Fireye - United Technologies
Nexus NXEXP300 Water Level Control

Nexus NXEXP300 Water Level Control

The Fireye® Nexus® NXEXP300 is a microprocessor based, water level/draft control expansion module for use with the Nexus PPC6000 or integrated NX6100 series of parallel positioning controls.

The NXEXP300 expands the capability of the parallel positioning system by adding valuable safety rated digital inputs, sequence draft control, boiler water level control and total dissolved solids (TDS) surface and bottom blow down control. The small (5”L x 8.5”W x 3.75H) footprint, adjustable voltage (120/230, 50/60 hz.) and simplified wiring provide easy retrofit to existing Fireye systems.


  • Boiler Water Level
    • One, two or three element boiler water level control via 4-20mA inputs from field devices. Feed pump VFD and pump sequencing is also included.
  • Sequence Draft Control
    • Built in sequence draft control controls the boiler outlet damper through prepurge, light off and operation reducing standby and operating losses.
  • Total Dissolved Solid
    • Industry standard TDS probe provides the option to control surface blow down based on TDS levels set by operators.
  • Flexibility
    • Utilize proven Fireye CANbus servomotors or industrial 4-20mA current or I/P feed water valves.
  • Wiring
    • International voltage setting and simple four wire CANbus interconnections make wiring a snap. Safety relay contacts can be easily inserted into the existing control wiring.
  • Reliable Operation
    • Proven hardware with more than five years of in field service has been reconfigured to provide these additional features.

Documents & Resources