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Appel de service pour une thermopompe murale Midea à Sainte-Dorothée
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Service call for a Midea wall-mounted heat pump in Sainte-Dorothée

A drop in performance identified thanks to a precise AirGreen diagnosis

At AirGreen , we know that an efficient wall-mounted heat pump relies on a perfect balance of installation, maintenance, and regular monitoring. This service in Sainte-Dorothée (Laval) perfectly illustrates our methodical approach: a customer contacted us after noticing that their Midea heat pump was no longer cooling as well as before, despite a functioning indoor fan.

When we arrived, the ambient temperature in the living room was 23.3°C , but the air blown by the wall unit did not drop below 17.5°C , a difference too small for a system in air conditioning mode.

Symptoms and initial observations

The client mentioned:

  • Slow and uneven cooling of parts;

  • A louder noise from the external compressor ;

  • Slightly higher than usual power consumption ;

  • No error code on the remote.

These signs pointed our diagnosis towards a loss of efficiency of the refrigeration circuit or a partial lack of refrigerant .

Diagnosis carried out by our AirGreen technicians

Our certified technicians followed a rigorous process to identify the exact cause:

1. Checking the internal operation

  • Midea wall unit inspection: directional flap, air filter, temperature sensor.

  • Airflow control: The indoor fan was operating normally, without obstruction.

2. Blowing temperature measurement

Using a professional infrared thermometer , we measured a temperature of 17.5°C at the outlet – insufficient for a unit in good condition, where we should obtain between 9 and 13°C in air conditioning mode.

3. Checking the outdoor condenser

When inspecting the outdoor unit, we observed:

  • A slight accumulation of dust on the condenser;

  • Properly insulated refrigeration pipes;

  • No visible signs of oil leakage.

We then connected our digital pressure gauges to analyze the circuit pressure.

4. Analysis of the refrigeration circuit

The readings indicated a lower than normal suction pressure , confirming a partial loss of R-410A refrigerant . An inspection using our electronic leak detector identified seepage at the liquid line flare fitting, likely improperly tightened after previous maintenance.

Repair carried out

Our technicians proceeded as follows:

  1. Safe recovery of residual refrigerant in accordance with environmental standards (EPA).

  2. Complete cleaning of the fitting and replacement of the seal.

  3. Re-soldering the affected section with silver to ensure the durability of the repair.

  4. Nitrogen test at 300 psi for 30 minutes: no leaks detected.

  5. Complete vacuum draw of the system (500 microns).

  6. Accurate recharging of R-410A refrigerant according to Midea nameplate.

Results after intervention

After restarting, the measurements showed a clear improvement:

  • Blowing temperature: 10.8°C ;

  • Room temperature: 23.1°C ;

  • Differential: 12.3°C — in line with Midea factory performance;

  • The compressor has returned to smooth and quiet operation .

We also checked the defrost cycles and the evaporator sensor for proper operation. The customer noticed an instant coolness in the living room, confirming the system's return to full efficiency.

AirGreen Tips to Avoid Performance Loss

In order to prevent any recurrence, we recommended to the client:

  • Annual maintenance with complete cleaning of the coils and checking the tightness of the fittings;

  • Replacing the internal filters every three months ;

  • An inspection of the wiring and refrigerant insulation before each air conditioning season;

  • Adding a preventive leak test during periodic maintenance.

These simple measures extend system life and reduce energy consumption.

AirGreen: The trusted choice for your Midea systems

Thanks to our experience on Midea , Fujitsu , Sharp and Gree systems, we guarantee accurate diagnostics and certified repairs.
Our teams cover all of Greater Montreal , including Laval, Longueuil, the North Shore and the South Shore , and respond quickly to any HVAC emergency.

At AirGreen , each intervention is carried out according to the highest technical standards in order to restore the comfort, performance and reliability of your wall-mounted heat pump.