A broken wall-mounted heat pump in a charming Montreal duplex
One summer morning in Rosemont–La Petite-Patrie , our AirGreen team was called to work in a typical Montreal home, where natural wood sits alongside red brick. The owner informed us that his Gree wall-mounted heat pump —installed in the dining room, just above a large decorative mirror—was no longer blowing cold air.
The residence, bright thanks to its large windows, quickly let the heat of the sun in. Thermal comfort was compromised, and the client needed a quick and lasting repair before the next heat wave.
Fault diagnosis: a communication problem between the units
Upon arrival, we ran a series of tests on the Gree wall-mounted heat pump , an inverter- technology model powered by an R-32 compressor. The indoor unit appeared operational: the fan was running, but no heat exchange was taking place. Outside, the condensing unit remained silent.
Our technicians immediately suspected a communication error between the two units —a common problem on some models after several years of use. Using our specialized diagnostic tools, we confirmed that:
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the supply voltage (240 V) was stable,
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the protective fuses were intact,
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but the control signal was not transmitted from the indoor unit to the outdoor.
AirGreen intervention: replacement of the communication cable and recalibration
We removed the indoor unit cover and checked the wiring connecting the two units. The cable, slightly oxidized due to moisture accumulating near the wall pass-through, had lost its conductivity. This defect interrupted communication between the indoor unit and the outdoor power board.
Our technicians have:
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Replaced the communication cable with Gree-compliant shielded wire, resistant to interference and moisture.
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Cleaned the connectors and tightened the connection terminals.
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Reprogrammed the main board to restore synchronization between units.
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Checked the refrigeration circuit pressures (R-32) to ensure no leaks were present.
A few minutes after the power was turned back on, the Gree wall-mounted heat pump resumed its normal cycle. The indoor blowing temperature dropped quickly to 16.8°C , a sign of optimal heat exchange.
A unique environment, a necessary adaptation
The installation, carried out in a bright room with wooden walls, required special attention:
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the airflow had to be directed so as not to directly hit the work table located under the unit,
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and thermal sensing had to be recalibrated to account for ambient heat amplified by natural light.
We have adjusted the operating parameters (fan speed, automatic mode and shutter direction) to ensure even temperature distribution throughout the room, while optimizing energy consumption.
Maintenance recommendations for a Gree wall-mounted heat pump
As with all AirGreen services, we took the time to advise the client on preventive maintenance for their HVAC system. A well-maintained wall-mounted heat pump can last more than 12 years while maintaining consistent performance.
Here are the recommendations we made:
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Clean the internal filters every 4 to 6 weeks.
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Clear the exterior coils of any obstructions (leaves, dust, pollen).
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Have the refrigerant pressure checked every two years.
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Schedule a complete maintenance in the spring , before periods of intense heat.
We also installed a small voltage sensor to prevent any sudden surges or shutdowns—a common cause of electronic failures on inverter models.
AirGreen expertise in Montreal and the greater metropolitan area
The homes of Rosemont–La Petite-Patrie , often renovated while retaining their period charm, represent a challenge for modern heating and air conditioning systems. Thanks to our experience, we know how to adapt each installation to the unique configuration of Montreal buildings.
Our interventions are not limited to repairs: we analyze the entire thermal behavior of the home to offer optimized solutions, whether it is a Gree, Fujitsu, Midea, Sharp, Daikin wall-mounted air conditioner or a multi-zone heat pump .
A successful repair, comfort restored
At the end of our intervention, the client was able to notice an immediate return to the desired comfort. The heat pump operated silently, the interior temperature stabilized around 22°C , and the electricity consumption displayed on the monitoring module remained perfectly normal.
Before leaving, we noted the date of the next preventive maintenance and added this residence to our AirGreen monitoring program, guaranteeing peace of mind throughout the year .
AirGreen: your HVAC partner in Montreal, Laval, Longueuil and on both shores
At AirGreen, we are committed to providing fast, thorough and personalized HVAC repair services , adapted to the local realities of Montreal, Laval, the North Shore and the South Shore .
Each service call, like the one for this Gree wall-mounted heat pump in Rosemont , reflects our mission: to combine technology, expertise and human proximity to maintain the comfort of Quebec homes in all seasons.