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Réparation d’une thermopompe murale Daikin à Rosemère
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Repair of a Daikin wall-mounted heat pump in Rosemère

Fast diagnosis and expert repair for restored performance

At AirGreen , we were recently mandated for an HVAC service call in a single-family residence in Rosemère , on the North Shore of Montreal. The client, owner of a Daikin wall-mounted heat pump , had noticed that his outdoor unit was no longer turning on despite a thermostat set at 22°C. With the summer heat, this failure quickly threatened indoor comfort.

Our goal: to identify the exact cause of the failure and put the system back into service as quickly as possible , while guaranteeing the original performance of the device.

First on-site inspection

Upon our arrival, we carried out a complete check of the Daikin compressor installed on a wooden terrace (see photo).
Here are our first observations:

  • The outdoor unit was receiving power , but would not start.

  • No relay or compressor noise was heard.

  • The customer had already tried to reset the circuit breaker , without success.

  • The lights on the indoor circuit board were flashing, indicating a communication error between the indoor and outdoor units.

Technical diagnosis

Our AirGreen certified technician started by checking the supply voltage at the wall circuit breaker outlet : the voltage was stable at 240V, ruling out a power failure.

We then tested the continuity of the communication wiring between the indoor unit and the Daikin condenser. A resistance test revealed a partially severed wire near the outdoor connector , caused by wear from vibration and moisture. This type of damage is common when the cable is not perfectly secured or insulated from the deck floor.

Repair carried out

The intervention consisted of:

  1. Disconnect the power supply to ensure complete safety during handling.

  2. Replace the damaged section of communication cable with high quality shielded wire compatible with Daikin units.

  3. Check the integrity of the connections and apply a dielectric protector to prevent future corrosion.

  4. Restart the system and observe the behavior of the compressor and fan.

  5. Monitor operating pressures and temperatures for 20 minutes to validate cooling efficiency.

Results obtained

Once the connection was reestablished, the Daikin unit started immediately.
The measurements obtained were excellent:

  • Low pressure: 115 psi

  • High pressure: 380 psi

  • Blown air temperature: 8.4°C

  • Room temperature: 23.7°C

➡️ 15°C difference between supply air and ambient air — proof of optimal performance .

The customer was able to see in real time the resumption of cooling in his living room, and the device maintained a stable temperature throughout the observation period.

Advice given to the client

We took advantage of the visit to offer some preventive recommendations:

  • Visually check outdoor cables once or twice a year, especially if they are exposed to the weather.

  • Avoid placing heavy objects or walking on wires around the condenser.

  • Schedule a complete annual maintenance including cleaning the coils and checking the refrigerant pressure.

These simple actions can significantly extend the lifespan of a Daikin wall-mounted heat pump while maintaining its maximum energy efficiency.

AirGreen Expertise: The Difference That Can Be Measured

Every AirGreen repair is based on three pillars:

  1. Precision diagnosis : our technicians identify the exact cause before any intervention.

  2. Durable repair : exclusive use of parts and wiring approved by manufacturers.

  3. Transparent follow-up : clear explanation of the problem, the work carried out and the results measured.

Thanks to this rigorous approach, our customers in Montreal, Laval and on the North Shore benefit from reliable, honest and efficient HVAC service .

Details of the intervention

Element Description
Device type Daikin wall-mounted heat pump
Place Rosemère (North Shore)
Initial problem Outdoor unit no longer started
Diagnosis Damaged communication wire
Repair Cable replacement, dielectric protection
Result System rebooted, optimal performance restored

Conclusion

Thanks to a quick and methodical intervention, AirGreen allowed a Rosemère family to regain the comfort of their home by repairing a subtle but critical electrical fault on their Daikin wall-mounted heat pump .
Once the wiring was replaced and the connections protected, the system performed like new, providing efficient and quiet cooling.

AirGreen is the benchmark in heat pump and HVAC system repair in Montreal, Laval and on the North Shore , for uncompromising comfort and impeccable service.