ESDI Model 503 – Reverse Osmosis System Controller

with “Run Time” Hour Meter & Delivery Pump Control

click to enlarge image

The ESDI Model 503 Reverse Osmosis System Controller is an electronic circuit board assembly that performs all of the functions necessary to operate an industrial/commercial reverse osmosis water purification system. This dedicated control board incorporates flush cycles, an auxiliary pump control and features that make it cost effective and easy to use.  

  • Maintains water storage tank level, with a Hi level tank sensors.
  • Automatic membrane flush cycles with selectable times and frequencies. 
  • Auxiliary relay & tank Lo level sensor, for delivery system. (120VAC/240VAC, 3A Rated)
  • Lockout inputs for feed water pressure TDS monitor, & eater softener pre-processor.
  • Hour meter output connects to counter to display run time.
  • Controls membrane Flush Valve & Water Feed Valve (120VAC/240VAC, 3A Rated).
  • Pump control relay rated for 3/4HP/120VAC and 1HP/240VAC (12 Amp Max).
  • Optional RS232 serial communications port for SCADA monitoring.
  • Power Requirement: 120VAC or 230VAC, 50/60 Hz.
  • Board Size: 6” X 6.75”.                                           Enclosure Size: 11.5” X 7.75” X 6”


Model 503 Data Sheet
Model 503 Manual & Specifications

All of our products come with a Two-year Warranty. Your satisfaction is guaranteed.