The air handler cabinet is made of sheet metal and simply acts as a duct to guide the air through and to protect the air handler components and to protect people from the air handler components. Depending on the manufacturer will depend on the color of the unit. Trane air handlers are usually green,

Carrier air handlers are usually gray, Goodman, Janitrol, and York air handlers are usually brown (as many manufacturers use brown). Air handler components are the blower and can have air handler coils installed inside the air handler. Additionally, electrical controls for the air handler components along with dampers to control the airflow.

Air Handler Cabinet | HVAC Components

Commercial Air Handlers

Commercial air handlers are usually unpainted sheet metal especially McQuay but Carrier, York, and Trane will paint their commercial equipment before shipping. It simply depends on the manufacturer and what they decided to use to paint their equipment before shipping.

Hopefully, you can use this as a guide if there is no identifying information on the equipment. Sometimes the identifying information (nomenclature) for air handlers are hidden on the inside of the cabinet but it is not recommended to open the air handler cabinet unless you are a trained HVAC professional.

AHU Cabinet Construction

All manufacturers paint the air handler cabinets and depending on how they paint the cabinets will depend on the durability of the finish and in some cases the durability of the cabinet itself. Most air handler cabinets are constructed of steel and then a primer paint is applied followed by a final coat of the finished color.

The primer coat is the coat that will bond with the steel and prevent future rusting or corrosion of the cabinet as long as the cabinet is not scratched or the primer coat is not scratched off the cabinet and bare metal is visible.

A few manufacturers use a solid-state process of powder coating the primer coat and powder coating creates a near-permanent bond between the steel and the paint. The bond in powder coating can be down to the molecular level if the process is done correctly so the better cabinets will be ones that are powder coated.

AHU Maintenance | Air Handler Cabinet

In the way of maintenance for air handling units, there is little maintenance needed for AHU cabinets. If the air handler has been exposed to a rough environment and the paint is scratched or is fading as a result of direct sunlight it may be necessary to apply a coat of paint to the air handling unit to protect the metal from rust and corrosion. Some air handlers have doors that are accessed for maintenance purposes such as air filter maintenance or motor and belt maintenance.

Some older air handlers need to have screws removed to access essential parts of the air handler for maintenance and the screws and screw holes become stripped so they do not hold the doors on securely. It is necessary to repair these stripped-out holes and replace the screws so the access doors are held on securely.

This is especially true about rooftop units. These air handler access panels can come to lose either by the wind or by the unit’s vibrations when in operation and the wind can pick these panels up and throw them making them a hazard to people and property.

Air Handler Cabinet

The cabinet protects all the components. It is, therefore important, to ensure it is durable.

Air Handler Cabinet

Resource: The Home Comfort Book: The ultimate guide to creating a comfortable, healthy, long lasting, and efficient home