Product Description

The LT-420 is a unique device used for water level indication on Section I boilers and other boiler feedwater applications. The unit combines several standard features in order to satisfy modern boiler code requirements, and at same time address challenging aspects of water/steam level applications. ASME BPVC.I-2019 PG-60.1.1 requires a Remote Level Indicator (RLI), to continuously measure, transmit and display the water level in the control room. The RLI is a discrete system that monitors the water level, independent of the DCS. Paired with a GWR transmitter, the LT-420 provides a reliable solution for water level indication.

Product Features

  • 4-20mA Output Signal
  • Programmable Alarm & Trip Points from Guided Wave Radar
  • Serial Remote Display Signal – Optional Fiber Optic
  • Ability to power three remote indicators
  • 4 – Relays, 8 AMP per relay
  • ASME PG60.1.1.2 Code Compliant

Product Specifications


Relay Contact Rating: (4) Relays, 8 Amp (per relay)
Operating Temperature: Electronics: 32 ̊F-140 ̊F (0 ̊C – 60 ̊C) Column: 750 ̊F (400 ̊C)


NEMA4X/IP65 Wall mounted glass-fiber reinforced polyester (stainless steel is available as an option) Dimensions: 11.42” H X 9.79” W X 6.56” D (290 mm H X 249 mm W X 167 mm D)
Ambient Operating Temperature Rating: -13o F (-25o C) to 158o F (70o C)

Power Supply

Single 100-240 VAC ± 10%, 48 – 63 Hz Optional 24 or 48 VDC


Additional options can be purchased to customize the LT-420 System to individual applications.

  • Additional remote displays
  • Column ratings: Up to 3000psi maximum and 1200 ̊F maximum Column materials: Carbon Steel, Stainless Steel and Chrome Moly
  • Auxiliary relay module

Compatible Products


Document Title Category
LT-420 Control Unit for GWR
Level-Trac, Product Literature
Level-Trac paired with GWR Fact Sheet