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Réparation d’une thermopompe murale LG à Sainte-Julie
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Repair of an LG wall-mounted heat pump in Sainte-Julie

A service call that reveals a performance problem

At AirGreen , our specialized HVAC repair team operates daily in the greater Montreal , Laval , and South Shore areas to restore appliances essential to daily comfort. Recently, we were called to Sainte-Julie , on the South Shore, to diagnose and repair an LG Smart Inverter wall-mounted heat pump that was showing signs of loss of efficiency.

The customer, a single-family brick home owner, contacted us after noticing that his outdoor unit seemed to be running continuously, but the air blown inside remained lukewarm, even in cooling mode. This symptom is common on inverter systems, but requires a methodical approach to identify the true cause.

Diagnosis: analyze before dismantling

Our certified technician first performed a complete visual inspection of the outdoor unit. The unit, mounted on wall brackets, showed a slight accumulation of dust on the heat exchanger and some traces of surface oxidation —nothing to worry about. However, one detail caught our attention: the condensate pipe appeared clogged , causing a slight backflow of water towards the bottom of the unit.

After turning off the power supply via the service switch, we carried out the following checks:

  • Refrigeration pressures : slightly lower than normal, possible sign of a microleak.

  • Discharge temperature : too high, indicating an intermittently overheating compressor.

  • Temperature sensor : erratic values ​​on the control board.

  • Noise when the fluid expands : jerky, indicating a partial lack of refrigerant.

These combined elements pointed us towards a lack of refrigerant caused by a slow leak at a flare fitting .

Intervention: Complete restoration of performance

To correct the situation, we proceeded step by step:

  1. Complete recovery of the remaining refrigerant in the system using a certified recovery station.

  2. Nitrogen leak test to pinpoint the leak — it came from a poorly crimped fitting on the suction line.

  3. Remanufactured and re-torqued the flare , followed by an extended pressure test of 250 psi for 30 minutes, confirming no leaks.

  4. 500 micron vacuum to dry the refrigeration circuit.

  5. Recharge with R410A refrigerant according to the exact specifications of the LG manufacturer.

  6. Power up and performance test on both modes: heating and air conditioning.

Once the heat pump was restarted, the measurements were perfect: stable pressure, correct evaporation temperature, and significantly cooler indoor airflow. The customer immediately noticed the difference.

Results: comfort restored and energy efficiency restored

After the repair, the LG Smart Inverter wall-mounted heat pump returned to its original performance. Power consumption decreased significantly, as the unit no longer had to operate continuously to reach the desired temperature.

We also cleaned the condenser and repositioned the drain line to prevent further water backup. The customer was advised on some good maintenance practices:

  • Clean the internal filters every month.

  • Visually check the clearance around the outdoor unit.

  • Schedule annual preventative maintenance before each peak season.

AirGreen expertise: precision and transparency above all

At AirGreen, every repair is carried out with rigor and traceability. Our technicians have the necessary equipment to:

  • Detect microleaks using calibrated electronic instruments.

  • Check the electronic components (cards, probes, inverter compressors).

  • Adjust pressures and calibrate electronic expansion valves , as on LG Smart Inverter models.

  • Optimize the lifespan of your HVAC system while reducing your energy costs.

This case perfectly illustrates our approach: never replace a part unnecessarily, but understand the root cause of the problem before acting.

Conclusion: A system ready for all seasons

The LG Smart Inverter heat pump repaired in Sainte-Julie is now operating at full efficiency, ready to ensure comfort and energy savings, whether in the middle of summer or the middle of a Quebec winter.

Thanks to the rapid and careful intervention of our AirGreen team , the customer benefits from a stable, quiet and efficient indoor climate — while significantly extending the lifespan of their equipment.

AirGreen — Experts in repair, installation and maintenance of HVAC systems in Montreal, Laval, Longueuil, on the North Shore and the South Shore.