Repair of a Fujitsu wall-mounted heat pump in Côte-des-Neiges

Precision diagnosis thanks to infrared technology

At AirGreen , every service call is handled with rigor, method, and expertise. On this day, our team visited an apartment in Montreal's Côte-des-Neiges neighborhood to repair a Fujitsu wall-mounted heat pump that was no longer providing enough hot air, despite normal operating noise.
The customer reported to us that the ambient temperature did not exceed 18°C , even after several hours of use.

Equipped with our thermal measuring tools, we quickly undertook a diagnosis using an infrared thermometer , an effective method for detecting performance anomalies without unnecessary disassembly.

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Diagnosis: low temperature difference between suction and blowing

From the first measurements, the anomaly was confirmed: the blowing temperature at the outlet of the wall unit was only 21.2°C , while the ambient temperature measured at the air return was 18°C.
A difference of only 3°C is well below the expected performance for a heat pump in good condition, which should show a difference of at least 8 to 12°C in heating mode.

Our initial observations revealed:

• Air filters clogged with fine dust;

• Slightly dirty internal exchanger ;

• Tangential fan slowed down ;

• No frost on the outer coil , which ruled out a defrosting problem;

• No error code on the indicator light.

These clues pointed to a loss of airflow efficiency and a possible imbalance in the refrigeration circuit .

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Steps for a thorough inspection

Our technicians followed a comprehensive verification procedure to isolate the exact cause of the problem:

1. Power off and remove the front cover.

2. Complete cleaning of filters with a biodegradable antibacterial solution.

3. Inspection of the interior temperature sensor (thermistor).

4. Blower motor check - minor fouling at shaft.

5. Measurement of pressures on the refrigeration circuit via the service valves of the outdoor unit.

Pressures were slightly lower than normal, indicating a partial loss of refrigerant (R410A).
This leak, probably due to a micro-crack on the flare connection , explained the reduced efficiency without generating a safety shutdown.

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Repair: cleaning, tightening and recharging the circuit

To restore system performance, our technicians carried out several key interventions:

• Disassembly of the lower panel to access the copper fittings.

• Tightening the flare fitting after applying a torque calibrated with a dynamometer.

• Nitrogen leak test at 300 psi — result: stable after 15 minutes.

• Recharge with R410A refrigerant according to Fujitsu manufacturer's specifications.

• Complete cleaning of the evaporator with dry steam and gentle brushing of the fins.

• Lubrication of the tangential fan shaft.

Once the assembly was reassembled, the heat pump was restarted for thermal validation.

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Results after intervention: optimal performance restored

New infrared thermometer measurements immediately confirmed the success of the intervention:

• Blowing temperature: 32.1°C

• Return temperature: 19.5°C

• Difference: 12.6°C , which is perfect for mid-season heating.

The customer immediately noticed a significant improvement in ambient comfort , with a rapid rise in temperature and a powerful and stable airflow.

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Personalized maintenance advice given to the customer

To prevent this type of drop in performance from happening again, our technician reminded us of some good practices:

• Clean filters every 4 to 6 weeks , especially in urban apartments prone to dust.

• Keep the outdoor unit clear of obstructions , especially during winter.

• Have the circuit pressures checked every two years by an approved professional.

• Monitor discharge temperature variations using a handheld infrared thermometer—an excellent indicator of system health.

These simple tips will help extend the life of your appliance while maintaining optimal energy efficiency.

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AirGreen expertise in Côte-des-Neiges and throughout Montreal

This intervention demonstrates AirGreen's expertise in repairing Fujitsu wall-mounted heat pumps and other well-known brands such as Midea, Gree, Sharp, or Trane.
Our teams operate daily in Montreal, Laval, Longueuil, on the North Shore and the South Shore , offering precise diagnostics and lasting repairs .

Thanks to our approach based on measurement, technical rigor and transparency, we ensure each client optimal comfort, maximum energy efficiency and the peace of mind that professional maintenance offers.