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Commercial · Commercial Air Conditioning RepairCommercial Air Conditioning Repair
Commercial air conditioning repair is, most of the time, one of six faults: a contactor, a capacitor, a condenser fan motor, a plugged condenser coil, a refrigerant leak, or lost phase on a three-phase compressor. The first four are normally fixed in one visit. The decision rule for the expensive one is age: when a compressor fails on a unit older than 12 to 15 years, price a replacement beside the repair before approving either.
Start with the parts that fail most. The contactor is the relay that switches the compressor and condenser fan on, and its contacts pit and weld after years of starts; the capacitor that helps single-phase motors start loses capacity in heat and tends to quit on the hottest day of the year. A condenser fan motor that seizes lets head pressure climb until the unit trips on its high-pressure switch. All three produce the same complaint from inside the building: the fan blows but the air is warm.
A plugged condenser coil is the seasonal one. Cottonwood seed flies in late May and June and mats across the outdoor coil of a rooftop unit like felt, and plazas near creek valleys and treed lots get it worst. The unit runs hotter, draws more current, cools less and eventually trips; washing the coil from the inside out restores it. If your units trip only on the first hot afternoons of the year, look at the coil before anything else.
Three-phase compressors add a failure that houses do not have. If one leg of a 208 V or 575 V supply drops, or two legs are swapped after electrical work, a scroll compressor can overheat or run backward and destroy itself in short order. A phase monitor is a small relay that watches all three legs and refuses to start the unit when one is missing, low or out of sequence. Where a unit has no monitor and has already lost a compressor, adding one costs far less than the compressor it protects, and anything upstream of the unit's own disconnect is work for a licensed electrician under ESA rules.
Refrigerant rules shape the repair. R-22 units can be serviced only with reclaimed refrigerant, which is scarce and priced accordingly; new equipment is moving from R-410A to R-454B, a mildly flammable A2L refrigerant, and the two cannot be mixed or swapped in an existing unit. Ontario Regulation 463/10 requires a leaking system to be repaired before refrigerant is added, with the leak test and the amounts recorded. A yearly top-up with no leak search is not a repair, and it is not what the regulation allows.
In Ontario the refrigerant side of a commercial unit is restricted work: it takes a 313A refrigeration and air conditioning systems mechanic who also holds an ODP card, and you are entitled to see both. Packaged units are covered in more depth under rooftop unit service, and older machines under R-22 air conditioner repair. For planned work and replacements see commercial HVAC and what a commercial rooftop unit costs. Same-day service depends on where the trucks are, so call early and we will tell you straight whether today is possible.
Equipment we install and service
Cooling, heating and the fan in one cabinet on the roof, from small single-phase units over a shop to multi-stage three-phase units over a plaza. Contactors, capacitors, condenser fan motors, belts and dirty coils are the routine repairs; compressors and leaking coils are the costly ones.
A condensing unit outside or on the roof and an air handler or furnace coil inside, joined by a refrigerant line set. Long line runs add leak points at flare and braze joints, and the indoor coil's drain is a frequent source of ceiling stains. Installation questions are on the commercial split systems page.
Wall or ceiling heads that cool one room year-round. They fail on dirty indoor coils, blocked drains and, in winter, low-ambient operation the unit was never set up for.
Thermostats, phase monitors, high- and low-pressure switches, and the time delays that stop a compressor from short-cycling. A pressure switch that keeps tripping is reporting a real fault — airflow, charge or a fan — and jumping it out is how compressors die.
What goes wrong in these buildings
- The fan is blowing but the air coming out of the diffusers is warm.
- It trips every afternoon around three and works again after we reset it.
- Someone adds refrigerant every spring and it is low again by August.
- One compressor already died and nobody could tell me why.
- The unit takes R-22 and I keep hearing it cannot be fixed.
- The tenant is calling hourly and the landlord says the rooftop is our problem.
How it works
Voltage on all three legs, amp draw, capacitor value, pressures and temperatures, and a look at both coils. You get the fault and the evidence for it, not a guess followed by a parts list.
Common electrical parts and motors are on the truck and go in on the first visit. Leaks are located and repaired before any refrigerant is weighed in, and the amounts are recorded on the service report.
For a compressor or coil on an older unit we put the repair price beside a replacement quote, including crane and curb adapter if they are needed. The rule we apply: over 12 to 15 years old, or charged with R-22, a compressor is rarely worth buying.
Common questions
Can you come the same day?
Often, but we will not promise it before checking the schedule. Calls placed early in the day have the best chance, and a failure affecting a server room, clinic or kitchen is moved ahead of a warm office. If a truck cannot reach you that day, we tell you so on the phone and suggest what to switch off to protect the compressor in the meantime.
How much does commercial AC repair cost?
Each repair is priced in writing on site before work starts. A small single-phase rooftop unit uses much the same contactors, capacitors and fan motors as a house, so those are the smaller bills; three-phase motors, compressors, refrigerant quantity and crane or lift access push larger units higher. The diagnostic visit establishes which kind of repair you are facing.
Is it worth repairing an R-22 unit?
For electrical parts, fan motors and cleaning, yes — those repairs do not open the refrigerant circuit. For a leak or a compressor, usually no. R-22 is available only as reclaimed stock, so every recharge is expensive and gets more so, and the unit is old enough that the next failure is close. That money is better counted toward a replacement.
Why does the unit keep tripping on hot afternoons?
High head pressure. In the hottest hours the condenser has to reject the most heat, and a matted coil, a weak fan motor or a failing capacitor leaves no margin, so the high-pressure switch opens. Resetting it works until the next hot afternoon. The fix is cleaning the coil and testing the fan and capacitor, not a bigger unit.
Related
Keep the building running.
One licensed team for installs, maintenance contracts and 2 AM calls.