Loss of performance detected on a residential roof in Outremont
At AirGreen , we were recently commissioned for a service call in Outremont , in the historic heart of Montreal, where a customer reported a decrease in efficiency of their Fujitsu MultiZone heat pump installed on the roof of their building. The outdoor unit, exposed to climatic variations, was showing signs of fatigue: loss of power in heating mode, short cycles, and abnormal operating noise.
This type of situation is common for urban rooftop installations, where exposure conditions (wind, dust, thermal variations) accentuate the wear of the components. Our team intervened quickly to carry out a complete diagnosis and a lasting restoration .
Initial diagnosis: abnormal pressure and irregular temperature
Upon arrival, we visually inspected the Fujitsu Hyokan unit, which was mounted on anti-vibration mounts. No structural damage was visible, but several indicators suggested a refrigerant circulation problem .
When connecting our digital pressure gauges , we observed a lower than normal suction pressure , accompanied by an unstable discharge temperature. This possibly indicated a microleak in the refrigeration circuit or a partial restriction of the electronic expansion valve .
Step 1: Check the refrigeration connections
The MultiZone unit supplied three indoor wallheads. Upon inspecting the flare fittings, we discovered an oily trace at the main service port , indicating a slow leak of R-410A refrigerant . This type of leak can go undetected for several months while gradually degrading the system's performance.
Our technicians have:
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Isolated the faulty section of the circuit .
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Degassed the system by recovering the existing refrigerant.
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Cleaned and tightened the affected fitting .
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Replaced the gaskets before performing a full vacuum .
After these steps, a nitrogen leak test confirmed the perfect integrity of the circuit.
Step 2: System Reload and Calibration
We then recharged the Fujitsu heat pump with the exact quantity of R-410A prescribed by the manufacturer, respecting the length and the difference in level of the refrigeration circuit specific to this rooftop installation.
Once the charge was completed, we measured the discharge and suction temperatures: the values were now stable, and the hot air flow rate at the outlet of the indoor unit reached 45°C , proof of the return to optimal performance .
Step 3: Checking the electrical circuits and drainage
A complete electrical check was then carried out:
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Start capacitor : within nominal values.
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Main electronic board : no trace of oxidation or short circuit.
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Power wiring : compliant tightening and insulation.
We also cleaned the condensation drain , often forgotten, but essential to prevent water backups and ice formation on the roof during the winter.
Step 4: Preventive cleaning and air circulation optimization
Taking advantage of our presence on site, we carried out a complete cleaning of the condenser fins , which were clogged with dust and urban debris. Restricted air circulation can cause the compressor to overheat and reduce the system's lifespan.
To maximize energy performance, we also repositioned the refrigerant pipes to reduce stress on the hoses, a technical detail that contributes to better system durability.
Result: restored performance and satisfied customer
After restarting, the Fujitsu MultiZone heat pump demonstrated perfect operation:
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Stable temperature in all interior areas.
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Reduced noise level.
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Power consumption in accordance with original specifications.
The client, who used this system for a renovated residential triplex , was able to observe an immediate improvement in thermal comfort , particularly on the top floor where temperature fluctuations were previously significant.
AirGreen expertise for MultiZone systems in urban environments
Rooftop installations like the one in Outremont require rigorous maintenance and specific expertise. At AirGreen, we combine advanced diagnostic technology with in-depth brand knowledge to ensure the reliability of systems from Fujitsu, Gree, Midea, Sharp, and many others.
Our interventions always include:
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A complete analysis of the refrigeration circuit .
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Precise calibration of electronic parameters .
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Preventive cleaning to extend the life of the compressor.
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Personalized advice on seasonal maintenance to plan.
AirGreen Tips for Building Owners in Montreal
For building owners with MultiZone systems, here are some practical recommendations:
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Visually inspect your outdoor units twice a year .
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Schedule a professional maintenance before each extreme season (summer/winter).
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Make sure the refrigeration ducts are well insulated and secured .
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Clean the internal filters regularly to prevent pressure loss.
These simple actions extend the life of the system and prevent costly breakdowns.
AirGreen: your HVAC reference in Montreal, Laval, North Shore and South Shore
With a team of certified and passionate experts, AirGreen offers a complete repair, maintenance and installation service for residential and commercial HVAC systems . Whether for a wall-mounted, multi-zone or central heat pump , we operate with precision, transparency and professionalism throughout the greater metropolitan area.
Every intervention is an opportunity to restore comfort, performance and peace of mind to our customers.