Unexpected breakdown on a Fujitsu unit: rapid diagnosis and lasting repair by AirGreen
At AirGreen , we were recently called for an emergency intervention in Sainte-Thérèse , on the North Shore of Montreal , where a Fujitsu wall-mounted heat pump was showing signs of weakness at the start of the hot season. The outdoor unit, installed on a south-facing brick balcony, was no longer starting and the customer had noticed a total lack of cooling for several days.
Background and initial assessment
The affected model belonged to the Fujitsu Halcyon series , a range known for its reliability and quiet operation. However, devices in this series, especially when they are more than 7 years old, may have problems related to:
-
Tired starting capacitors ,
-
Electronic cards sensitive to humidity ,
-
And micro-leaks of R-410A refrigerant due to thermal expansion.
Upon arrival, our technician noticed that the outdoor fan remained stationary despite the cooling call. The indoor unit was operating normally, but no heat transfer was occurring—a typical sign of a compressor or power circuit failure .
Step 1: Electrical and safety check
First of all, we turned off the main power to perform a full continuity test.
Results :
-
Correct voltage at 240 V,
-
Fuses intact,
-
But no current draw to the compressor when restarting.
So we opened the control box to inspect the internal electrical components.
Step 2: Start Capacitor Diagnosis
The compressor's slightly bulging capacitor was a clear sign of thermal damage. This small metal cylinder is essential for providing the initial boost to the compressor and fan motor.
➡ Solution: Complete replacement of the capacitor with an original Fujitsu part, suitable for the capacity and nominal voltage of the unit.
After replacement, we tried again: the fan started spinning again immediately, but an internal crackling noise suggested an additional problem.
Step 3: Check the compressor and refrigerant
We plugged in our digital pressure gauges and measured the static pressure: 85 psi — well below the 110 to 120 psi expected at room temperature.
This result confirmed a refrigerant leak . Using an electronic detector, we located the leak point: a micro-crack on the flare connection of the liquid pipe .
➡ Repair carried out:
-
Bleeding the circuit,
-
Defective soldering of the connection,
-
Nitrogen leak test at 350 psi,
-
Complete vacuum draw (micron gauge at 400 µm),
-
Recharge with the exact amount of R-410A prescribed by Fujitsu.
Step 4: Calibration and Performance Testing
After restoring the refrigerant level, the unit returned to its original settings:
-
Working pressure: 120 psi (low) / 390 psi (high),
-
Indoor blowing temperature: 10.2°C,
-
Discharge temperature: 44°C,
-
Sound level: 21 dB.
Energy efficiency was fully restored, and the client immediately noticed a return to comfort in the home.
Step 5: Preventive Maintenance Tips
Before leaving, we explained to the owner some best practices to extend the life of his Fujitsu heat pump:
-
Clean the indoor unit filters every 3 to 4 weeks .
-
Keep the outdoor unit free of leaves, dust or snow .
-
Schedule an annual AirGreen inspection to check electrical load and connections.
We also applied an anti-corrosion treatment to the condenser fins, as the exposed brick balcony promotes the formation of oxidation through runoff.
A complete and transparent service, signed AirGreen
This intervention in Sainte-Thérèse perfectly illustrates our approach: rigorous diagnosis, precise repair and transparent communication .
We documented every step for the customer, including pressure readings, before/after photos, and serial numbers of the parts replaced.
The final result:
“The unit works better than when I bought it!” commented the customer, delighted to have efficient and quiet air conditioning again.
Why trust AirGreen for your Fujitsu repairs
-
Certified technicians trained directly on Fujitsu systems.
-
Fast service in Montreal, Laval, Longueuil, North Shore and South Shore.
-
Original parts and warranty on repairs carried out.
-
Complete checks : electrical, refrigeration and mechanical.
At AirGreen, we believe that a well-maintained heat pump is a lasting investment in the comfort and energy efficiency of your home.
AirGreen – HVAC expertise at your service throughout the North Shore and Greater Montreal.
➡ Reliable diagnosis. Guaranteed repair. Restored performance.