Repair of a Fujitsu MultiZone heat pump in Côte-des-Neiges–Notre-Dame-de-Grâce

A high-rise heat pump, a precise diagnosis by AirGreen

In an apartment building in the Côte-des-Neiges–Notre-Dame-de-Grâce area of ​​Montreal , our AirGreen team was called to work on a Fujitsu MultiZone heat pump installed on a high balcony . The outdoor unit, well protected by a wooden fence, appeared to be in good condition at first glance—but an intermittent performance issue reported by the customer indicated that further diagnostic work was required.

The owner noticed that some areas of his condo were no longer cooling efficiently, despite the proper operation of other wall-mounted radiators connected to the same system. This was a typical case of imbalance between zones that needed to be resolved quickly, before the summer heat became unbearable.

Diagnosis: pressure imbalance in the MultiZone circuit

Upon our arrival, we carried out a complete inspection of the system:

• Checking the refrigerant circuit pressures : one of the circuits showed slight underpressure, suggesting a micro-leak.

• Visual inspection of the Fujitsu outdoor unit : no visible oil traces, but the evaporator surface showed excessive condensation on one side only .

• Analysis of the behavior of the interior heads : two zones responded normally, while the third showed a significant cooling delay and a 3°C higher blowing temperature.

Our technicians quickly identified a desynchronization of the electronic expansion module affecting one of the network branches. This type of problem is common on MultiZone systems when the refrigerant circulates unevenly.

AirGreen intervention: precision and technical rigor

Here’s how we went about restoring the heat pump’s full performance:

1. Deep cleaning of the outdoor condenser
   We removed the protective grille to expose the fins and eliminate the thin layer of dust that accumulated between the slats. Optimized airflow always ensures better heat transfer, especially on units installed high up like this one.

2. Checking and resynchronizing the electronic expansion module
   After unplugging the system, we reset the Fujitsu module and recalibrated the internal electronic valves via the maintenance control panel. This operation allows the zones to be rebalanced to optimal pressures and flow rates.

3. Adding R410A refrigerant
   A slight recharge was carried out in order to reach the values ​​recommended by the manufacturer, correcting the initial underpressure.

4. Full performance test
   Once the system was powered back up, we measured:

   • Blowing temperature at 10°C below ambient in all areas.

   • Stabilized and balanced pressures across all circuits.

   • Power consumption in accordance with factory values.

Results: uniform comfort and controlled consumption

After our intervention, the client immediately noticed:

• Even cooling in all rooms.

• A reduction in operating noise from the outdoor unit, often caused by pressure imbalance.

• Stabilization of electricity consumption , with optimized compressor performance.

By restoring the original operating parameters, the Fujitsu MultiZone heat pump regained almost new efficiency.

AirGreen Recommendations for High-Rise Installations

This type of installation on a balcony or enclosed terrace requires special attention:

• Ensure sufficient lateral ventilation : a minimum of 30 cm of space around the condenser is crucial.

• Avoid permanent visual obstacles (signs, closed fences) that restrict airflow.

• Carry out a complete annual maintenance , particularly before the summer season, to check the pressures and clean the exchangers.

• Monitor performance fluctuations between zones—often the first sign of a MultiZone circuit imbalance.

Conclusion: expertise and reliability at the heart of the AirGreen service

Thanks to our expertise in Fujitsu MultiZone systems , we were able to diagnose and correct a subtle fault before it compromised the comfort of the entire apartment.
This intervention in Côte-des-Neiges–Notre-Dame-de-Grâce perfectly illustrates AirGreen's rigor: a methodical approach, respectful of manufacturer standards, and a constant concern for energy efficiency.

Whether for repair , preventive maintenance or installation of HVAC systems in Montreal, Laval, Longueuil or on the North Shore and South Shore, AirGreen remains the trusted partner for lasting comfort, 12 months a year.

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