Commercial HVAC equipment works hard. Rooftop units serve open retail floors, offices with changing occupancy and kitchens with heavy heat loads, and they sit exposed to sun, wind, snow and debris all year. A maintenance program keeps them running and lets you plan around them instead of reacting to them. Here is what a planned maintenance visit covers, season by season, and how to set a program up.
Spring: cooling startup
The spring visit gets the cooling side ready before the first hot week:
- Clean condenser coils and inspect evaporator coils for dirt and damage.
- Check refrigerant operating pressures, superheat and subcooling.
- Test capacitors and inspect contactors and electrical connections.
- Measure compressor and fan motor amp draw against nameplate ratings.
- Clean condensate pans and drains and check traps, so water doesn't back up into the unit or the ceiling below.
- Inspect, adjust or replace belts, and check pulley alignment.
- Check the economizer, including damper movement, linkage and sensors, so the unit can use cool outdoor air when conditions allow.
Fall: heating startup
The fall visit focuses on the heating section, whether that is gas heat in a rooftop unit, a furnace or a heat pump:
- Inspect and clean burners, igniters and flame sensors as needed.
- Inspect the heat exchanger for cracks and corrosion.
- Check gas pressure, combustion and flue venting.
- Test safety controls, including limit switches, rollout switches and pressure switches.
- Check the economizer again. A damper stuck open in winter pulls in cold outdoor air, drives up the heating load and leaves the space uncomfortable.
- For heat pumps, check defrost operation and auxiliary heat.
Every visit, and in between
Some items get checked every time a technician is on the roof: filters, belts, thermostat and control operation, and the general condition of the unit, including panels, curbs and roof penetrations where leaks start. Filters usually need changing more often than twice a year. A typical office may run on a quarterly schedule. Restaurants, gyms, warehouses and anywhere with heavy dust, grease or foot traffic may need monthly changes. The schedule should match the building, not a default.
Setting up a maintenance program
A program works best when it starts with good information:
- Inventory the equipment. List each unit with make, model, serial number, age, tonnage, heat type, filter sizes and quantities, and belt sizes. Note which areas each unit serves.
- Sort out access. Roof hatch or ladder, keys, alarm codes, and the hours a technician can be on site without disrupting business or tenants.
- Set the visit schedule. Spring and fall at minimum, with filter visits in between based on how hard the building is on filters.
- Keep the records. Every visit should produce a report with readings, findings and recommended repairs. Over time those records show which units are aging out.
- Plan capital replacements. Use the age and condition of each unit to build a replacement plan for the next few years, so nothing catches you off guard.
JM Mechanical works on light commercial HVAC, including rooftop units and split systems, for business owners and property managers. Call (513) 667-8484 or request service online to set up a maintenance program for your building.