Home » Some of Our Service Calls in Greater Montreal » Repair of a Fujitsu wall-mounted heat pump in Sainte-Thérèse
Réparation d’une thermopompe murale Fujitsu à Sainte-Thérèse
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Repair of a Fujitsu wall-mounted heat pump in Sainte-Thérèse

A broken compressor under the sun: rapid and efficient technical intervention

During a service call in Sainte-Thérèse , our AirGreen team was called in for a complete breakdown on a Fujitsu wall-mounted heat pump . The customer contacted us after noticing that their outdoor unit—located in a side driveway shared by several residences—was no longer starting despite repeated attempts to restart it. On a hot day, the situation required rapid intervention to avoid prolonged discomfort.

Initial inspection: a Fujitsu unit properly installed, but at a complete standstill

On site, our technician found the Fujitsu outdoor unit well maintained and installed on a stable wooden base, alongside other central systems belonging to the neighbors. However, there was no sign of activity:

  • No compressor vibration

  • Outdoor fan inactive

  • No electrical sound on startup

The customer had already checked the circuit breakers and cleaned the filters in the indoor unit, so the fault appeared to be in the outdoor unit itself.

Diagnosis: Internal electrical fault in the power module

Thanks to our specialized measuring instruments, we quickly identified the origin of the problem:
➡️ The power electronic board (inverter PCB) had a complete failure.

The readings showed:

  • Correct input voltage (240 V),

  • No output to the compressor,

  • No command sent to the fan.

These symptoms confirm a faulty control board , often caused by power surges or moisture entering the electronics box.

Intervention: replacement of the Fujitsu electronic card

Our regional warehouse had compatible cards for the Fujitsu ASU12RLF series , a model popular in Montreal and the North Shore. After validating the serial number, we proceeded to:

  1. Powering down and completely securing the system.

  2. Disassembly of the electronic box and removal of the defective card.

  3. Installing the new inverter board.

  4. Powering up and synchronizing the indoor/outdoor modules.

The whole thing was completed in just over an hour, including final testing and communication adjustments between the units.

Final checks: optimal performance and quiet operation

Once the system was rebooted, the results were immediate:

  • Fujitsu compressor : smooth and stable start-up.

  • Outdoor fan : speed modulated according to demand.

  • Discharge temperature : 10.8°C in cooling mode.

No error codes, no abnormal vibrations. The unit has resumed quiet and efficient operation, characteristic of high-efficiency Fujitsu models.

Advice given to the client: prevention is better than cure

Our technicians reminded the customer of a few simple steps to extend the life of their HVAC system :

  • Install a surge protector on the circuit dedicated to the heat pump.

  • Clean the outdoor coils every spring.

  • Check that the condensate drains properly.

  • Schedule a complete annual maintenance to prevent card failures caused by dust or humidity.

We also took the time to explain how to recognize the first signs of a faulty inverter board:

  • The indoor unit seems to be responding, but no cold air is coming out.

  • The compressor no longer starts.

  • The lights are flashing or displaying intermittent codes.

AirGreen: a recognized HVAC service on the North Shore and in Greater Montreal

At AirGreen , we specialize in Fujitsu wall-mounted systems , a brand renowned for its energy efficiency and reliability. Our technicians are trained and certified to work on all residential and multi-zone models , using genuine parts and diagnostic tools that meet manufacturer standards.

We quickly serve Montreal, Laval, the North Shore and the South Shore , and each service call is treated with the same rigor: precise diagnosis, lasting repair and professional service .

Result: restored comfort and optimized performance

Within minutes of restarting, the customer confirmed that he immediately felt the flow of cold air inside his home. His Fujitsu heat pump was back to its original performance and efficiency, ready to face the hot days ahead.

This intervention clearly illustrates the importance of calling on an authorized and experienced team , capable of quickly identifying the cause of a breakdown and correcting it without compromise.