A quick intervention for a wall-mounted air conditioner that was no longer cooling
At AirGreen , we are regularly called out for wall-mounted air conditioning breakdowns during the summer season. This was recently the case in a residence in Saint-Lambert , on the South Shore of Montreal , where a customer contacted us after noticing that their Daikin wall-mounted air conditioner was no longer producing cold air.
Initial diagnosis: a subtle but significant failure
Upon arrival, we performed a full diagnostic of the Daikin system , a typical 9,000 BTU wall-mounted unit installed on the upper floor of a staircase. The customer reported that the unit appeared to be working—the fan was running, no error codes were appearing—but the room temperature was not dropping despite a setpoint of 20°C.
Our technicians quickly checked several points:
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Refrigerant pressures outside,
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Condition of the indoor coil and condensate drain ,
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Discharge and return temperature ,
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Electronic control card .
The diagnosis revealed an abnormal drop in pressure , typical of a micro-leak of refrigerant .
System repair and upgrade
Once the leak is located using an electronic detector near the flare connection, we have:
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Recovered the remaining refrigerant in accordance with environmental standards (according to the regulations of the Régie du bâtiment du Québec ).
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Redid the flare joint and tightened the fittings .
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Performed a nitrogen leak test at 300 psi for 30 minutes.
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Pulled a full vacuum down to 500 microns to remove all moisture.
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Recharged the system with R-410A according to the quantity specified by the manufacturer Daikin.
Result: comfort restored and efficiency regained
As soon as I started it up again, the difference was immediate:
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Air blown at 9°C ,
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Stable pressure ,
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Optimal operating silence .
The client found constant comfort in the stairwell, a point often difficult to air-condition in multi-story houses.
AirGreen Preventive Tips
We advised the customer on a few simple measures to extend the life of their Daikin system:
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Clean the internal filters regularly (every 2 to 4 weeks in summer).
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Avoid running the unit in “Dry” mode continuously, which can accelerate ice formation if the outside temperature is low.
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Perform a complete annual check including refrigerant pressure and condensate drain.
These precautions not only help avoid costly breakdowns, but also ensure optimal energy efficiency .
AirGreen expertise at your service
Every service call is an opportunity for our technicians to demonstrate the rigor and competence that AirGreen is known for in Montreal, Laval, Longueuil, on the North Shore and the South Shore . We work on all major brands of HVAC systems, including Daikin, Gree, Fujitsu, Midea, Sharp and Mitsubishi , whether for repair, maintenance or installation.
Our commitment: to ensure your comfort at all times , with rapid, precise interventions that comply with RBQ and CCQ standards.
Is your wall-mounted air conditioner no longer cooling?
At AirGreen , we are ready to respond quickly to diagnose, repair and restore your comfort—wherever you are in Greater Montreal.