Fifteen years on a roof: when the package unit is ready to come down

The unit that’s done its time

A rooftop package unit over a St. Augustine storefront, installed when the plaza was built, has reached the age where the compressor amps climb every summer and the cabinet panels no longer seal. Fifteen years in Florida sun is a full career for equipment that lives entirely outdoors. The owner’s question is what goes back up on the curb.

The problem a package unit solves

A split system needs two places: an indoor spot for the air handler or furnace and an outdoor spot for the condenser, plus refrigerant lines between them. Plenty of buildings don’t have the indoor spot. Single-story commercial buildings with no mechanical room. Manufactured homes with no closet to spare. Houses on tight lots or with no attic access. For all of them a package unit puts the coil, blower, compressor and heat source in one weatherproof cabinet outside, connected to the building only by two duct openings and a power feed.

That also makes it the easiest equipment to service: everything is in one place, at grade or on a roof, with no attic crawl.

The configurations

Package units come in the same functional types as split systems, and Cook’s installs Lennox versions of each:

• Package air conditioner with electric heat, the simplest, for buildings with little heating need.
• Package heat pump, the common choice in this territory for the same reasons heat pumps dominate in homes.
• Package gas/electric, cooling with a gas furnace section, for gas-served commercial buildings.
• Dual-fuel package units, a heat pump with gas backup, where both economy and gas are wanted.

Efficiency tiers and capacities span small residential units to large commercial rooftops; the model that fits goes on the quote. Ask about the upper tonnage Cook’s installs if your roof carries large units. [[CONFIRM WITH JERRY]]

Installation notes

Rooftop work is a crane job: the old unit is disconnected and lifted off, the curb adapted if the new unit’s footprint differs, the new unit set, and the duct, electrical and gas connections remade. Cook’s schedules the lift for a morning the business is closed or slow, and most changeouts are done before lunch. Pad-mounted residential units are set by hand or small equipment on a new pad, with the duct connections under the home sealed properly, which is where most manufactured-home systems were losing air to begin with.

Care

A package unit’s whole life is outdoors, so maintenance is about the cabinet as much as the refrigeration: panels and gaskets, the condensate drain, the coil rinsed of salt or pollen, belts and bearings on larger units, the economizer and filters on commercial models. A commercial agreement should log each unit by number, so ask how yours will be documented; residential package units join the regular maintenance schedule. Manufacturer warranties are registered by Cook’s; ask for the labor warranty term in writing. [[CONFIRM WITH JERRY]]