A sudden breakdown at the start of summer
At AirGreen , we know how frustrating it is to see your wall-mounted heat pump stop working during the first warm days of the season. This is exactly the situation experienced by a homeowner in Sainte-Thérèse , on the North Shore of Montreal , when his Fujitsu Halcyon Inverter wall-mounted heat pump suddenly stopped. The outdoor unit, installed on a metal bracket along a brick wall, remained completely silent, with no sign of activity.
Rapid and rigorous diagnosis
Upon arrival, our technician began with a complete visual inspection . No signs of oil leaks or physical damage were apparent. However, the outdoor circuit board was no longer receiving a start signal from the indoor unit.
After checking the power supply and fuses, we used our diagnostic instruments to test communication between the two units—a critical protocol on inverter systems like the Fujitsu Halcyon series.
Result: a defective communication card
The problem stemmed from a damaged internal communication board , responsible for synchronization between the indoor module and the compressor. This failure, often linked to a power surge or micro-infiltration of humidity, prevented the compressor from starting and blocked the system in safety mode.
Repair steps performed by AirGreen
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Safely disconnect the HVAC system before any intervention.
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Open the control box and remove the faulty card.
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Installation of a new original Fujitsu card , perfectly calibrated for the Halcyon model.
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Checking the communication wiring and cleaning the connectors to remove any traces of oxidation.
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Gradual restart of the system and observation of operating cycles.
Once the replacement was completed, the unit resumed its normal cycles: the compressor started smoothly and the room temperature began to drop steadily. The customer was able to see a complete return to thermal comfort in his home in less than an hour.
A repair that highlights the reliability of the Fujitsu system
Fujitsu Halcyon wall-mounted heat pumps are renowned for their performance and durability. However, like any complex electronic device, they can experience isolated failures, often related to electrical surges or dust accumulation on sensitive components.
Thanks to our expertise, we were able to avoid a complete replacement of the compressor , which would have been much more expensive. This type of intervention illustrates the importance of an accurate diagnosis and qualified technicians , capable of identifying the real cause of a breakdown.
AirGreen Prevention and Advice
To reduce the risk of similar failures, we recommend our customers:
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To install a surge protector for outdoor units;
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Have the electronic card inspected at each annual maintenance;
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Keep ducts clean and clear , especially during seasonal transitions;
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And schedule a complete preventative cleaning including the coil, condensate drain and filters.
At AirGreen, our approach goes beyond simple repair: we aim for the long-term preservation of each HVAC system, to ensure consistent comfort and maximum energy efficiency.
End result: restored comfort and peace of mind
Thanks to our rapid intervention, the Fujitsu Halcyon wall-mounted heat pump in Sainte-Thérèse is now operating smoothly and quietly again. The customer enjoys cool, stable air, without interruptions or temperature fluctuations.
He also opted for our AirGreen annual maintenance plan , ensuring continuous monitoring of his equipment and prevention of future breakdowns.
AirGreen — Specialists in repair and maintenance of Fujitsu wall-mounted heat pumps in Sainte-Thérèse, Montreal, Laval, Longueuil, North Shore and South Shore.