Repair of a Midea heat pump on a roof in Côte-des-Neiges–Notre-Dame-de-Grâce

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

1. 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.

2. Mechanical readjustment :
   The fan has been rebalanced and its motor has received preventive lubrication to eliminate vibrations and residual noise.

3. 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.

4. R-32 recharge and final calibration :
   We performed a precise refrigerant recharge , followed by a complete performance test in heating and cooling mode.

5. 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:

• The pressure values ​​before and after recharging ,

• Power consumption measured after cleaning,

• Preventative maintenance recommendations for the coming seasons.

Maintenance Tips for Rooftop Units

Systems installed on roofs, particularly in Montreal and Laval, require special attention:

• Cleaning the coil twice a year (spring and fall)

• Checking the refrigerant charge before the heating season

• Inspection of the metal support to avoid excessive vibration

• 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 .