It's 30°C, a tenant is calling, and the AC isn't cooling. Before you authorize an after-hours dispatch at triple the daytime rate, there are eight checks a property manager can run in ten minutes — several of which resolve the problem outright. Here's the exact sequence our techs would want you to walk through first.
These checks are visual and at the thermostat/panel level only. Do not open electrical panels, handle refrigerant, or climb onto a roof without proper training and fall protection. When a check points to an electrical or refrigerant problem, that's the signal to call a technician — not to go further yourself.
The 8 checks, in order
1. Thermostat / controls
Obvious, but it's the number one false alarm. Confirm the thermostat is set to Cool, the setpoint is below the current room temperature, the mode isn't on "fan only," and any scheduling or override hasn't locked it out. On a BAS-controlled building, check the controls haven't put the unit into an unoccupied or economizer-only mode.
2. Power and breakers
Is the unit actually running? If it's completely dead, a tripped breaker or blown fuse is common. Check whether the breaker has tripped — if it trips again immediately after reset, stop and call a technician, because that's an electrical fault, not a nuisance trip.
3. Air filter
A severely clogged filter is the single most common cause of "running but not cooling." It chokes airflow across the coil, dropping capacity and eventually freezing the coil. If the filter is grey and packed, replace it — this alone fixes a meaningful share of calls.
4. Frozen evaporator coil or refrigerant lines
If you see ice on the indoor coil or the refrigerant lines, the unit is frozen. Turn cooling off (run the fan only to help it thaw) — running a frozen unit can damage the compressor. A freeze usually traces to restricted airflow (dirty filter) or low refrigerant. If it refreezes after a filter change, it's a refrigerant/airflow issue for a technician.
5. Outdoor condenser airflow
For rooftop or split-system condensers, check the outdoor coil is clear — leaves, cottonwood, debris, or something stacked against it. A blocked condenser can't reject heat, so the system runs but doesn't cool. Clearing obstructions and gently cleaning the coil surface can restore cooling.
6. Condensate overflow / float switch
Many units have a safety float switch that shuts off cooling if the condensate drain backs up (to prevent water damage). A clogged drain can therefore stop cooling entirely. If the drain pan is full, the drain is likely clogged.
7. Unit alarms / lockouts
Check the unit's control board or the BAS for any alarm or lockout — high-pressure trips, low-pressure trips, or flame/ignition faults on units with gas heat. A high-pressure lockout often points to the condenser airflow issue from check 5.
8. The obvious scope question
Is it one space or the whole building? One zone usually means a single unit or thermostat; the whole building points to central plant (chiller, pumps, cooling tower) or a building-wide controls/power issue. This tells the technician where to start and whether it's a true emergency.
Quick fix vs. real emergency
| Likely a quick fix | Call a technician now |
|---|---|
| Thermostat setting / mode | Breaker trips repeatedly |
| Clogged filter | Ice that returns after filter change |
| Blocked condenser coil | Refrigerant smell or visible leak |
| Full condensate pan (clear the drain) | Burning smell or unusual noise |
| Reset after a one-time nuisance trip | Whole-building loss of cooling |
What emergency AC repair costs — and how to avoid it
After-hours commercial AC repair in the GTA typically runs $350–$650 for the first hour plus parts, at 2–3x daytime rates. A capacitor is cheap; a refrigerant leak repair or compressor replacement is not. Two things reduce this cost dramatically over a cooling season: running the checks above before dispatching, and having an all-inclusive maintenance contract where emergency dispatch is already included rather than billed at premium rates.
The ideal isn't troubleshooting faster — it's getting the alert before the tenant does. Buildings with live monitoring see a unit's cooling capacity dropping or a high-pressure trip the moment it happens, so a technician is dispatched before anyone's uncomfortable. The "AC not cooling" call stops being a surprise.
Cooling emergency right now? We dispatch 24/7.
PanCanAir runs 24/7 emergency dispatch for GTA commercial and high-rise buildings. If you've run the checks and still have no cooling, call us — fast response, real technicians.
Call (437) 410-2100 →Frequently Asked Questions
Why is my commercial AC running but not cooling?
Most often: a clogged filter, dirty condenser coil, low refrigerant, a failed capacitor/contactor, a tripped high-pressure safety, or a frozen evaporator coil. Start with the filter, thermostat, and outdoor condenser airflow; refrigerant and electrical issues need a technician.
What should I check before calling for emergency AC repair?
Thermostat set to cool and below room temp; power on and breaker not tripped; filter not clogged; outdoor condenser clear; no ice on coil/lines; no active alarms. These five-minute checks resolve many 'no cooling' calls and can save an after-hours visit.
Is a frozen AC coil an emergency?
Turn cooling off and let it thaw (fan-only helps) — running a frozen unit can damage the compressor. Freezing is usually a dirty filter or low refrigerant. If it refreezes after a filter change, call a technician.
How much does emergency commercial AC repair cost in Toronto?
Typically $350–$650 for the first hour plus parts, at 2–3x daytime rates. A capacitor is cheap; refrigerant or compressor work is far more. Running the basic checks first — and having a contract that includes emergency dispatch — saves real money.