A customer worried about an air conditioner blowing lukewarm air
In Saint-Lambert , on Montreal's South Shore , a customer recently contacted us after noticing that their Gree wall-mounted air conditioner was no longer producing cold air. The unit, installed in the living room of a single-family home, appeared to be working properly: the light was on, the indoor fan was running, but the room temperature wasn't dropping. This is a classic situation our AirGreen technicians frequently encounter as periods of intense heat approach.
Inspection and diagnosis: an indoor heat exchanger clogged by dust and humidity
Upon our arrival, our technician performed a complete visual inspection of the wall-mounted unit. Upon removing the front cover, he immediately noticed that the heat exchanger (evaporator) was heavily clogged with dust and accumulated moisture. This insulating layer prevented the efficient passage of air, drastically reducing the system's efficiency.
The symptoms confirmed this diagnosis:
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Warm air coming out of the air conditioner, despite the compressor being active.
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Refrigerant gas pressure stable, but evaporation temperature abnormally high.
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No ice on the coils, ruling out a major leak.
The main problem therefore stemmed from neglected maintenance , a common situation in wall systems after several seasons of use without professional cleaning.
Steps for repairing and completely cleaning the wall-mounted air conditioner
To restore the performance of this Gree air conditioner , we carried out a multi-step intervention:
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Removal of the front panel and lower shroud , allowing full access to the evaporator.
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Protect the wall and floor with a waterproof film before applying the cleaning product.
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Thorough cleaning of the fins using a biodegradable disinfectant solution, specially designed for Gree wall units.
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Suction and gentle pressure rinsing to remove fine particles trapped between the slats.
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Cleaning the tangential fan , often neglected, but essential to ensure good air circulation.
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Checked the condensate drain , which had become partially clogged, causing slow water flow.
After reassembly, we restarted the unit and checked the outlet temperature: the airflow dropped from 26°C to 15°C in less than two minutes , confirming a return to normal performance.
Lessons learned: Why the annual review is essential
This case perfectly illustrates the importance of annual preventive maintenance . Even the best wall-mounted air conditioners, such as those from the Gree brand, see their efficiency drop by more than 30% when the internal exchanger is dirty.
At AirGreen , we remind our customers that:
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Filters should be cleaned monthly during the warm season.
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A complete professional cleaning of the coil and fan is recommended once a year .
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Regular maintenance extends the life of the appliance, reduces power consumption and prevents costly breakdowns.
We offer complete maintenance packages covering cleaning, refrigerant pressure testing, and electrical inspection — available in Montreal, Laval, Longueuil, the North Shore, and the South Shore .
An effective intervention by AirGreen
Thanks to a quick and careful repair, the Saint-Lambert customer's Gree wall-mounted air conditioner now works like new. Comfort has been restored, and indoor air quality has improved.
The customer also chose to sign up for our AirGreen maintenance program , guaranteeing annual visits and priority intervention in the event of a future breakdown.