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Réparation d’une thermopompe murale Midea à Sainte-Dorothée
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Repair of a Midea wall-mounted heat pump in Sainte-Dorothée

A heat pump that was no longer cooling properly: rapid diagnosis and repair by AirGreen

At AirGreen , we work daily throughout the greater Montreal area to diagnose and repair residential HVAC systems that are losing performance. Recently, our team was called to Sainte-Dorothée (Laval) for a Midea wall-mounted heat pump that, according to the customer, "was no longer blowing cold air like it used to."

Our goal: to identify the cause of the problem and restore optimal comfort , while ensuring maximum energy efficiency.

Initial observation: lukewarm air despite the cooling instruction

Upon arrival, we performed a visual and functional check of the indoor unit. The outdoor compressor started up fine, but the air coming out of the diffuser seemed lukewarm.
To confirm this impression, our technician used a professional infrared thermometer , measuring the blowing temperature at 11.0 °C . Such a value, much higher than what it should be in air conditioning mode (normally between 6 °C and 8 °C), indicated a partial loss of thermal efficiency .

Step 1: Check Filters and Airflow

We started by inspecting the air filters . They were slightly dirty, which could reduce airflow, but not so much that it caused such a significant loss of cold. After a thorough cleaning , we restarted the system to observe any changes: the outlet temperature remained stable around 10.8 °C.
➡️ Conclusion : the problem was not with the airflow.

Step 2: Inspection of the refrigeration circuit and pressure

We then proceeded to check the refrigerant pressures at the outdoor compressor. The observed values ​​indicated a pressure slightly lower than normal , suggesting a small refrigerant leak (R410A) .
This hypothesis was confirmed by a leak detection test using an electronic detector - the origin was located at a slightly loose flare fitting at the connection between the liquid line and the outdoor unit.

Step 3: Repair and recharge the refrigerant

We have :

  • Tightened the flare fitting and replaced the gasket.

  • Performed a nitrogen test to check the circuit's performance.

  • Pulled a complete vacuum from the system.

  • Recharged the refrigerant to the nominal charge specified by Midea.

Once the procedure was completed, the heat pump was restarted. After ten minutes of operation, the temperature measured at the diffuser dropped to 6.7°C , confirming the return to optimal performance .

Step 4: Check the drain and temperature sensor

We also took advantage of the intervention to:

  • Clean the condensate tray and drainage pipe to prevent future buildup.

  • Check the evaporator temperature sensor , a component sometimes responsible for poor interior temperature control.

Everything was in order. The customer noticed an immediate difference in the freshness and power of the airflow.

Final result: restored comfort and optimized energy efficiency

Thanks to a quick and methodical intervention , the customer's Midea heat pump is now operating at full capacity. The indoor temperature has become stable again, and the system displays a difference of 18 to 20 °C between the intake air and the supply air , a sign of ideal performance .

The client was also advised on:

  • The importance of cleaning filters every 4 to 6 weeks .

  • The need for annual preventive maintenance to prevent minor leaks and ensure compressor longevity.

Why use AirGreen?

At AirGreen, we put our expertise in Midea heat pumps and other recognized brands (Fujitsu, Gree, Sharp, Mitsubishi, LG, etc.) at the service of homes in Laval, Montreal, the North Shore and the South Shore .
Our certified technicians:

  • Accurately diagnose each anomaly.

  • Repair efficiently while respecting HVAC safety standards.

  • Offer sustainable and economical solutions.

Each intervention results in restored performance, reduced energy consumption and assured comfort .

In summary

This intervention in Sainte-Dorothée (Laval) perfectly illustrates our approach:
➡️ a rigorous diagnosis ,
➡️ targeted repair ,
➡️ and a measurable result .

Is your wall-mounted heat pump no longer blowing cold enough?
Contact AirGreen , your trusted partner for any repair, installation or maintenance of residential and commercial HVAC systems in the greater Montreal area.