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Réparation d’un climatiseur mural Fujitsu à Saint-Bruno
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Fujitsu wall-mounted air conditioner repair in Saint-Bruno

A service call for a Fujitsu wall-mounted air conditioner that was no longer cooling

At AirGreen , we were recently contacted for a Fujitsu wall-mounted air conditioner repair in a residence in Saint-Bruno , on the South Shore of Montreal. The customer contacted us after noticing that their unit was no longer producing cold air, despite the normal display and the usual operating noise. The unit, installed in a bedroom, was located directly above a ceiling fan, a common configuration but sometimes a source of complex air circulation.

This Fujitsu model, from the Halcyon series , is a device known for its durability and quiet operation. However, like any HVAC system, it requires periodic maintenance and accurate diagnosis when a malfunction occurs.

Diagnosis: A faulty internal temperature sensor

During our visit, our technicians performed a complete inspection of the indoor unit. The unit's indicator lights indicated an internal communication error , often associated with a sensor failure. Upon opening the front panel, we found that the evaporator temperature sensor (thermistor) was sending an inconsistent reading to the control board.

This part plays a vital role: it measures the temperature of the blown air and adjusts the compressor speed. When it fails, the unit assumes the desired temperature has already been reached and stops cooling, leaving the customer with a simple blast of warm air.

Repair steps: precision and safety above all

Since space was limited by the ceiling fan, we first secured the work area. After turning off the power, we:

  1. Removed the front cover and disconnected the control module.

  2. Tested the thermal sensors with a digital multimeter to check the resistance at room temperature.

  3. Confirmed the failure of the evaporator probe , whose values ​​were well outside the normal range (10 kΩ at 25°C).

  4. Replaced the probe with a genuine Fujitsu part compatible with the Halcyon model.

  5. Cleaned the coils and filters to optimize airflow efficiency.

  6. Recalibrated the electronic board and tested the boot sequence.

As soon as I turned it back on, the difference was immediate: the unit started blowing air at 10°C in cooling mode, and the ambient room temperature dropped quickly to 22°C after just 15 minutes.

Optimizing Air Circulation with a Ceiling Fan

This intervention also addressed an often-overlooked aspect: the interaction between a ceiling fan and a wall-mounted air conditioner . In the case of our client in Saint-Bruno, the fan was facing upwards, creating an airflow that brought heat from the ceiling back to the air conditioner. This could distort the reading of the thermal sensor.

Our technicians advised the customer to:

  • Point the fan downward in summer to promote fresh air circulation.

  • Maintain a moderate speed so as not to disturb the air conditioner sensors.

  • Clean the filters and fan blades regularly to limit the dust drawn into the wall unit.

Thanks to these adjustments, the energy efficiency of the Fujitsu system was improved by almost 15%, according to our post-intervention measurements.

Result: restored comfort and optimized efficiency

After the repair, the customer was able to enjoy stable thermal comfort and quiet operation again. The Fujitsu system, once recalibrated, demonstrated its reliability:

  • Constant blowing temperature at 10°C.

  • Sound level less than 25 dB.

  • Smooth restart after power failure.

This intervention perfectly illustrates our approach at AirGreen : combining rigorous diagnosis , original parts and field experience to offer a sustainable and efficient service, whether in Montreal, Laval, Longueuil, on the North Shore or the South Shore.

AirGreen recommendations to prevent this type of breakdown

To prevent this type of problem from happening again, we advise our customers to:

  • Complete annual inspection before the hot season.

  • Professional cleaning of indoor and outdoor coils.

  • Checking thermal probes and electrical connections.

  • Proper temperature adjustment to avoid excessive stress on the compressor.

These simple actions extend the life of the system and ensure consistent performance, while reducing energy consumption.

AirGreen: your HVAC expert in Saint-Bruno and throughout the South Shore

With certified technicians and a comprehensive inventory of Fujitsu parts, AirGreen offers fast, professional service for any wall-mounted air conditioner or heat pump repair . Whether your unit is a Fujitsu, Sharp, Midea, Gree, Hitachi, or Daikin, our team has the skills and tools to quickly diagnose and repair any problem.

Our mission: to restore your comfort, optimize your energy consumption and ensure the sustainability of your residential HVAC systems.