Rooftop Not Cooling — Quick B2B Guide

When a rooftop stops cooling commercial or institutional spaces, the impacts range from comfort to goods preservation to process conditions. The issue often comes down to a gap between demand (thermostat, programming, BMS) and the unit’s capacity, or a fault on the refrigeration or airflow side.

What factors most commonly explain the lack of cooling?

Among frequent causes: incorrect setpoint or mode, limitation from an airflow imbalance (filters, dampers), compressor or condenser fan fault, refrigerant issue or electrical control problem. A rooftop inspection with measurement tools is needed to confirm — this is not a first-level task from the office alone.

What can be checked from inside the building or without restricted access?

Confirm the cooling demand (setpoint, schedule, not accidentally in heating mode), note any visible alarms on the interface if available, and report any overheated zones or abnormal airflow to your maintenance team. Avoid opening electrical or refrigerant panels without training: voltage and pressurized fluids present hazards.

When should you consult an HVAC professional?

If the situation persists after basic verification, or as soon as unusual noise, a recurring alarm or a multi-zone failure appears. Montréal Combustion supports commercial buildings across Greater Montréal and the shores for commercial air conditioning, structured diagnostics and preventive maintenance of RTUs. Contact: 450-473-0909 to schedule a service call or consultation.

Frequently Asked Questions

Can a dirty air filter alone explain the loss of cooling?

A clogged filter reduces airflow and can degrade performance, but it is not the only possible cause. Incorrect refrigerant charge, an electrical fault or a condenser problem requires diagnosis by a qualified technician.

Should I go up on the roof to inspect the unit?

Rooftop access and mechanical zones are subject to safety rules and authorization requirements. Leave close-up visual inspection and measurements to trained and equipped personnel.

Can programming or the BMS simulate a breakdown?

Yes: schedules, setpoints, economy mode or remote lockout can limit cooling. Verify visible parameters within your scope before escalating — without modifying critical settings without approval.