When the remote control no longer responds: an often overlooked warning signal
A customer in Beaconsfield , on Montreal's West Shore, recently contacted us about a control issue with his Fujitsu wall-mounted heat pump . According to him, the unit was no longer responding properly to the remote control: the modes were changing randomly, the fan was stopping abruptly, and sometimes the unit simply refused to turn on.
This type of situation is more common than you might think. At AirGreen , we know that a simple control malfunction can hide electrical anomalies, faulty sensors, or a weakened control board . The goal: quickly identify the cause and restore system reliability.
Initial inspection: between infrared signal and electronic card
Upon our arrival, our technician began by performing a series of simple tests:
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Checking the infrared signal emitted by the remote control using a reception tester.
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Observed the LED indicator on the Fujitsu indoor unit, which was flashing irregularly.
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Manual start test via the emergency button integrated into the electronic card.
These steps confirmed that the problem was not with the remote control itself, but with the wall unit . The internal infrared sensor, located on the front of the panel, was no longer receiving signals correctly due to an intermittent short circuit in the control board.
Detailed diagnosis: faulty control board
This customer's Fujitsu heat pump was a ASU12 series unit, a model known for its energy performance, but some older units can develop weaknesses in the PCB after several years of intensive cycling.
When dismantling the front panel, our technician noticed:
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A buildup of fine dust and moisture around the card.
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Light oxidation on the IR sensor connector.
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A partially burnt relay , responsible for the fan stopping unexpectedly.
Using our measuring instruments, we confirmed that the board's power supply voltage was fluctuating abnormally between 4.8V and 5.5V, causing communication losses between the internal modules.
Intervention: card replacement and sensor calibration
To restore the reliability of the system, we carried out a series of specific technical interventions:
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Replacement of the PCB control board with an original Fujitsu model, fully compatible with the ASU12 series.
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Complete cleaning of the infrared sensor and reapplication of a dielectric insulator to prevent future moisture infiltration.
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Unit software reset : recalibrates the room temperature sensor and synchronizes heating/cooling modes.
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Checking the fan operating current and adjusting the airflow to ensure optimal acoustic comfort.
Once these steps were completed, the heat pump resumed normal operation: the remote control responded instantly, the airflow was stable, and the indoor temperature adjusted precisely.
Restored comfort and extended durability
This type of repair demonstrates the importance of regular maintenance of wall-mounted HVAC systems , especially in environments where dust and moisture can sneak in.
At AirGreen, we recommend that homeowners have their heat pump checked at least once a year , even if it appears to be working properly. This helps:
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Prevent electronic failures due to humidity.
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Optimize room temperature accuracy.
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Reduce energy consumption through stable operation.
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Extend the life of the Fujitsu system .
The Beaconsfield customer immediately noticed an improvement in comfort: rapid response to commands, constant airflow and restored operating silence.
AirGreen Expertise: rapid and certified intervention on the West Bank
Our technicians serve the entire West Shore of Montreal , including Beaconsfield, Pointe-Claire, Kirkland, and Dorval , with fully equipped mobile units. We repair and maintain all major HVAC brands— Fujitsu, Gree, Midea, Sharp, Haier, Goodman, Lennox, Bosch, and many more .
Each AirGreen intervention combines in-depth diagnosis, original parts and preventive advice , in order to ensure our customers lasting performance and comfort in all seasons.
In conclusion
This Fujitsu wall-mounted heat pump repair in Beaconsfield perfectly illustrates the AirGreen philosophy: precision, transparency, and technical expertise. A well-timed circuit board replacement can prevent major breakdowns and prolonged discomfort, while preserving your home's energy efficiency.