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

An HVAC service call on the South Shore for an exterior electrical problem

At AirGreen , we were recently called to Sainte-Julie , on the South Shore of Montreal, to diagnose a Gree wall-mounted heat pump whose outdoor unit was no longer starting. The customer had noticed that the fan was no longer starting and that no compressor noise was perceptible, despite a normal display on the indoor unit.

First inspection: finding the problem

Upon our arrival, our certified HVAC technicians performed a complete visual inspection of the installation . The outdoor unit, mounted on a galvanized support on the terrace, presented several signs:

  • Exposed and disorganized power wiring , possibly as a result of unprofessional intervention;

  • Electrical box poorly insulated against moisture;

  • Protective duct slightly detached, allowing condensation to enter the cable harness.

These observations indicated a high risk of short circuit or interruption of the control signal between the units.

Step 1: Detailed electrical diagnosis

We started by turning off the general power at the main circuit breaker before:

  1. Test the input voltage at the external disconnect box (240 V confirmed).

  2. Check the continuity of the communication cable between the indoor and outdoor terminals.

  3. Examine the Gree unit's electronic control board for signs of corrosion or burning.

The multimeter revealed a discontinuity in the signal cable , caused by a loose connection inside the wall box. This defect prevented the outdoor board from receiving the start signal from the indoor unit.

Step 2: Repair and reorder the wiring

Our team undertook a complete overhaul of the electrical connection:

  • Replacement of damaged quick connectors with secure compression terminals;

  • Reorganized the wiring harness with new heat shrink tubing and sealed conduit;

  • Reinstallation of the cut-off box according to CSA standards, with anti-condensation tilt and reinforced metal fixing.

A continuity and polarity test then confirmed that the signal was flowing correctly between the units.

Step 3: Restart and functional checks

Once the system was powered back up, the electronic board received the control signal , and the compressor started normally after a few seconds. The outdoor fan started smoothly, indicating that the problem was strictly electrical and not mechanical .

We then proceeded to:

  • A check of the R410A refrigerant pressure (normal values);

  • A compressor inrush current control;

  • A measurement of the indoor blown air temperature to confirm the cooling efficiency.

The readings obtained were in accordance with the Gree brand specifications.

Step 4: Securing and maintenance tips

To prevent any recurrence, we have implemented several preventive measures:

  • Application of dielectric gel in electrical connectors;

  • Sealing of chutes and wall inlets with HVAC silicone sealant;

  • Added additional plastic protection around the outer casing to prevent rainwater infiltration.

We also recommended that the client schedule an annual inspection of the heat pump's electrical circuit , especially when it is exposed outdoors on a wooden deck.

Final result: a fully functional heat pump

After restarting, the Gree heat pump worked perfectly:

  • Smooth start cycle , no communication errors;

  • Stable cold airflow inside;

  • No vibration or abnormal noise detected.

The relieved customer found optimal comfort while benefiting from an installation that is now secure and complies with HVAC electrical standards .

AirGreen expertise: reliability and technical precision

Each AirGreen intervention is based on a complete diagnosis and meticulous execution. Our technicians:

  • Comply with CSA and RBQ safety protocols ;

  • Use calibrated measuring tools (multimeter, current clamp, leak detector);

  • Guarantees a long-lasting repair thanks to certified components.

We operate in Sainte-Julie , but also throughout the South Shore, Laval, Montreal and the North Shore , for any problem related to your heating, ventilation and air conditioning (HVAC) systems.

At AirGreen , our mission is simple: restore performance, secure the installation and ensure the lasting comfort of our customers .