A breakdown in the heat: a precise and rapid diagnosis by AirGreen
One Friday morning in June, our AirGreen team was contacted by a family in Saint-Lambert , on the South Shore of Montreal , with an urgent problem: their Fujitsu wall-mounted air conditioner was no longer adequately cooling the house despite apparently working. The indoor temperature was over 27°C, and the airflow seemed barely warm, suggesting a performance issue with the HVAC system .
Our mission: to restore freshness and tranquility to the home in less than 24 hours.
Complete Inspection: Understand Before You Repair
Upon our arrival, we carried out a complete diagnosis of the Fujitsu air conditioner , a 12,000 BTU wall-mounted inverter model, typical of residential installations in Saint-Lambert.
Using our professional infrared thermometer , we recorded an air outlet temperature of 10.3°C , confirming a significant drop in performance (normal temperature should be between 6°C and 8°C in air conditioning mode).
Our technicians quickly identified several clues:
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Internal filters heavily clogged , reducing air flow.
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Partially frosted evaporator coil , indicating an imbalance in the refrigeration cycle.
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Refrigerant pressure below manufacturer's specifications , indicating a probable microleak.
Repair steps: rigor and technical precision
1. Disassembly and complete cleaning of the indoor unit
We started by removing the panels of the Fujitsu air conditioner to access the evaporator.
Using a biodegradable cleaning product and a gentle, low-pressure jet, we removed dust and deposits from the fins, while preserving the integrity of the sensors.
2. Checking the refrigeration circuit
We then connected our digital pressure gauges to measure the R-410A refrigerant pressure. The observed value, 20 psi lower than the standard, confirmed a minor leak at a flare fitting near the wall.
We have :
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tightened and re-tightened the connection ,
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resealed with a high-pressure copper gasket,
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then tested with nitrogen to ensure no loss.
3. Vacuuming and recharging the system
Once the circuit was secured, we performed a full vacuum for 30 minutes to remove all moisture and contaminants, then recharged the system to the exact charge prescribed by Fujitsu (0.98 kg of R-410A) .
4. Calibration and performance testing
After recharging, we restarted the system in maximum cooling mode.
Immediate result:
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Air outlet temperature at 6.7°C ,
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Balanced pressures,
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Stable and continuous compressor noise,
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No perceptible vibration.
Why the performance of a wall-mounted air conditioner depends on small details
Many homeowners are unaware that a simple microleak or neglected filter can reduce the performance of an HVAC system by more than 30% . In the case of this Fujitsu air conditioner , dust buildup on the evaporator was preventing proper heat transfer, while the microleak was creating a pressure imbalance that was unnecessarily straining the compressor.
At AirGreen , we always insist on prevention through regular maintenance : annual cleaning and pressure checks help prevent costly breakdowns and extend the life of the air conditioner.
Final result: restored comfort and regained efficiency
A few minutes after our intervention ended, the family immediately felt the difference:
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Indoor temperature dropped to 22°C,
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Barely audible sound level,
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Constant, pleasant cold air in every room.
The Fujitsu wall-mounted air conditioner is now operating at full capacity, ready to face the summer heatwaves typical of the South Shore .
What this case demonstrates about AirGreen expertise
Our interventions are based on three essential pillars:
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A methodical and measured diagnosis – each piece of data (pressure, temperature, intensity) is analyzed before any action.
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A lasting repair – no temporary solutions, only certified fixes that meet manufacturer standards.
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Transparent customer support – we always explain the cause of the problem and what to do to prevent future breakdowns.
It is this level of requirement that makes AirGreen a reference in HVAC system repair in Montreal, Laval, Longueuil, on the North Shore and the South Shore .
AirGreen Recommendations for a High-Performance Fujitsu Wall-Mounted Air Conditioner
To keep your device in perfect condition, here are our tips:
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Clean the filters every 4 to 6 weeks.
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Monitor the air outlet temperature using an infrared thermometer: if it exceeds 9°C, it's time to call a professional.
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Avoid high pressure cleaning which can damage the fins.
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Schedule an annual inspection to check the refrigerant charge and the proper operation of the inverter compressor.
Regular maintenance is not just about comfort: it also ensures optimal energy consumption and a longer lifespan.
Conclusion: AirGreen, your trusted HVAC partner in Saint-Lambert
This intervention once again demonstrates our commitment: to providing precise, fast, and lasting repairs to our residential customers in the greater Montreal area. Thanks to our expertise, this Fujitsu air conditioner is now as efficient as the day it was first installed.
Whether it's a performance issue , a refrigerant leak , or a complete diagnosis , trust AirGreen — your HVAC specialists for over a decade.