Maintaining Packaged Rooftop Units

Packaged air-conditioner and heat-pump systems, also called rooftop units (RTUs), fall into disrepair over time, leading to energy waste and compromised comfort for a building’s occupants. It’s crucial to maintain these RTUs on a regular basis to ensure that they cool buildings and occupants as intended without wasting energy. Regular maintenance will also help to prevent or quickly catch malfunctions before they have a chance to further degrade the equipment or waste prodigious amounts of energy. An economizer stuck in the open position in a climate such as that of Tampa, Florida, for example, can cause the HVAC system to use 50 percent more energy than a system without an economizer.

Because a large part of the cost of servicing an RTU is incurred just getting service personnel and equipment on site, it doesn’t make sense to use a piecemeal approach that only addresses one or two maintenance measures at a time. Rather, use an annual service or maintenance program or contract to maintain the entire unit.

These contracts typically include a host of measures. Several of these, including cleaning both the condenser and evaporator coils, verifying refrigerant charge levels, and maintaining the RTU cabinet integrity are covered here. Other measures, such as changing filters and maintaining fans and outside air dampers, are covered in our Maintaining Air-Handling Equipment topic, because they also apply to equipment other than RTUs. Based on a short survey of service providers, the cost for an annual maintenance contract that includes all of these tasks is between approximately US$1,000 and $1,200 for a 10-ton unit. Filter changes and inspections are frequently performed quarterly, with the remaining tasks performed annually.

Cleaning Condenser Coils
Cleaning Evaporator Coils
Fixing Refrigerant Leaks
Maintaining Cabinet Integrity