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

A heat pump sheltered, but in distress

At AirGreen , we were called to repair a Carrier wall-mounted heat pump in Boisbriand , on the North Shore. The customer, concerned about protecting their unit from the elements, had their outdoor condenser installed under an enclosed balcony. While this configuration provides some protection from snow, it also limits airflow , which can cause performance issues.

The customer noticed that the unit was no longer defrosting properly in the winter and was producing an intermittent metallic noise during each defrost cycle. This symptom could indicate a sensor problem or an airflow obstruction , two common causes in this type of semi-enclosed installation.

Complete inspection and diagnosis

1. Visual and mechanical inspection

Upon arrival, we observed an accumulation of dead leaves and debris around the condenser, partially blocking the air outlet. The coils showed persistent traces of frost , despite an active defrost mode. This immediately pointed our diagnosis towards an imbalance in the defrost cycle .

2. Electronic analysis

Using a multimeter and a Carrier code reader, we found that the defrost sensor was sending incorrect readings to the control board . The control board was misinterpreting the coil temperature, triggering the defrost cycle too early (or too late).

Further inspection revealed that the probe had been damaged by moisture from condensation trapped under the structure.

3. Pressure and flow tests

We then measured the suction and discharge pressures of the refrigeration circuit. The values ​​were within the normal range, ruling out any refrigerant leaks. However, the insufficient airflow amplified the formation of ice on the coil. The condenser, installed too close to the rear wall, lacked clearance for optimal ventilation.

Repair and readjustment of the installation

1. Replacing the defrost sensor

We replaced the thermistor probe with an original Carrier model, ensuring perfect compatibility with the existing electronic board. Once the part was installed, we recalibrated the automatic defrost cycle via the control module.

2. Cleaning and clearing the condenser

A thorough steam cleaning of the coils removed dust, leaves, and moisture deposits that were impeding heat exchange. We also advised the client to install a side guard to prevent debris from re-accumulating while maintaining sufficient airflow.

3. Location reconfiguration

Although the condenser is sheltered, we recommended slightly offsetting the unit (about 20 cm) to increase airflow. This small adjustment significantly improved the static flow pressure , resulting in better efficiency and more stable defrosting.

Results and performance after intervention

After the repair, we tested the heat pump for a full cycle. Results:

  • Indoor blowing temperature : 34°C in heating mode.

  • Defrosting time : reduced from 9 to 4 minutes.

  • Mechanical noise : completely eliminated.

The customer immediately noticed increased heating stability and reduced power consumption , a sign of more efficient operation.

AirGreen Tips for Sheltered Installations

Wall-mounted heat pump installations under closed structures require some special precautions:

  1. Maintain a minimum clearance of 30 to 45 cm behind and above the unit.

  2. Clean the coils regularly and remove any leaves or cobwebs.

  3. Check the defrosting at the beginning of every winter to prevent ice buildup.

  4. Avoid confined spaces : the expelled heat must dissipate freely.

At AirGreen, we often see this type of configuration on the North Shore , particularly in Boisbriand, Blainville and Sainte-Thérèse , where homeowners are looking to protect their systems from snow. While this is a good intention, it is important to ensure that the condenser ventilation remains optimal to avoid performance issues.

AirGreen: expertise and rigor in every HVAC repair

Every service we perform is an opportunity to ensure the durability and energy efficiency of our customers' HVAC systems. Whether it's a Carrier , Fujitsu , Midea , or Gree heat pump, our certified technicians ensure each unit operates to the highest standards on the market.

We operate throughout Montreal, Laval, Longueuil, on the North Shore and the South Shore , with fast, professional and personalized service.

At AirGreen, every repair is also an improvement .