Finishing Systems for HVAC Equipment Makers

Where Powder Lines Fit Cabinets and Panels

Sheet metal panels and cabinet parts are well suited to a conveyorized powder coating line: parts hang on an overhead conveyor, pass through pretreatment, dry off, enter a powder booth, then travel through a conveyor cure oven before unloading. The line runs continuously, color changes can be planned around production schedules, and overspray can be reclaimed in many booth designs. The main design questions are part size, hanging method, line speed relative to fabrication output, and how many colors the plant runs. Plants with many colors or frequent changes often choose booths built for quick color change, while plants running mostly one color can favor high reclaim efficiency.

• Define the largest panel or cabinet part the conveyor must carry.
• Decide how parts hang and how hooks and racks are stripped and maintained.
• Plan load and unload stations near fabrication and assembly.

Pretreatment Ahead of the Powder Booth

Coating performance on HVAC equipment, which often sits outdoors on rooftops or beside buildings, depends heavily on pretreatment. Washer stages clean oils and shop soil from the metal and apply a conversion coating before the part dries and enters the booth. The washer needs water supply, drains, heat for the stages, exhaust for vapor and a plan for chemical handling. A dry-off oven follows the washer to remove moisture before powder. These pieces add utilities and floor space but are what make powder coating durable on outdoor equipment. If a full washer does not fit, some plants use a manual wash booth for lower volumes, which still needs drainage, ventilation and water.

Liquid Booths for Housings, Large Assemblies and Touch-Up

Not every HVAC part fits a powder line. Large fan housings, assembled units, heavy bases and parts with heat-sensitive components are often painted in a liquid booth instead. Crossdraft booths work for most of these parts and fit on a flat floor. Larger assembled units may need a drive-in booth with a cart or overhead crane. A touch-up booth near final assembly lets the plant repair handling damage without sending units back to the main line. Liquid booths need their own exhaust, make-up air, filtration, lighting and fire protection, and those connections should be planned alongside the powder line so the building stays balanced.

• Use a separate booth for touch-up so it does not interrupt line coating.
• Plan cart or crane access for assembled units.
• Consider a paint mixing room for storing and mixing liquid coatings safely.

Cure Ovens, Heat and Building Balance

Powder lines rely on cure ovens, and HVAC plants usually use conveyor ovens matched to line speed. Oven sizing depends on part mass and how long parts must stay at cure conditions, which is driven by the powder manufacturer's data sheet. The oven's burners or electric heat, exhaust and controls all connect to building utilities. Powder booths, washers and liquid booths each exhaust air, and the plant needs make-up air units to replace it. When those units are planned together, the building stays near neutral pressure, doors open normally and dust from fabrication is not drawn into the coating area. Exhaust stacks, oven flues and rooftop make-up air units need roof structure, curbs and coordinated placement so exhaust does not re-enter through intakes.

Maintenance and Pre-Install Checklist

A powder line that runs every shift needs easy access to booth filters, cartridge collectors, oven burners, conveyor drives and washer pumps. Leave aisles around each piece of equipment and plan how filters and chemicals are delivered. Before a site visit, gather the following so the system can be scoped accurately.

• Part drawings or samples for the largest and most common parts.
• Target output per shift and the number of colors run.
• Building drawings with columns, roof structure and floor drains.
• Location and capacity of gas, electrical, water and compressed air.
• Any existing booths or ovens being reused, moved or removed.