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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

Heat pump failure on a flat roof in Montreal

In the heart of the Rosemont–La Petite-Patrie neighborhood, a client who owns a duplex called us after noticing that his Fujitsu wall-mounted heat pump installed on the roof was no longer producing cooling. The outdoor compressor seemed active, but the air inside remained lukewarm, making summer days uncomfortable.

At AirGreen , we understand that a heat pump installed on a flat roof is exposed to demanding conditions: intense heat in the summer, extreme cold in the winter, and debris buildup. These elements can quickly affect the system's performance if rigorous maintenance is not performed.

Initial diagnosis: loss of efficiency and pressure fluctuation

Upon our arrival, our technician secured access to the roof using his safety equipment, before carrying out a complete check of the Fujitsu AIRSTAGE system .
Initial pressure measurements revealed low pressure on the evaporator side and rapid fluctuations on the pressure gauge , a classic sign of a lack of R-410A refrigerant or a partial obstruction in the circuit .

After a careful visual inspection, we spotted traces of oil at the base of the compressor , indicating a slow leak. This situation explains why the customer had been observing increasingly low performance over the past few weeks.

Technical intervention: rigor and precision

Once the diagnosis was confirmed, we took the following steps:

  1. Complete cleaning of the outdoor condenser , clogged with dust and accumulated particles from the roof.

  2. Leak detection using an electronic detector and nitrogen test. The leak came from the flare fitting of the liquid line , which was slightly cracked.

  3. Replaced the fitting and completely tightened to Fujitsu torque standards.

  4. Complete vacuuming of the circuit for 45 minutes to eliminate all traces of humidity.

  5. Recharge the system to the exact pressure recommended by the manufacturer for this model.

  6. Operation test in cooling and heating mode to ensure inverter stability and correct defrost cycle.

The results were excellent:

  • Pressure stabilized at 120 PSI (low) and 400 PSI (high);

  • Indoor outlet air temperature at 8°C after 10 minutes of operation;

  • No abnormal noise or vibration detected.

Roof installation: specific features and precautions

HVAC systems installed on flat roofs , as is often the case in Montreal, present certain challenges:

  • direct exposure to sunlight, which increases the operating temperature;

  • increased risk of condensation and thermal expansion;

  • restricted access requiring specialized tools.

That's why our AirGreen technicians undergo advanced roof safety training and use reinforced anti-vibration mats to extend the life of the unit.
During this intervention, we also replaced the anti-vibration shims under the heat pump and checked that the condensates were draining properly.

Result: comfort restored and efficiency regained

As soon as the repair was completed, the customer immediately noticed the difference:

  • rapid cooling of the main room;

  • quieter operation of the outdoor unit;

  • significant reduction in temperature variations.

We concluded the visit with personalized maintenance recommendations :

  • cleaning the internal filter every month during the summer,

  • visual inspection of the condenser twice a year,

  • and annual refrigerant charge verification by an AirGreen certified technician.

AirGreen: your HVAC partner in Montreal and throughout the region

At AirGreen , we put our expertise in Fujitsu wall-mounted heat pumps at the service of residents of Montreal, Laval, Longueuil, the North Shore and the South Shore .
Our teams stand out for their meticulous approach and attention to detail, whether for a one-off repair , preventive maintenance or a complete installation .

Each intervention is documented with photos, performance measurements and advice tailored to the client's environment.
Our goal: to guarantee the lasting comfort and energy performance of each HVAC system installed or maintained by us.

In conclusion

This Fujitsu heat pump repair in Rosemont–La Petite-Patrie perfectly illustrates the rigor and precision of our work. Thanks to a rapid diagnosis and comprehensive intervention, we not only restored the customer's comfort, but also optimized the system's durability for many years to come.