Trane A951X040BD3SA Gas Furnace 40000 Btu/h 95% Afue Single Stage Dedicated Downflow

Product Description

The Trane A951X040BD3SA is a single-stage, dedicated downflow condensing gas furnace rated at 40,000 BTU/h input capacity and 95% AFUE (Annual Fuel Utilization Efficiency). It operates on a 24-volt control circuit and delivers up to 1,200 nominal CFM through a multi-speed blower. The unit is designed for direct-vent, sealed-combustion installations and is compatible with both natural gas and LP gas configurations. Licensed HVAC technicians install this furnace in residential forced-air heating systems where a downflow configuration is required by the application layout.

The A951X040BD3SA is configured exclusively for downflow orientation, making it well suited for installations where supply air must be directed downward into a subfloor duct system or beneath a raised structure. The 9-tap control transformer module (CTM) provides flexibility during commissioning. The cabinet measures 17.5 inches wide, 28.75 inches deep, and 34 inches tall, fitting standard residential utility closets and furnace alcoves designed for downflow equipment.

Key Features

• 40,000 BTU/h input capacity with 95% AFUE for high-efficiency condensing operation
• Dedicated downflow configuration only — not field-convertible to upflow or horizontal
• Multi-speed blower with 1,200 nominal CFM airflow
• 24-volt control circuit with 9-tap CTM for field adjustment
• Direct-vent, sealed-combustion design supports natural gas and LP gas
• Compact cabinet at 17.5 inches wide fits standard residential furnace openings

Compatibility

Designed as an OEM downflow condensing gas furnace for residential forced-air heating systems. Compatible system pairings documented in web evidence include the A4AC3036D1 outdoor condensing unit with a 4MXCB006AC6HCB coil for a complete downflow split system. Consult Trane submittal document A951X040BD-SUB-1C-EN for full system compatibility guidance.

Installation Notes

Installation must be performed by a licensed HVAC technician in accordance with local mechanical codes, the IFGC, and the manufacturer's installation instructions. Shut off the gas supply and disconnect electrical power at the breaker before any service or installation work. This unit requires a dedicated direct-vent flue system — do not connect to a conventional B-vent or masonry chimney without verifying compatibility per the venting tables in the installer guide. Condensate drain lines must be properly trapped and routed per local plumbing codes.

Technical Specifications

• Input Capacity: 40,000 BTU/h
• AFUE: 95%
• Stages: Single stage
• Airflow (Nominal): 1,200 CFM
• Control Voltage: 24 volts
• CTM Taps: 9
• Configuration: Dedicated downflow only
• Cabinet Width: 17.5 inches
• Cabinet Depth: 28.75 inches
• Cabinet Height: 34 inches
• Fuel Type: Natural gas or LP gas
• Venting Type: Direct vent, sealed combustion

Standard Information

• Brand: Trane
• Manufacturer Part Number: A951X040BD3SA