Rooftop Unit Maintenance: Checks For Success

Before we dive into the rooftop unit maintenance checks, you should be performing on your units, lets cover the basics. We will talk through how a rooftop unit works, and its main components. Then we will discuss the maintenance that needs to be performed on each unit.

Two installed Roof Top Units

What Is A Rooftop Unit?

A rooftop unit is a package unit that is located on the rooftop (go figure). They provide conditioned air for a facility and push it through the facility using ductwork. These units are self-contained, meaning they have everything they need to condition air located inside of them.

What Are The Main Components Of A Rooftop Unit?


These are set at specific positions to either allow more or less airflow into the unit. These can be manual or modulating depending on the manufacturer.

Heating and Cooling Services Technician Replacing a Filter in a Roof top Unit


These help to filter the air before it enters the system. The size of the unit, frequency of use and outdoor conditions will determine how frequently these filters should be changed.


This can be a cooling coil, a heating coil or both. As the air enters the unit, it is run over one of these coils. This conditions the air before it is brought into the building.

Heat Exchangers

These help to improve the efficiency of the unit. Heat exchangers allow for preheating or cooling of incoming outside air by running it in close proximity to conditioned exhaust air leaving the building.

FanIllustration of an air blower with labeled components and side view.

Also known as an air blower, these are what pump the air through the ducting and into the facility. These are most commonly centrifugal fans.

Heat Pump

These pump refrigerant through the coils to heat or cool the air. In some units, heating and cooling components are separate. Compressor and an AC cooling system are then used to cool coils. The heating component then produces heat through the use of electrical or gas.

Your Rooftop Unit Maintenance Checklist

Performing maintenance on your rooftop unit is important. Use these quarterly, and semi-annual and annul maintenance checks to ensure your unit is in good shape.

Semi Annual Maintenance Checks for RTU’s:

  • Technician looking over boiler log sheets as he examines a boiler.

    Check power supply operation

  • Measure volts/amps of condenser fan motors
  • Check starters and contact surfaces 
  • Check operating temperatures
  • Examine refrigerant charge 
  • Check site-glasses 
  • Check all belts
  • Inspect all safety controls 
  • Check superheat and adjustment 
  • Check hot gas by-pass controls 
  • Inspect head pressure controls 
  • Check all operating controls 
  • Examine and tighten all electrical connections
  • Check compressor efficiency 
  • Check cap tubes/piping for chafing 
  • Look for oil/refrigerant leaks 
  • Check fan sheaves for alignment and wear
  • Check fan-bearing supports 
  • Examine motor supports 
  • Check motor hold-down bolts 
  • Check damper operations 
  • Inspect damper linkages 
  • Check damper motor 
  • Clear drainage of any blockages
  • Replace air filters (Quarterly)
  • Clean Coils (Annually)
  • Inspect Economizer (Annually)

Parts To Carry To Reduce RTU Breakdowns

Carrying back up parts in case of a breakdown is always a good idea. The last thing you want is to be with heat in the winter or cool air in the summer. But what parts should you consider carrying? We recommend:

  • Flame Sensors
  • Ignitors
  • Filters
  • Belts
  • Pressure Switches

We Can Help

Rooftop unit maintenance is important for a number of reasons. For one, because of the units remote location, on the roof, it can be harder to hear early warning signs of equipment issues. Let our expert technicians ensure your system is running efficiently. Give us a call at 1-800-237-3141 or email Our team is here to help! For all of your Commercial HVAC service needs this time of year, call the experts. Our HVAC services include repair, new installs, HVAC parts, HVAC rentals and more.