connection.
Dip Switches (1-4):
- 1: pH/ORP interlock (default: OFF): No ORP feed if pH is feeding (ON).
- 2: pH/ORP alert interlock (default: ON): No ORP if pH is in alert mode (ON).
- 3: Acid/Base default acid (default: OFF): Feeds base chemical when pH level falls below set point (ON); feeds acid chemical when pH is above set point (OFF).
- 4: Over Timer ON/OFF (default: ON): Turning off the Over Timer will void any NSF Certification.
Usage Features:
- Digital Displays and Function LEDs:
- pH: Red LED for Alert, Green LED for Dose.
- ORP: Red LED for Alert, Yellow LED for Dose.
- Mode - pushbutton adjustments:
- Auto - red LED.
- pH standby - green LED.
- ORP standby - yellow LED.
- OFF mode - In standby, press and hold Mode button for 3 seconds to turn controller off.
- Flow - green LED.
- Up/Down button: Adjusts Set Level, Dose Time, Delay Time, and pH Cal.
- pH Standby Mode:
- Green pH standby LED illuminates, pH and ORP digital displays show dashes, and all Auto functions are disabled.
- Set Level: Default 7.4 pH, selectable range 7.0 – 8.0 pH (in 0.1 increments).
- Dose Time: Default 10 seconds ON, 5 minutes OFF. Selectable range OFF, CON (continuous), and Timed (0.6 - 900 seconds ON and 5 minutes OFF). Dose LED flashes while dosing, illuminates steadily during delay.
- Delay Time: Default 5 minutes after dosing. Selectable range 1 – 99 minutes.
- Over Timer: Preset 60 timed cycles or 60 minutes in continuous feed. Selectable range in timed feed: OFF, 20 – 100 feed cycles. Selectable range in continuous feed: OFF, 20 – 180 minutes. The Over Timer is interlocked with the Dose Time selection. If the Dose Time is set to a timed cycle, the Over Timer counts timed feed cycles and resets when the set level is reached. If the preset cycle count is reached, the pH digital display flashes, and the pH output relay de-energizes, requiring manual reset. If Dose Time is continuous, the Over Timer counts in minutes.
- High Alert (pH): Default 8.0 pH. Selectable range OFF, 7.5 pH to 8.4 pH (acid feed). Triggers if pH remains above the High Alert level for 10 continuous minutes, disables pH dose output. Automatically turns off when pH falls below the alert level for 1 continuous minute.
- Low Alert (pH): Default 7.0 pH. Selectable range OFF, 6.8 pH to 7.4 pH (acid feed). Triggers if pH remains below the Low Alert level for 10 continuous minutes, disables pH dose output. Automatically turns off when pH rises above the alert level for 1 continuous minute.
- pH Cal: Allows pH reading adjustment of ±0.9 pH from actual sensor reading. Default 0 pH adjustment.
- ORP Standby Mode:
- Yellow ORP standby LED illuminates, pH and ORP digital displays show dashes, and all Auto functions are disabled.
- Set Level: Default 650 mV. Selectable range 400 mV to 900 mV (in 5 mV increments).
- Dose Time: Default 10 seconds ON, 5 minutes OFF. Selectable range OFF, CON (continuous), and Timed (0.6 to 900 seconds ON and 5 minutes OFF). Dose LED flashes while dosing, illuminates steadily during delay.
- Delay Time: Default 5 minutes after dosing. Selectable range 1 – 99 minutes.
- Over Timer: Preset 60 timed cycles or 60 minutes in continuous feed. Selectable range in timed feed: OFF, 20 – 100 feed cycles. Selectable range in continuous feed: OFF, 20 – 180 minutes.
- High Alert (ORP): Default 900 mV. Selectable range 650 mV to 900 mV, no OFF. Triggers if ORP level remains above the High Alert level for 10 continuous minutes, disables ORP1 dose output. Automatically turns off when ORP falls below the alert level for 1 continuous minute.
- Low Alert (ORP): Default 100 mV. Selectable range OFF, 100 mV to 640 mV. Triggers if ORP level remains below the Low Alert level for 10 continuous minutes, disables ORP1 dose output. Automatically turns off when ORP rises above the alert level for 1 continuous minute.
- pH Cal disabled in ORP standby mode.
Maintenance Features:
- Winterizing: Turn off the controller and main power. Remove pH and ORP sensors, fill protective caps with water, and store in a warm, secure location. Drain water from the flow cell.
- Cleaning Sensor Tips:
- Sensor tips should be cleaned every 1-3 months for commercial pools/spas, and every 3-6 months for residential pools/spas.
- Turn off the M720 controller.
- Close the right and left valves at the bottom of the flow cell.
- Loosen the nut fitting and gently remove the sensor from the flow cell.
- Swirl the sensor tip for 5 seconds in Muriatic acid or white vinegar, then rinse with water. Do not touch or brush the sensor tip.
- For commercial pools/spas, every 3rd cleaning, swirl the sensor tip in a liquid soap and water solution, then rinse.
- Gently re-insert the sensor into the flow cell and hand tighten the nut fitting.
- Turn on the M720 controller, open flow cell valves, and allow the system to stabilize for accurate readings. Adjust Set Level if necessary.
- If the sensor does not show indicated readings, it must be replaced.
- Factory Defaults: To return the controller to factory defaults, place the controller in pH Standby Mode, turn off the controller by holding down the Mode pushbutton. Then, press and hold both the Set Level and pH Cal pushbuttons, and then press the Mode pushbutton. The pH display will show "Ld" and the software version number will display in the ORP window. The controller will be returned to the factory default functions and placed in the test mode. To exit test mode, turn off the controller with the Mode pushbutton. Failure to complete this action will leave the controller in the test mode.
Need help?
General
To Next Page
