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Réparation d’une thermopompe murale Fujitsu à Saint-Lambert
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Repair of a Fujitsu wall-mounted heat pump in Saint-Lambert

A service call in a confined space

At AirGreen , we are often called upon to intervene in residential contexts where the installation of an HVAC unit is constrained by space. This was the case during this repair of a Fujitsu wall-mounted heat pump in an apartment in Saint-Lambert , on the South Shore of Montreal. The client had noticed that his system, although recent, was no longer producing enough cold air, and that a dull noise was emanating from the outdoor unit located on his small balcony.

Initial inspection and problem assessment

Upon arrival, we noticed that the Fujitsu outdoor unit was installed in a narrow corner, partially surrounded by walls, which significantly reduced airflow around the condenser. On top of the unit, a forgotten tool—a small wire brush—suggested an attempt at DIY maintenance.

The customer told us that the system had worked well until the end of the previous summer, but at the start of the new season, the compressor was having difficulty starting and shutting down after a few minutes. Inside, the blown air remained lukewarm despite the cooling request.

Detailed diagnosis of the heat pump

Our AirGreen technicians carried out a complete analysis of the system:

  1. Electrical check : the compressor was receiving the nominal voltage, but a slight delay in starting indicated a problem with the start capacitor .

  2. Measurement of refrigeration pressures : a significant imbalance between high and low pressure suggested a backflow of hot air , caused by lack of ventilation.

  3. Airflow control : The confined space retained heat, forcing the compressor into thermal safety.

  4. Visual inspection : no apparent refrigerant leaks, but slightly bent lines, which restricted the flow of refrigerant.

Repair and optimization of the installation

Our team first replaced the start capacitor , a key component to properly restart the Fujitsu compressor. Then, to correct the ventilation problem, we:

  • Partially clear the space around the outdoor unit , by moving the pots and stored objects;

  • Installed an air deflector to channel the exhaust flow to the outside;

  • Cleaned the coils with a mild solution to improve heat exchange;

  • Checked and straightened the refrigeration lines to ensure optimal passage of R-410A gas.

After these adjustments, the heat pump resumed stable and quiet operation , with supply air temperatures meeting Fujitsu specifications.

Lessons Learned and AirGreen Recommendations

This type of situation highlights the importance of respecting the minimum clearances recommended by manufacturers. A heat pump, even a high-performance one, can see its efficiency drop by 30% if the hot air cannot dissipate properly. At AirGreen, we emphasize several key points to avoid these inconveniences:

  • Annual maintenance : cleaning and checking the refrigerant charge are essential before each hot season.

  • Respect clearances : leave at least 30 cm on each side of the unit for adequate airflow.

  • Installation in a well-ventilated area : avoid closed corners, enclosed balconies or spaces under stairs.

  • Use of an HVAC sun shield to limit overheating of the south-facing compressor.

A successful intervention in Saint-Lambert

At the end of the intervention, our technician was able to confirm optimal cooling performance , stabilized electricity consumption , and above all, restored interior comfort for the customer. The latter also appreciated our advice on the arrangement of elements around his balcony so as to no longer hinder the machine's breathing.

Thanks to our expertise and attention to detail, this Fujitsu wall-mounted heat pump now performs like new—proof that proper diagnosis and maintenance significantly extend the life of an HVAC system.