Trane A951X040BU3SA Gas Furnace 40000 Btu 96% Afue Upflow Horizontal Single Stage

Product Description

The Trane A951X040BU3SA is a single-stage, condensing natural gas furnace rated at 40,000 BTUH input with a 96% AFUE efficiency rating. Part of the RunTru by Trane A951X series, this unit is engineered for upflow installations with field-convertible horizontal right or horizontal left configurations. It uses a CTM multi-speed motor with nine available speed taps and an integrated furnace control board with a seven-segment LED display for diagnostics. Licensed HVAC technicians install this unit in residential forced-air heating systems where high efficiency and compact cabinet sizing are required.

The A951X040BU3SA is designed for residential upflow and horizontal applications. The 17.5-inch cabinet width makes it suitable for installation in closets, utility rooms, alcoves, and attic spaces where a convertible configuration is needed. It functions as a single-stage heating system and is commonly paired with a central air conditioner or heat pump in split-system configurations. Compatible system examples documented by the manufacturer include the A4AC4024D1 air conditioner and 4MXCB006AC6HCB coil as part of a complete heating and cooling system.

Key Features

• 40,000 BTUH input heating capacity with approximately 38,800 BTUH first-stage output
• 96% AFUE single-stage condensing operation for high-efficiency natural gas heating
• CTM multi-speed motor with nine speed taps for airflow flexibility
• Upflow configuration with field-convertible horizontal left or horizontal right orientation
• 17.5-inch cabinet width fits standard residential closet and utility room openings
• Integrated furnace control with seven-segment LED display for fault code diagnostics

Compatibility

Documented in system configurations with the A4AC4024D1 air conditioner and 4MXCB006AC6HCB coil for a 2-ton, 14.3 SEER2 upflow heating and cooling system. Designed as an OEM-style replacement or new-installation unit within the RunTru by Trane A951X series of residential gas furnaces.

Installation Notes

Installation must be performed by a licensed HVAC technician in accordance with local mechanical codes, the IFGC, and NFPA 54. Shut off gas supply and disconnect electrical power before beginning any service or installation work. The unit requires a direct-vent condensing flue system with PVC or CPVC vent pipe sized per the manufacturer installation guide. Condensate drainage must be properly routed and trapped to prevent blockage of the heat exchanger drain.

Technical Specifications

• Heating Capacity (Input): 40,000 BTUH
• Heating Capacity (Output, 1st Stage): 38,800 BTUH
• AFUE: 96%
• Fuel Type: Natural Gas
• Staging: Single Stage
• Motor Type: CTM Multi-Speed
• Number of Motor Speeds: 9
• Configuration: Upflow, Convertible to Horizontal Left or Horizontal Right
• Cabinet Width: 17.5 inches
• Efficiency Tier: High Efficiency
• Series: RunTru by Trane A951X

Standard Information

• Brand: Trane
• Manufacturer Part Number: A951X040BU3SA