Product Description

The Level-Trac Model LT-220 Electronic Control Unit is a component of a remote level indication system, as described in ASME Section I, PG-60. The control unit may also be used as an alarm or trip device. Discrimination between water and steam is based on the significant difference in resistivity between the two states over the saturation range. The control unit interprets and displays the signal from up to 14 probes mounted in a probe manifold. Via voltage applied to the probe tip, conduction in the presence of water will occur between the tip and the inside wall of the column.

Typically, probes are spaced horizontally in a manifold attached to the steam drum, with each probe connected to its own sensing and water/steam indication circuit. A vertical display of Green/Red indicators provides a simulation of water level in the steam drum. Spacing between probes is per customer requirements to cover the visible range and alarm or trip points.

Product Features

  • One to Fourteen Probe Channels
  • 4-20mA Output Signal
  • Field Programmable Alarm and Trip Points
  • Voting Logic for Trips
  • Serial Remote Display Signal
  • Sequence Fault Detection
  • Dual Power Supply

Product Specifications


  • 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)


  • Up to 14 independent channels numbered in ascending order
  • Sensitivity may be selected between three conductivity ranges
  • One or two wire connection to the Probe depending on whether the probe is normally immersed in water or steam.
  • Probe wire discontinuity will resulting an indication of the channel to the opposite state to initiate sequence fault

Power Supply

  • Two Discrete 100-240 VAC ± 10%, 48 – 63 Hz
  • Failure of one Power Supply or Source will not affect performance of the Control Unit (Fault will be indicated.)

Relay Outputs

  • Two Alarms
  • Two Validated Trips
  • One Fault
  • 2 out of 3 Probe channel voting circuit
  • Relay Rating: DPDT, Max. Current: 8 Amps @ 250VAC


Compatible Products


Document Title Category
300-04 Level-Trac LT 220, Electronic Control Unit
Product Literature
200-00 Level-Trac & Steam-Trac Brochure
Brochures, Product Line Brochure
330-32 LT-220 IOM
Combo Unit:  Guided Wave Radar & Level-Trac Control Unit Display
Product Literature
Steam-Trac and Level-Trac RFQ Form