A protected but failing heat pump: our AirGreen intervention on the South Shore
On Montreal's South Shore , Fujitsu Halcyon systems are among the most popular for their energy efficiency and reliability. However, even the best heat pumps require targeted maintenance and repairs after several seasons of use. Our AirGreen team was recently called to Saint-Lambert to inspect and repair a Fujitsu wall-mounted heat pump whose performance had gradually deteriorated.
Context of the service call
The client, owner of a single-family home, had noticed for several weeks:
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a reduction in heating in winter mode ,
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an unusual noise from the external compressor ,
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and unscheduled system shutdowns , especially on cold days.
The outdoor unit, installed under a balcony to protect it from snow, appeared intact at first glance. But this type of installation, while practical, can also retain moisture and limit air circulation , two factors that directly affect compressor performance.
AirGreen Diagnosis: A Pressure and Sensor Problem
Our technicians began with a complete check of the refrigeration cycle . The analysis revealed:
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Slightly lower than normal refrigerant pressure , indicating a slow microleak .
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A faulty suction temperature sensor , falsifying the control module readings.
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Slight oxidation on the compressor's electrical connectors.
These combined elements caused premature safety shutdowns: the electronic board believed that the compressor was overheating when it was simply operating with poor feedback.
Repair Steps
Our technicians proceeded methodically:
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Nitrogen flushing of the circuit to check for leaks.
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Replacement of the defective sensor with an original Fujitsu part.
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Restore R-410A refrigerant charge to exact manufacturer specifications.
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Cleaning the connectors and applying a protective coating against moisture.
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Performance test in heating and air conditioning mode , under pressure control and using an infrared thermometer.
Result: the system restarted smoothly, with stable and quiet performance . Blower temperatures returned to their optimal level, and power consumption fell by almost 20%.
A classic case: slow microleaks in wall-mounted heat pumps
This type of incident is common in residential HVAC systems . Microleaks—often invisible to the naked eye—can come from:
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compressor vibrations,
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joints slightly loose,
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repeated thermal variations.
At AirGreen, we use highly sensitive electronic leak detectors to intervene before a complete breakdown occurs. A slow leak can take more than a year to cause a loss of performance, but if left undetected, it often leads to premature compressor wear.
Best practices recommended by AirGreen
For owners of Fujitsu and other brand heat pumps, here are some simple tips:
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Clean the internal filters every two months.
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Clear the outdoor unit of any obstructions (plants, snow, leaves).
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Schedule an annual inspection with a certified technician.
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Adequately protect the unit , but without blocking natural ventilation.
These simple actions extend the life of the system and maintain optimal performance throughout the year.
AirGreen expertise on the South Shore
From Brossard to Sainte-Julie , via Saint-Lambert , our teams intervene daily for the maintenance, repair and installation of HVAC systems:
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Wall-mounted and central heat pumps ,
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Wall-mounted air conditioners ,
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Air exchangers and ducted systems ,
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PTAC and ceiling consoles .
Every AirGreen intervention is based on three principles: transparency, rigor, and sustainability . We never make unnecessary replacements—every part changed is justified and explained to the customer, with supporting photos.
Final result: comfort restored, efficiency restored
After our intervention in Saint-Lambert, the Fujitsu heat pump returned to optimal operation. The compressor noise disappeared, interior comfort was immediately noticeable, and the customer was able to notice a significant reduction in his energy bill .
At AirGreen, we don't just repair: we bring your HVAC systems back to life so they work like new, throughout Greater Montreal — Montreal, Laval, Longueuil, the North Shore and the South Shore .