Technical intervention on a commercial roof in rainy weather
At AirGreen , we are often called upon to intervene in demanding technical environments. On this day, our team traveled to Montreal West for an urgent repair of a Gree MultiZone system installed on the flat roof of a commercial building. The client, a building manager, had noticed that two air-conditioned zones were no longer responding to wall controls. In the midst of a period of continuous rain, the intervention required caution, expertise, and responsiveness.
Initial inspection: understanding the nature of the failure
Upon arrival, our team secured access to the roof and performed a visual inspection of the Gree outdoor units . The system, consisting of two compressors connected to several wall-mounted indoor units, showed signs of excessive condensation around the refrigeration ducts and slightly exposed power wiring .
Preliminary analysis revealed:
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No communication between the main board and some indoor units.
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Partial oxidation on the control module connectors.
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Accumulation of water under the insulation of refrigeration pipes , caused by prolonged infiltration.
Detailed diagnosis with specialized instruments
Our technicians used a Gree electronic communication analyzer , combined with a digital manifold , to confirm the exact nature of the fault. After several tests, the diagnosis was clear:
a short circuit in the communication cable connecting the two outdoor units, probably exacerbated by humidity.
We then have:
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Disconnected the faulty cable and measured the resistance between the signal wires.
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Cleaned and dried all connections with compressed air and dielectric agent.
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Replaced the damaged segment with a shielded cable approved for outdoor use.
A controlled and secure restart
Once the repairs were completed, we restored power and ran a full synchronization test between the MultiZone system's master and slave modules. The Gree diagnostic screen now displayed normal status codes (F0) , confirming that communication had resumed.
The compressor started without delay, and we observed:
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Stable pressure on the refrigerant circuits.
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Progressive thermal balancing in the affected areas.
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Standardized sound performance , without vibrations or crackling.
Despite the persistent rain, our team protected the equipment with temporary waterproof tarpaulins to ensure safe and compliant commissioning.
Result: comfort and performance restored
The Gree MultiZone system has regained its original efficiency , once again ensuring optimal comfort for the building's occupants. The manager particularly appreciated our ability to intervene quickly despite the difficult weather conditions , without interrupting the business activities on the ground floor.
AirGreen Technical Recommendations
In order to avoid this type of breakdown in the future, we have made several recommendations to the customer:
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Insulate and protect all outdoor cables exposed to the weather.
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Install waterproof sleeves on electrical connections.
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Schedule an annual preventive inspection , especially before wet seasons.
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Check the fastening of the refrigeration ducts after each winter to prevent wear due to freezing and thawing.
At AirGreen, we emphasize proactive maintenance of MultiZone systems , especially on commercial rooftops, where environmental conditions can accelerate the deterioration of electronic components.
AirGreen expertise at the service of professional buildings
Our team operates daily throughout the metropolitan area — Montreal, Laval, Longueuil, the North Shore and the South Shore — for the maintenance and repair of Gree, Fujitsu, Sharp, Midea, Bosch systems and many others .
Our technicians are trained to work at heights and are familiar with safety protocols for flat roofs, whether for commercial buildings, residential buildings, or schools.
With our well-stocked local warehouse and advanced diagnostic tools , we guarantee fast, durable repairs that meet manufacturer standards.