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Réparation d’une thermopompe murale Fujitsu à Rosemont–La Petite-Patrie
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Repair of a Fujitsu wall-mounted heat pump in Rosemont–La Petite-Patrie

When a silent failure hides a control board problem

At AirGreen , we are often called upon to work on Fujitsu wall-mounted heat pumps , which are known for their reliability, but which can develop electronic problems with the control board over time. This is precisely what happened in a residence in the Rosemont–La Petite-Patrie district of Montreal , where the customer had noticed for several days that his unit was no longer responding to the remote control.

On-site diagnosis: a device that turns on, but does not start

Upon our arrival, our technician carried out a complete inspection of the Fujitsu wall-mounted heat pump , installed near a living room window.
The symptoms observed were as follows:

  • Steady indicator light , without starting the interior fan;

  • No reaction to the infrared remote control ;

  • Complete silence from the outdoor compressor , a sign that communication between the two units was interrupted.

Using a multimeter and a Fujitsu code reader, we quickly identified the problem: a faulty main circuit board , causing a loss of signal between the control module and the fan relay.

Technical intervention: targeted repair and restart

The replacement of the interior control board was carried out on site. We have:

  1. Cut off the main power supply to ensure safe intervention;

  2. Removed the front panel and filters to access the card;

  3. Carefully disconnected the communication cables between the board and the temperature sensor;

  4. Installed an original Fujitsu card compatible with the ASU series model;

  5. Performed a full system reset before powering back on.

After a few seconds, the fan restarted, and the heat pump began to distribute steady warm air—proof that communication between the units was reestablished.

Additional maintenance and recommendations

Taking advantage of the intervention, we carried out a thorough cleaning of the filters and the internal turbine , often clogged with fine dust.
We also have:

  • Checked the pressure of the R410A refrigerant , stable and in accordance with the service values;

  • Inspected the condensate drain pipe , slightly obstructed;

  • Cleaned the room temperature sensor , which had a slight deposit of dust.

All of this has improved airflow and ensured optimal energy performance.

Result: comfort restored and reliability restored

In less than two hours, the system was back up and running. The salon temperature stabilized at 21°C , and the customer was able to enjoy consistent comfort without any unwanted restarts.
We advised him to schedule a full annual maintenance before each winter to avoid dust buildup and electrical surges that often damage electronic boards.

Why choose AirGreen for your wall-mounted heat pump repairs?

Our RBQ and CCQ certified technicians work on all major brands: Fujitsu, Sharp, Midea, Gree, Bosch, Lennox, Goodman , and more.
With AirGreen , you benefit from:

  • A precise and rapid diagnosis , supported by specialized instruments;

  • Guaranteed original parts and transparent service;

  • With recognized expertise in Montreal, Laval, Longueuil, on the North Shore and the South Shore ;

  • From complete assistance , from troubleshooting to preventive maintenance.

AirGreen: Your Trusted Partner in Residential HVAC

Every day, we help families regain comfort in their homes through effective and sustainable interventions.
A well-maintained Fujitsu heat pump can last more than 15 years , provided it is regularly serviced and its electronic components are checked annually.

AirGreen – Heat Pumps, Air Conditioning & Heating in Montreal, Laval, Longueuil, North Shore and South Shore.