A device that blows warm air: our expertise at the service of comfort
At AirGreen , we work every day in Montreal neighborhoods to resolve performance issues with residential HVAC systems . This service call, in Rosemont–La Petite-Patrie , involved a Fujitsu wall-mounted heat pump that was no longer cooling adequately, even after several restart attempts.
Symptoms reported by the client
The customer explained to us that for several days, the heat pump had been working without any apparent error, but the expelled air remained lukewarm despite a set point of 21°C.
When we arrived, the ambient temperature in the room reached 25.5°C, even though the unit seemed to be in air conditioning mode.
We immediately took a temperature reading at the blower using an infrared thermometer , which indicated 13.9 °C . This figure is higher than the norm for a well-calibrated Fujitsu unit, where the outlet temperature should fluctuate between 6 and 9 °C. The diagnosis was obvious: the heat pump was lacking in cooling performance .
Step 1: Inspect the indoor unit
The first step was to check the evaporator filters and coils .
The filters were moderately dirty, which can reduce airflow and limit heat transfer. We cleaned them thoroughly , as well as the heat exchanger fins.
After restarting, we took another measurement: 12.8°C . The improvement was minimal, which confirmed that the problem was elsewhere .
Step 2: Checking the refrigeration circuit
We then shifted our attention to the outdoor unit.
The pressure switches revealed abnormal low pressure on the suction side, while the high pressure remained stable. These inconsistent values suggested a slight refrigerant leak (R410A) , slow enough not to cause an immediate failure, but sufficient to reduce overall efficiency.
Using an electronic leak detector , we identified a micro-leak at a flare fitting . This type of problem often occurs as a result of repeated vibrations on copper piping.
Step 3: Repair and Reload the System
Our technicians carried out:
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Tightening the flare fitting and replacing the gasket.
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Tested under nitrogen at 300 psi to validate the seal.
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Complete vacuum draw for 45 minutes.
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Recharge R410A refrigerant to the nominal charge specified by Fujitsu.
After restarting the system, the supply air temperature quickly dropped to 6.7°C , indicating perfect performance. The difference of approximately 18°C between the inlet and outlet air confirmed that the heat pump was returning to its original efficiency.
Step 4: Calibration and additional checks
To ensure sustainable performance, we have:
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Checked the evaporator temperature sensor is working properly.
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Checked the indoor fan motor , sometimes subject to slowdowns.
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Cleaned the condensate and drain to prevent future overflow.
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Tested the different operating modes (heating, ventilation, dehumidification) .
All components responded correctly after the intervention.
Result: restored comfort and reduced consumption
The customer immediately noticed a clear difference: rapid cooling, quiet operation, and temperature stability .
Thanks to the precise refrigerant recharge and the realignment of the connections, the Fujitsu heat pump has regained its optimal performance , while reducing its energy consumption .
We also reminded the customer that annual preventative maintenance can help avoid this type of performance loss. A simple undetected leak can lead to compressor overload and premature system wear in the long run.
AirGreen expertise at your service
Our technicians specialize in HVAC repair and maintenance and work on all major brands of wall-mounted heat pumps : Fujitsu, Midea, Sharp, Gree, Trane, Mitsubishi, Zephyr, and more.
Whether you are in Montreal, Laval, Longueuil, on the North Shore or the South Shore , we offer:
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Accurate diagnostics using professional measuring tools.
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Fast and durable repairs according to manufacturer standards.
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Personalized advice to maximize the longevity and efficiency of your appliances.
In summary
This intervention in Rosemont–La Petite-Patrie demonstrates the importance of a rigorous diagnosis when the heat pump no longer delivers the correct temperature.
Thanks to our methodical approach—inspection, pressure testing, repair, and calibration—we were able to restore the fireplace's comfort and performance in a single visit .