When performance and reliability meet at height
At AirGreen , we know that a MultiZone HVAC system installed on a flat roof must cope with demanding conditions: extreme heat in the summer, bitter cold in the winter, and constant exposure to the elements. This is exactly the type of challenge we encountered during this service call in Pointe-Claire , on Montreal's West Shore.
The context of the intervention
The building in question: a modern, multi-story condominium equipped with several Midea MultiZone outdoor units located on the roof. These compressors power various wall-mounted units located throughout the apartments, ensuring the individual comfort of each occupant.
The building manager contacted us after noticing that some areas were no longer responding properly to the control, with indoor units blowing lukewarm air despite the air conditioning request . Additionally, an unusual noise was coming from one of the outdoor units.
Detailed on-site diagnosis
Our technicians went up to the roof for a complete inspection of the Midea outdoor modules . From the first check, several clues caught our attention:
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Traces of oil around one of the refrigeration connections: possible sign of a micro-leak of R-32 refrigerant .
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Swollen capacitor on a power board: potential electrical problem.
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Abnormal vibrations on one of the compressors when it tried to start.
Using our electronic leak detector , we confirmed a minor leak at a flare fitting . This type of leak, although slight, disrupts the pressure in the circuit and causes an imbalance throughout the MultiZone system.
Steps of repair
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Complete refrigerant recovery : in accordance with environmental standards, we recovered the remaining gas in an approved cylinder.
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Replacement of the flare fitting and addition of a new copper gasket to ensure a perfect seal.
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Upgraded power wiring and replaced capacitor on affected unit.
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Extended vacuum (500 microns) to eliminate all traces of humidity.
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Complete recharge in R-32 , according to Midea specifications.
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Synchronized performance test across all zones : measurement of supply and return temperatures in each condo.
Final result
After these interventions, the indoor units resumed optimal operation , providing constant cold air and rapid response to commands. The defective compressor regained its sound and vibration stability.
The manager, reassured, particularly appreciated our detailed maintenance report and prevention recommendations :
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Semi-annual check of circuit pressure.
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Regular cleaning of outdoor coils.
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Preventive tightening of fittings before the hot season.
Why these rooftop systems require special attention
Flat roof installations like this are becoming increasingly common in condo buildings in Montreal and the South/North Shore , but they require rigorous technical expertise :
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Constant wind and horizontal rain can accelerate corrosion of connections.
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Exposed refrigeration cables experience extreme thermal variations.
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The weight and vibration of the compressors require stable support - hence the importance of the treated wood bases visible in the photo.
Our AirGreen teams are specially trained to intervene in this type of environment. We provide not only immediate repair , but also a comprehensive vision of the sustainability of the HVAC system .
Recognized expertise in Pointe-Claire and beyond
This case perfectly illustrates AirGreen's expertise in repairing Midea MultiZone systems in Montreal, Laval, Longueuil, the North Shore and the South Shore . Whether it's micro-leaks , electronic failures or pressure imbalances , our technicians diagnose, repair and optimize each installation to extend its lifespan.
We believe that a well-maintained HVAC system means lasting comfort, energy efficiency, and peace of mind—whether the unit is installed in a single-family home or on the roof of a residential building.
In summary , this intervention in Pointe-Claire demonstrates our ability to solve complex problems in difficult environments. Thanks to our rigor and our mastery of Midea MultiZone technologies, we restored total comfort to the occupants while ensuring the long-term reliability of the system.