If you're responsible for a commercial HVAC system, chances are you've been caught off guard by an unexpected failure, just when your tenants or team need heat or cooling most.
That’s why more building owners are turning to preventative maintenance, but if you’ve never had one done, you might wonder: What exactly happens during a visit?
At Harold Brothers, over the past 17 years in business, we’ve performed thousands of commercial PM visits across Massachusetts. We don’t just replace filters, we uncover hidden issues, test performance, and help you plan smart repairs before emergencies arise. We have helped companies cut costs by up to 20% by just adding in standard maintenance practices.
In this article, we’ll walk you through the exact steps our techs follow, with real-life examples from the field, so you know what to expect before we even arrive.
Before opening equipment, your technician checks in with you or your onsite contact. They ask questions such as whether there are hot or cold spots, if there have been unusual noises, or if anything seems off since the last visit. These answers help guide the work that follows. Learn more about the schedule of visits with a Preventative Maintenance Contract in our PM Contract Timeline.
Once we get started, we closely inspect your equipment, both inside and out. We look for:
We then clean what needs cleaning. This could include coil washing, clearing debris, vacuuming burners, or other seasonal tasks.
During a visit to a Boston retail shop, Tyler inspected a heat pump system and rooftop unit. The system had been running for a while without much attention, and there was a surprising amount of dust resting on the ductwork that caught his eye immediately.
He cleaned both the indoor and outdoor coils, helping the system breathe more easily and improving output. When he checked performance, the system delivered a healthy 20 degree Fahrenheit temperature rise in heating mode, confirming that it was moving heat effectively.
Tyler explained that the system was functioning well, but the dust buildup suggested that duct cleaning would be a smart next step. There was nothing failing at that moment, but taking that step would help protect efficiency and indoor air quality.
This is typical of preventative maintenance. The equipment is cleaned and tuned, and you receive helpful guidance to avoid future problems.
Next, we check and replace filters if needed. Clean filters protect sensitive equipment, improve airflow, reduce energy use, and support better indoor air quality. You can see a reduction in energy use of up to 25% when you make sure you are changing out your filters.
If the proper filters are not on site, we document it and schedule a return visit. We will never force an incorrect filter.
Your HVAC system contains many moving and electrical parts that must work together. During this stage, we check:
We tighten loose hardware, correct small issues where possible, and document any recommended repairs. Even new equipment needs this regular check in and tune up. Make sure to check your warranty information, because regular preventative maintenance might be a stipulation for warranty coverage.
At a fitness center with multiple rooftop units, Tyler arrived expecting a routine PM. The equipment was older but still operating, so nothing seemed alarming at first.
Once he began, the larger story became clearer. He discovered that two of the units had heat exchangers so badly rotted that they could not safely produce heat. One unit needed a new inducer motor assembly. Another cooling circuit was flat on refrigerant, likely because of a leak in the condenser coil.
Cooling still functioned, but heat operation was unsafe. Tyler shut off gas service where appropriate and documented photos, data, and notes.
From the outside, the units looked normal. The preventative maintenance visit revealed serious internal issues long before winter weather made heat essential. Because PM caught these issues early, the gym could plan replacements and repairs comfortably.
Throughout the visit, your technician records operating data including model and serial numbers, heating and cooling temperature changes, compressor amp draws, and safety responses.
This information helps track performance over time. Small changes can indicate developing issues before failures occur.
Once inspection and cleaning are complete, we test safeties and verify proper heating or cooling operation. If something is unsafe, we will not leave the equipment running.
During a fall boiler maintenance visit, Corey arrived to perform routine service. The boiler was firing correctly, temperatures showed a healthy spread, and all heating zones responded properly. He vacuumed the burners, confirmed safeties were working, and checked components for wear.
During the piping inspection, he noticed a leaking three quarter inch ball valve on the return side of the boiler. He also found that the expansion tank was about 12 years old, nearing the end of its expected service life.
The boiler was still heating the building, but both issues would have caused problems eventually. Because Corey found them during PM, the owner could schedule proactive repairs instead of dealing with a mid-season leak or no-heat emergency.
This is the value of preventative maintenance. Nothing had broken yet, but the customer avoided an unexpected failure.
Preventive maintenance helps you avoid surprise breakdowns, extend equipment life, reduce energy costs, improve air quality, and plan for future repairs and upgrades.
Even when equipment appears to be operating normally, PM provides documentation and a clear picture of system performance.
Preventive maintenance helps you avoid surprise breakdowns, extend equipment life, reduce energy costs, improve air quality, and plan for future repairs and upgrades. Typical pricing for a PM can range anywhere from $5,000 to $20,000+, depending on system size, building type, and visit frequency. To understand key pricing factors and what’s included, explore our guide to commercial HVAC preventative maintenance costs.
At the end of the day, commercial HVAC surprises are rarely cheap and never convenient. Whether it’s a failing heat exchanger or poor airflow that affects your tenant comfort, the earlier you catch the issue, the better.
Now that you’ve seen what a full Harold Brothers PM visit includes and how we uncover problems before they escalate, you’re in a better position to plan your next visit with confidence.
Your next step? Request information on PM’s now, before the next seasonal demand puts pressure on your system.
At Harold Brothers, we’ve helped hundreds of facility managers stay ahead of HVAC emergencies with expert-level inspections, smart documentation, and proactive care. Let’s help you do the same.