Commercial HVAC problem and diagnostic guides
Identify useful observations, understand likely system categories, and prepare for qualified diagnosis without unsafe electrical, refrigerant, combustion, pressure, or controls work.
Commercial RTU Not Cooling
A packaged rooftop unit runs or receives a cooling call but does not maintain the served space.
Review diagnostic guide →Commercial RTU Short Cycling
The rooftop unit starts and stops more often than the space load and documented control sequence require.
Review diagnostic guide →Commercial HVAC Compressor Failure
A compressor will not start, trips, overheats, operates abnormally, or can no longer produce expected capacity.
Review diagnostic guide →Commercial HVAC Economizer Failure
Outdoor-air dampers, sensors, actuators, or sequence do not provide the intended ventilation or cooling operation.
Review diagnostic guide →High Static Pressure in Commercial HVAC
The air system requires excessive pressure, delivers poor airflow, produces noise, or operates outside fan and equipment expectations.
Review diagnostic guide →Commercial VAV Box Not Working
A variable-air-volume terminal does not deliver or regulate the airflow or heat required by its zone.
Review diagnostic guide →Building Automation System Not Communicating
Controllers, equipment, or supervisory software lose communication, data, commands, trends, or operator visibility.
Review diagnostic guide →Commercial Chiller Alarm
A chiller reports an active alarm, warning, trip, lockout, or abnormal operating condition.
Review diagnostic guide →Commercial Chiller Low Flow
A chiller or plant reports inadequate evaporator or condenser-water flow or operates with unstable flow.
Review diagnostic guide →Commercial Cooling Tower Overflow
A tower basin, equalizer, overflow, drain, or makeup system releases or retains water outside normal operating behavior.
Review diagnostic guide →Commercial HVAC Refrigerant Leak
A commercial system has confirmed or suspected refrigerant loss, oil staining, reduced capacity, alarms, icing, or repeated low-charge history.
Review diagnostic guide →Commercial Building Too Humid
Indoor humidity remains above facility targets, causing discomfort, condensation, odors, material concerns, or process risk.
Review diagnostic guide →Uneven Temperatures in a Commercial Building
Zones served by the same or connected HVAC systems experience persistent hot, cold, or unstable conditions.
Review diagnostic guide →High Commercial HVAC Energy Bill
HVAC-related demand or consumption rises without a clear business, weather, occupancy, or production explanation.
Review diagnostic guide →Commercial HVAC Breaker Tripping
A breaker or protective device serving commercial HVAC equipment opens during startup or operation.
Review diagnostic guide →Commercial Air Handler Low Airflow
An air handler delivers less air than required for capacity, ventilation, pressure, or zone operation.
Review diagnostic guide →Commercial HVAC Controls Offline
A unit controller, thermostat, sensor network, or local HVAC control is powered down, unreachable, unresponsive, or no longer exchanging commands.
Review diagnostic guide →Commercial Tenant Comfort Complaints
Occupants report recurring hot, cold, humid, drafty, noisy, stale, or unstable conditions that routine setpoint changes do not resolve.
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