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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

Meticulous intervention on a flat roof: AirGreen at the service of high-rise HVAC systems

Rooftop wall-mounted heat pump installations are common in modern buildings on the South Shore. This type of configuration, often chosen to free up floor space and reduce noise, requires special expertise in maintenance and safety. Recently, our AirGreen team was called to Sainte-Julie to diagnose a Gree wall-mounted heat pump that was no longer responding to controls and producing neither heat nor air conditioning.

Context of the intervention

The client, the owner of a commercial duplex, had noticed that the indoor temperature had been fluctuating considerably for several days. Despite stable electrical power and a working remote control, the indoor unit remained inactive . Furthermore, no compressor noise was audible outside. The installation, consisting of two units side by side on a flat roof, had been exposed to typical Quebec weather conditions—alternating heat, rain, and fine dust—an environment often overlooked in seasonal maintenance.

Diagnosis: precision above all

Our certified technicians undertook a complete diagnosis upon arrival:

  1. Power supply check : The circuit breakers were functional, but slight oxidation was observed on the power connectors of the Gree unit.

  2. Inspection of the control module : after removing the cover, we detected a deposit of conductive dust on the electronic board, probably responsible for an intermittent short circuit.

  3. Compressor and fan test : Both components showed normal resistance, but no activation occurred when powered up—an indication of a faulty control board .

  4. Checking the refrigeration circuit pressures : the R410A gas was stable, eliminating any suspicion of a leak.

Repair: precision and safety on the roof

Working on a flat roof requires rigor and suitable equipment. Our technicians secured the area before undertaking the complete replacement of the electronic board and the deep cleaning of the electrical compartment .

The key steps:

  • Disconnection and replacement of the Gree control board with a certified original part.

  • Thorough cleaning with compressed air of the outdoor unit and condenser.

  • Tightening of electrical terminals to prevent voltage loss.

  • Checking the grounding , often overlooked but essential on roofs where moisture can create potential differences.

  • Complete system test after reassembly, including air conditioning mode and heating mode.

Once the repair was completed, the heat pump restarted without delay, with a stable and quiet compression cycle.

Result: restored performance and increased reliability

Thanks to this intervention, the Gree system has regained all its efficiency:

  • Smooth air conditioning cycle , without temperature fluctuations.

  • Instant start with every command.

  • Silent operation restored, proof of a healthy compressor.

We also added anti-vibration pads under the wooden supports to improve stability and reduce resonant noise on the roof membrane. This small adjustment contributes greatly to the durability of the installation.

AirGreen Tips for Rooftop Heat Pumps

A heat pump installed on a flat roof is exposed to more rigorous conditions than a traditional wall-mounted unit. To extend its lifespan:

  • Have the system inspected twice a year , especially after winter and before the hot season.

  • Avoid the accumulation of debris around the fan, especially leaves and sand.

  • Check electrical connections to prevent corrosion.

  • Install raised support blocks to prevent water from pooling under the unit.

These simple precautions ensure consistent performance, while reducing long-term repair costs.

AirGreen expertise: safety, rigor and sustainability

At AirGreen , every service call is treated with the same high standards, whether it's for a single-family home, a condo, or a commercial building. Our mission: to ensure the reliability and performance of HVAC systems throughout Montreal, Laval, Longueuil, the North Shore, and the South Shore .

By combining our technical know-how with a human and rigorous service, we guarantee our customers sustainable, safe interventions that comply with manufacturer standards .