Roof-mounted Air Conditioners, Heat Pumps, Heating Systems
What is a rooftop unit?
A rooftop unit is an appliance used to regulate and circulate air as part of heating, ventilating and air-conditioning (HVAC) system.
Commercial rooftop-mounted combined air conditioning or heat pump units
Rooftop mounted central air conditioning systems may include both the cooling unit (evaporator coil, blower fan, filters) and the compressor/condenser unit in one package.
Rooftop mounted central cooling systems may be smaller packaged systems which blow their cool air down directly into the cooled space through an opening in the roof, drawing return air from a nearby location, or the rooftop cooling system may be connected to duct work which blow down into multiple building areas to deliver cool air, drawing return air from one or more centralized returns.
In many commercial installations, the entire area over a suspended ceiling may serve as one giant return through which pass the supply ducts, delivering air to individual supply registers.
While the list above describes the common components of a typical residential air conditioning system, other configurations and packaged units are also used in both residential and commercial installations.
Alternative HVAC designs may combine all components except for the duct work in a rooftop mounted unit.
Split-System A/C Rooftop Mounted Air Conditioners & Heat Pumps
Installation requirements for rooftop-mounted split system compressors / condenser units include both a service disconnect and often additional measures to assure that the unit is properly padded to avoid damage to the roof membrane, and to assure that the unit is properly levelled.
Support Requirements for Rooftop-Mounted HVAC Equipment
Common inspection points & functional issues around rooftop-mounted HVAC equipment include:
-Adequacy of structural support – weight distribution
-Proper mounting and flashing at support base to avoid roof leaks
-Provision for working space for maintenance and repair
-Leaks into the HVAC equipment or duct system