Thermo King RLF Series

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Thermo King
RLF Series



Integrated rooftop bus HVAC system for coach and transit applications. Replaces existing roof-mount units with a unit that weighs 42% less and replaces rear-mount units without sacrificing reliability, performance, weight or cost!

  • Unique 1-piece design
  • Single roof cutout to prevent leaks
  • Single evap heater assembly (reduced plumbing)
  • Next generation IntelligAIRE® III control system
  • Next generation brushless motors
  • Lowest weight of any rooftop unit
  • Fits CNG, hybrid and diesel buses
Standard Features
  • IntelligAIRE® III Control System: Expanded CAN communications capability; Plugs directly into J1939 network to make more info available; Eliminates the gateway module required between bus & unit controllers; Less weight due to elimination of harnesses; Increased number of I/O for system & component monitoring; Eliminates need for expansion modules external to controller where multiple zones must be controlled independently; Programmable pre-heater function with real time clock activation to start pre-heat when system is off
  • HFC Refrigerant R-134a or R-407C: Environmentally safe alternative providing protection for the earth’s ozone layer
  • The Thermo King X430 Compressor: Engineered exclusively for transport applications; Built for extended service life; Field repairable
  • Next Generation Brushless Motors: Integral electronics; No external controllers; Maintenance free; Advanced diagnostics; Programmable variable speed; Eliminates wiring harnesses, terminals and studs; Failure mode indication
Optional Features
  • S391/S616 Screw Compressors: Exclusive oil management system for increased reliability; Fewer moving parts than reciprocating compressors; Lower noise levels and vibration than reciprocating compressors; Programmable capacity control for fuel savings
  • Electronic Energy Management System: Provides fuel savings with X426, X430 and X640 reciprocating compressors; Programmable electronic capacity control reduces the parasitic load on the engine
System Cooling Capacity
  • R-134a: 88,500 BTU/hr; 26 kW; 22,292 Kcal/hr
  • R-407C: 105,000 BTU/hr; 30.8 kW; 26,448 Kcal/hr
  • Rated Capacities are at the following conditions: Outside: 35°C/95°F; Inside: 27°C/80°F DB, 19°C/67°F WB
System Heating Capacity
  • At 30 Lt./Min.(8 GPM) coolant flow rate and 55K (100°F) temperature differential between return air and coolant.
  • BTU/hr: 105,000
  • kW: 30.8
  • Kcal/hr: 26,448
Evaporator Airflow
  • (0 in. water column external static pressure)
  • High Speed: 2400 ft3/min
  • Medium Speed: 1370 ft3/min
  • Low Speed: 1000 ft3/min
  • HFC R-134a or HFC R-407C
Power Consumption @ 24 VDC
  • 102 Amps
  • 500 lbs (227 kg)
Compressor Weight with Clutch (approximate)
  • S391: 147 lbs (67 kg)
  • S616: 171 lbs (77 kg)
  • X426/X430: 115 lbs (52.2 kg)



Cooling Capacity
88,500 BTU/hr (26 kW)
Heating Capacity
105,000 BTU/hr (30.8 kW)


Airflow Volume
High Speed: 2400 ft3/min


500 lb. (227 kg)
102.55 x 52 x 26.09 in.