This is one of the most frustrating calls a property manager can make. The system is on, it never seems to shut off, and the building still feels warm. Why won’t an office cool down when the AC is running nonstop? In almost every case we’ve diagnosed, the unit isn’t undersized. It’s losing capacity somewhere between the rooftop and the room.

Where the cooling is actually going

Dirty condenser coils

A coil loaded with a season’s worth of dust and debris forces the compressor to work harder just to hold its ground. If nobody has cleaned your coils since spring, this is worth checking first, and it’s part of every cooling inspection we run.

A stuck economizer

If the damper that’s supposed to bring in cool outdoor air is stuck open on a hot day, it’s actively fighting your compressor. If it’s stuck closed, you’re missing free cooling and running equipment harder than you need to.

Low refrigerant

A system running low on refrigerant runs constantly but never quite catches up. This is one a technician needs to confirm with gauges, not guesswork.

Conflicting setpoints in the controls

In buildings with a building automation system, we sometimes find heating and cooling calling for opposite things in the same zone. That kind of conflict is invisible unless someone pulls the trend logs.

Why this is easier to diagnose with a BAS in place

Why won’t a building cool down even with the AC running? With an open-protocol BAS like Niagara 4, a technician can pull supply air temperature, runtime, and zone setpoint history before ever stepping on the roof. Without that data, diagnosing the same problem is mostly guesswork and a longer service call.

What to do this week

1. Book a coil cleaning and refrigerant check if it hasn’t happened this season
2. Have someone confirm your economizer dampers are actually moving
3. Pull two weeks of trend data and look for zones that never reach setpoint
4. If the building doesn’t have a BAS yet, this is a good moment to ask what automating your HVAC would actually involve

Alpine HVAC diagnostics across the Golden Horseshoe

Our technicians are cross-trained in both mechanical systems and controls, so we can trace a comfort complaint from the thermostat all the way back to the coil. If your building won’t cool down no matter how hard the AC runs, get in touch and we’ll find out why.