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Réparation d’un système CVAC Zephyr sur toit plat à Saint-Laurent
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Repair of a Zephyr HVAC system on a flat roof in Saint-Laurent

A technical service call on a commercial roof

At AirGreen , we regularly receive calls from commercial clients experiencing breakdowns with Zephyr HVAC systems installed on flat roofs. This was recently the case in Saint-Laurent , where a company contacted us after experiencing a sudden loss of performance from its outdoor unit located on the roof of its industrial building. The indoor air was no longer cooling effectively, and the temperature was rising dangerously in the offices despite the thermostat being set at 22°C.

Diagnosis of the problem: a condenser failure

Our certified technicians quickly arrived on site to perform a complete inspection of the Zephyr system . Upon arrival, a visual observation revealed several clues:

  • Accumulation of dust and debris on the condenser fins.

  • Abnormal noise coming from the outdoor unit fan.

  • Irregular refrigerant pressures on gauges.

After isolating the system, we carried out a complete electrical and mechanical check :
The fan motor was seized, preventing heat dissipation from the condenser. In addition, the thermal overload had caused the compressor to trip.

Repair intervention: ventilation, cleaning and recommissioning

Our experts replaced the faulty fan motor with a genuine Zephyr part and performed a thorough cleaning of the condenser coils using a biodegradable cleaner specific to rooftop systems.
Next, a nitrogen leak test was performed to ensure the refrigeration circuit was leak-proof. No leaks were detected.

We then have:

  1. Readjusted the R-410A refrigerant charge , according to the manufacturer's recommended operating pressures.

  2. Checked electrical continuity and control relays .

  3. Reset the compressor and validated the start and stop cycles.

  4. Tested the blowing performance in the interior ducts.

After these interventions, the Zephyr system regained its full capacity: blowing at 12°C in air conditioning mode and perfect pressure stability.

The importance of regular maintenance on flat roofs

HVAC systems installed on commercial roofs , as is often the case in Saint-Laurent and other industrial sectors of Montreal , are particularly exposed:
Wind, dust, debris, temperature fluctuations and water infiltration can significantly reduce their lifespan.

We always recommend bi-annual preventative maintenance , including:

  • Cleaning the coils.

  • Checking the refrigerant charge.

  • Inspection of electrical wiring and mechanical components.

  • Checking the condensate flow.

  • Tightening connections and testing pressure switches.

This proactive approach helps avoid costly service interruptions, especially for businesses where employee comfort and IT equipment performance depend on stable climate control.

AirGreen expertise at your service

Each intervention carried out by our team is documented and complies with the standards of the Quebec Building Code and environmental requirements for refrigerants.
We have a complete inventory of parts for the majority of brands used in Greater Montreal: Zephyr, Gree, Fujitsu, Midea, Trane, Sharp, Goodman , and many others.

Thanks to our certified technicians, we work on commercial roofs in Saint-Laurent as well as in residential buildings in Plateau-Mont-Royal , Laval or the South Shore .

Result: comfort restored and system optimized

After the repair, the customer noticed an immediate improvement:

  • stabilized interior temperature;

  • reduced electricity consumption;

  • external noise eliminated;

  • regular operating cycle.

This type of intervention demonstrates AirGreen's expertise: diagnosing quickly, intervening effectively and extending the lifespan of HVAC systems in urban environments.

Why choose AirGreen?

  • Certified technicians trained on the latest HVAC technologies.

  • Fast service throughout Greater Montreal, 24/7 in case of emergency.

  • Complete transparency on costs, diagnoses and recommendations.

  • Sustainable solutions focused on energy efficiency and reliability.

At AirGreen , we believe that a well-maintained system is a profitable long-term investment.
Our commercial clients in Saint-Laurent, Montreal and throughout the North and South Shores can count on us to keep their HVAC systems operating at peak performance.