LS25-200S-1​ Separated Combustion Unit Heater, 200,000 Btuh, Stainless Steel

Cat # : 20U17  |  Model/Part # : LS25-200S-1​

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Product Overview

LS25-200S-1​ Separated Combustion Unit Heater

Increased Application Flexibility

The LS25 Separated Combustion Unit Heaters utilize high-temperature silicone gaskets to provide a superior seal and leakage rates that are up to 57% lower than those allowed under ANSI Z83.8. Lennox goes above and beyond to deliver a tight, durable seal because that is the key to unmatched durability and efficiency over the life of a separated combustion product in harsh environments.

  • Designed for use in applications where the indoor environment may contain airborne contaminants, VOC’s or dust
  • Ideal for hard-to-heat applications where excessive humidity or negative pressure is a concern
  • Dimpled Tubular Heat Exchanger improves efficiency (82%) and increases durability
  • The hinged door allows easy access to components
  • Optional stainless steel heat exchangers provide superior resistance to corrosion and oxidation
  • Sidewall venting eliminates roof penetrations
  • Self-diagnostic board with LED display improves troubleshooting efficiency and accuracy


  • Separated combustion units offer a robust heating solution for buildings with harsh indoor environments.
  • Fresh-air intake box can be rotated 180˚ degrees for increased installation flexibility in retrofit applications


  • Cage-nuts for all-thread installation on vertical units
  • Conveniently located gas connections
  • Removable terminal block for line voltage and thermostats
  • The hinged door allows easy access to all components
  • DSI control board has 11 diagnostic codes and remote LED fault detection diagnostics enabled

Brand Lennox
Catalog Number 20U17
Model/Part Number LS25-200S-1​
Minimum Order Quantity 0.0
Base Unit of Measure Unit(S)
Product Depth 46 Inches
Product Height 35.25 Inches
Product Width 33 Inches
Product Voltage 115v 1ph 60 hz
Gross Weight 192 LB
Family LS25
Heating Capacity 200, 000 Btuh
Efficiency 83.0 AFUE
New Catalog #'s
New Catalog #'s
20U17 was replaced by

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