Marley® AIO (All-in-One) Control Panel
OVERVIEW The Marley® AIO Control Panel integrates multiple cooling tower control functions into one convenient and cost-saving panel – reducing field installation and startup time – benefitting the installing contractor and end user. Typically, each cooling tower cell uses one AIO control panel. Only a single-point incoming power connection is required to power the several integrated electrical control circuits included; all circuits are factory tested with associated sensors, and VFD is preprogrammed to jobsite motor and speed control signal.


Control options built into the AIO Control Panel are customer-configurable based on bid specification and job site requirements. A typical combination is the Variable Frequency Drive (VFD) for the fan motor, Basin Heater control, Water Level control, and Vibration Switch interface. The AIO Control Panel is operator-friendly with easy-to-understand visual displays and built to UL508A Industrial control panel standards.


  • NEMA 3R outdoor painted steel enclosure with cooling vents.
  • Main circuit breaker provides thermal and short circuit overload protection for the control panel. A single-point incoming power connection then distributes and reduces voltage to power various integrated control features. No upstream MOCP-rated device is required to protect the AIO control panel.
  • Local lockout/tagout padlock provisions provided at the panel’s main disconnect.
  • Integrated VFD is factory programmed with Marley cooling tower parameters and motor data.
  • Vibration switch interface for power and control.
  • Oil level switch interface circuit for power and control.
  • 120 VAC power for heat trace circuit when required for external water level stilling chamber.


  • By-pass motor starter.
  • Stainless steel NEMA 3R outdoor enclosure.
  • 65,000 SCCR (short circuit current rating).
  • Marley ABH (Advanced Basin Heater) cold-water basin heater controller.
  • 4-20mA transmitter card for remote monitoring of cold-water basin temperature.
  • LLC conductivity water level controller with makeup, alarms and cutout circuits.
  • LLC+u ultrasonic water level controller with makeup, alarms and cutout circuits.
  • VFD startup service, if required.

  • Integrated, single-point power connection

  • Fewer power feeds

  • Pre-programmed and functionally tested

  • Water level controls optional

  • Basin heater circuit optional

  • Vibration and oil level switch interface circuits

  • Lockout/Tagout provisions provided


Marley Cooling Tower Parts