Lennox CBX27UH - User Manual

The Lennox Elite® Series CBX27UH is a multi-position air handler designed for indoor use, capable of operating in up-flow, down-flow, and horizontal (left-hand or right-hand discharge) configurations. It is intended for installation with an optional field-installed electric heat section and a matching HFC-410A outdoor unit.

Function Description

The CBX27UH air handler is a key component of a complete heating and air conditioning system. Its primary function is to circulate conditioned air throughout a building, working in conjunction with an outdoor unit (condensing unit or heat pump) and an optional electric heat section. The unit draws return air from the conditioned space, passes it over an evaporator coil (for cooling) or an electric heat element (for heating), and then delivers the conditioned air back into the supply ductwork.

The unit's multi-position design allows for flexible installation in various residential or commercial settings. It is factory-configured for up-flow and horizontal right-hand discharge, with field modifications required for down-flow or horizontal left-hand discharge applications.

Usage Features

Multi-Position Installation: The CBX27UH can be installed in up-flow, down-flow, horizontal right-hand, or horizontal left-hand configurations, offering versatility to suit different building layouts and space constraints.
Optional Electric Heat: The unit is designed to integrate with an optional field-installed electric heat section, providing supplementary or primary heating capabilities.
Blower Speed Adjustment: The blower motor speed can be adjusted via speed taps on the low voltage terminal strip in the control section. This allows for optimization of airflow (CFM) based on the specific system requirements, such as matching nominal tonnage or adjusting for high static applications. The motor is programmed with a 45-second delay-off on most speed taps, ensuring controlled shutdown.
Condensate Management: The unit includes a main drain and an overflow drain to manage condensate produced during cooling operations. Proper installation of a drain trap and routing of the drain lines are crucial to prevent water blow-off problems and ensure efficient condensate removal. For horizontal applications, a secondary drain pan is recommended, and for down-flow orientations, the overflow drain must be connected to an overflow drain line.
Refrigerant Line Connections: The unit is equipped with factory-installed, internally mounted check/expansion valves and is designed for brazing connections to refrigerant lines. Nitrogen purging during brazing is essential to prevent oxidation and moisture introduction into the system.
Electrical Connections: The unit requires line voltage power supply from a circuit breaker and low voltage wiring from an outdoor unit and thermostat. Separate knock-outs are provided for 24V low voltage and line voltage wiring to prevent interference. Wiring must conform to national and local electrical codes.
Air Filtration: The unit includes a filter for air purification. Filters should be inspected regularly and cleaned or replaced as needed to maintain proper air handler operation.

Maintenance Features

Easy Access for Service: Access panels are designed for easy removal, facilitating maintenance and service of internal components such as the blower and coil assemblies.
Filter Maintenance: Filters are accessible and can be removed for cleaning or replacement. Reusable filters can be washed with water and mild detergent, while throw-away filters should be replaced when dirty. Regular filter inspection (monthly) is recommended to ensure proper airflow and unit efficiency.
Condensate Drain Inspection: It is important to periodically check the drain pan plugs and drain holes to ensure they are fully open and free of debris. This prevents blockages that could lead to water blow-off issues.
Cabinet Insulation Repair: The unit's cabinet contains insulation to maintain thermal integrity. If the insulation becomes wet, damaged, separated, or torn, it must be repaired or replaced. Areas of condensation on the cabinet surface indicate a need for insulation repair. Repair involves cutting an X pattern, peeling open, applying all-purpose glue, and pressing the tabs back, ensuring full coverage to prevent air pockets and sweating. For foil-faced insulation, any cuts or tears should be taped with a similar foil-faced tape.
Static Pressure Measurement: The unit allows for static pressure measurement using a manometer, which helps in diagnosing airflow issues and ensuring optimal performance. Tap locations are provided for this purpose.

Lennox CBX27UH Specifications

General

Type	Air Handler
Brand	Lennox
Model	CBX27UH
Efficiency	Up to 16 SEER
Refrigerant	R-410A
Heating Capacity	Varies by model
Nominal Heating Capacity	Varies by model
Airflow	Up to 2000 CFM
Coil Type	Aluminum
Voltage	208/230V
Sound Level	Quiet operation
Height	Varies by model
Width	Varies by model
Length	Varies by model
Weight	Varies by model
Nominal Cooling Capacity	1.5 to 5 tons
Motor Type	ECM
Cabinet Construction	Heavy-gauge, painted steel
Insulation	Fully insulated