A technical intervention on a Midea system in an urban environment
At AirGreen , we are regularly called upon to work on HVAC systems installed on the roofs of residential and commercial buildings in Montreal. Recently, our team was called upon in Côte-des-Neiges–Notre-Dame-de-Grâce to diagnose a Midea heat pump that was exhibiting irregular performance in heating mode, accompanied by unusual noises during startup.
The outdoor unit, installed on a metal rooftop structure, was exposed to variable weather conditions and a typical urban environment—wind, dust, and temperature fluctuations. These factors, combined with infrequent maintenance, can quickly affect the performance of a Midea system, which is renowned for its reliability.
Initial diagnosis: abnormal noise and reduced performance
Our technician began with a complete visual inspection of the compressor and fan. The reported noise was due to a partial fan imbalance , caused by dust buildup on the blades and slight play in the center shaft. Additionally, the protective grilles showed signs of wear and deformation, indicating that the fan motor needed a thorough inspection.
At the same time, a refrigeration pressure check revealed a slight deficit of R-32 refrigerant , probably due to a micro-leak at a flare fitting. This situation led to a significant drop in efficiency: the unit was unable to reach the target temperature, especially on cooler days.
Steps of repair
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Complete cleaning of the fan and coil :
We removed the protective grille and thoroughly cleaned the blades using a specialized HVAC cleaner. The coil was also washed at low pressure to promote better heat exchange. -
Mechanical readjustment :
The fan has been rebalanced and its motor has received preventive lubrication to eliminate vibrations and residual noise. -
Leak detection and repair :
After nitrogen testing and tracer detection, the microleak was located on an external flare connection. The seal was replaced and tightened according to Midea's specifications. -
R-32 recharge and final calibration :
We performed a precise refrigerant recharge , followed by a complete performance test in heating and cooling mode. -
Drainage and leveling control :
Since the unit was on a roof mount, we also adjusted the plinth leveling to ensure proper condensate drainage.
Results: Restored comfort and extended reliability
After the intervention, the Midea heat pump was operating at full efficiency, with stable performance and complete noise reduction . The client, a co-owner of the building, was pleasantly surprised to find that the system's performance even exceeded that observed during the initial installation.
Our service report included:
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The pressure values before and after recharging ,
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Power consumption measured after cleaning,
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Preventative maintenance recommendations for the coming seasons.
Maintenance Tips for Rooftop Units
Systems installed on roofs, particularly in Montreal and Laval, require special attention:
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Cleaning the coil twice a year (spring and fall)
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Checking the refrigerant charge before the heating season
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Inspection of the metal support to avoid excessive vibration
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Defrost control during periods of intense cold
At AirGreen, we also recommend installing anti-vibration pads and specialized unit covers during the winter to extend the life of Midea, Fujitsu, Gree or Sharp systems.
AirGreen expertise at your service
This intervention in Côte-des-Neiges illustrates our approach: rigor, transparency and attention to detail . Each diagnosis we carry out combines field experience and in-depth technical knowledge of multi-brand HVAC systems.
Whether it is a refrigerant leak , an abnormal noise , a faulty electronic card or a defrosting problem , our technicians are trained to quickly identify and correct the source of the problem.
By choosing AirGreen, you benefit from a local, fast and sustainable service , covering Montreal, Laval, Longueuil, the North Shore and the South Shore .