Precision work on a roof terrace
At AirGreen , we are often called upon to work in modern apartment buildings in the Côte-des-Neiges–Notre-Dame-de-Grâce (NDG) neighborhood, where many HVAC systems are located on rooftop terraces . This was precisely the case during this service call: a customer reported that their Fujitsu HFI wall-mounted heat pump was no longer producing heat, despite repeated attempts to restart it.
The outdoor unit, securely mounted on concrete blocks, was exposed to wind and temperature fluctuations. This type of installation, typical of urban buildings, provides excellent ventilation but requires regular maintenance to prevent the accumulation of dust, ice, or debris.
Diagnosis: the compressor goes into safety mode
Upon arrival, our technicians noticed that the Fujitsu compressor was no longer starting and that an H6 error code was flashing on the indoor unit. This code is often linked to a communication problem between the indoor and outdoor modules. After checking the electrical voltages and wiring continuity, we confirmed that the problem was caused by a faulty outdoor circuit board .
This type of failure is common on Fujitsu HFI units after several years of use, especially when exposed to sunlight and weather. Montreal's extreme temperature fluctuations can, over time, damage the control circuits.
Repair: Card replacement and complete recalibration
The intervention took place in three stages:
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Cut off the power supply and disassemble the external electronic box.
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Complete replacement of the control board with a genuine Fujitsu part.
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Recalibration of the communication module between the indoor and outdoor units, to ensure cycle synchronization.
Once the system was powered back up, the compressor restarted without delay. The heat pump resumed its heating mode , reaching a blower temperature of 42°C in less than five minutes—proof of optimal performance.
Preventive maintenance and advice for the owner
After every repair, we always take the time to inspect the entire system to prevent future problems. In this case, our technician:
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Cleaned the outdoor condenser to remove dust accumulated on the fins.
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Checked the R-410A refrigerant pressure .
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Checked the drainage of the condensate pipe to prevent any water from returning to the wall unit.
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Recommended biannual maintenance , especially before winter and before summer.
We also advised the customer to never turn off the heat pump's power during the cold season. The Fujitsu system automatically defrosts, and a power outage could compromise this function.
Result: restored comfort and peace of mind
Thanks to this intervention, the customer's Fujitsu heat pump has regained full capacity. Power consumption has returned to stable levels, and the unit operates quietly—a clear indicator of a balanced compressor.
This type of repair perfectly illustrates our philosophy at AirGreen : combining technical rigor, original parts and transparent service to maximize the lifespan of HVAC systems.
Why choose AirGreen for your Fujitsu heat pump repairs in Montreal
We specialize in the repair and maintenance of Fujitsu heat pumps , which are known for their reliability and high efficiency, but require precise maintenance. Our teams operate in Montreal, Laval, the North Shore, and the South Shore , with fast turnaround times and a clear diagnosis at each visit.
Our technicians have extensive expertise on all Fujitsu ranges — HFI, Halcyon, MultiZone — as well as other leading brands such as Gree, Sharp, Midea, Goodman, Hitachi and Bosch .
Technical details of the intervention
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Device type : Fujitsu HFI wall-mounted heat pump (R-410A)
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Problem : Defective external electronic card
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Solution : Complete replacement and recalibration
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Location : Côte-des-Neiges–Notre-Dame-de-Grâce, Montreal
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Result : Stable operation, heating restored
At AirGreen
We don't just repair: we optimize every HVAC system to deliver performance, durability, and comfort, summer and winter.