A service call reveals a complex electronic problem
At AirGreen , we were recently called to diagnose a problem with a Fujitsu central heat pump installed in a single-family home in the Sainte-Dorothée neighborhood of Laval . The customer had noticed for several days that the system was no longer starting properly: no indoor ventilation, but a slight noise from the outdoor unit. These signs indicated a possible problem with the control module or an electronic component of the condenser.
Step One: Circuit Inspection and Verification
Upon arrival, we undertook a complete inspection of the outdoor unit . The control panel cover was removed to access the internal components. Using our measuring instruments, including a dual-gauge digital manifold and a professional multimeter , we were able to confirm:
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A stable power supply arriving at the unit's circuit breaker.
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An intermittent control signal from the main module.
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A partially faulty control board , likely damaged by a power surge.
The circuit board showed signs of slight overheating and abnormal resistance on one of the compressor's power supply circuits. This type of failure is quite common on Fujitsu systems when voltage fluctuations are frequent—especially during the off-season, when compressors frequently cycle on and off.
Diagnosis confirmed: electronic card to be replaced
After isolating each component—relay, capacitor, and sensors—we confirmed that the main control module (PCB) needed to be replaced. An order was immediately placed with our authorized supplier Fujitsu. While awaiting receipt of the part, we performed:
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A complete cleaning of the connectors .
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A tightening of all electrical terminals .
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A check of the R-410A refrigerant charge to ensure that no leaks were the cause.
Final intervention and complete system test
Two days later, once the new electronic card was installed , we carried out a complete restart of the system . The test included:
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Soft start of compressor and fan .
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Reading high and low pressures using our gauges.
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Control of the blowing temperature inside the house.
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Measuring the operating current to ensure that the values remained within Fujitsu tolerances.
Result: The heat pump returned to normal operation, with optimal efficiency and restored thermal stability inside. The customer immediately noticed improved comfort and reduced outdoor noise.
The key points of this repair
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Initial problem: Complete system shutdown due to a faulty control board.
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Make and type: Fujitsu central heat pump, inverter compressor system.
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Location of intervention: Sainte-Dorothée district, Laval .
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Total service duration: 2 visits (diagnosis + final repair).
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Result: successful replacement of the electronic module, stable operation and efficiency restored.
AirGreen Preventive Recommendations
To avoid this type of breakdown, we advise our customers to:
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Have an annual electrical inspection of their HVAC system performed.
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Install a line surge protector to protect sensitive electronic boards.
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Clean outdoor units regularly to ensure good ventilation.
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Check the condition of drains and electrical connections at each change of season.
At AirGreen, we always prioritize prevention and transparency : our approach aims to extend the lifespan of HVAC systems while optimizing their energy performance.
Local expertise and fast service in Laval and surrounding areas
Our certified technicians work weekly in Laval , Montreal , Longueuil , the North Shore and the South Shore for all repairs on Fujitsu, Gree, Sharp, Midea, Bosch heat pumps, and more . Thanks to our local warehouse, we have a large number of original parts to guarantee fast and lasting repairs.
For any emergency or complex diagnosis, AirGreen remains your HVAC reference in Laval and the greater Montreal area .