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

A broken HVAC system in the middle of the hot season

At AirGreen , we respond daily to HVAC (heating, ventilation, and air conditioning) system breakdowns across Greater Montreal. This service call came from a homeowner in Sainte-Julie , on the South Shore, whose Toshiba Carrier wall-mounted heat pump had stopped working overnight.

The outdoor unit, installed on a small back deck, was no longer turning on, leaving the interior of the home without air conditioning. The customer contacted us after noticing that the circuit breaker was consistently tripping as soon as it was turned on.

Diagnosis: an electrical power supply problem

Upon our arrival, our technician performed a complete visual inspection . The installation appeared recent, but one detail quickly caught our attention: the exterior electrical box had exposed wires, visibly exposed to the elements. This anomaly suggested a short circuit or poor contact at the compressor connection.

Here are the steps of the diagnosis:

  1. Continuity Test : We checked the wiring between the main breaker and the disconnect box. The test revealed intermittent voltage loss .

  2. Compressor inspection : terminals were in good condition, but supply voltage did not exceed 150V instead of the required 240V.

  3. Indoor control board check : no visible damage, but the start signal was not reaching the outdoor unit.

Result: the problem came from the electrical disconnect box , whose oxidized connections and poorly protected wires caused a power cut.

Repair: replacement of the case and restoration of compliance

We immediately secured the area and completely shut down the system . The disconnect box was replaced with a weatherproof, sealed model that meets CSA standards for outdoor installations.

The steps of the repair:

  • Removing the faulty housing and cleaning the wiring;

  • Complete replacement of the integrated fuse circuit breaker ;

  • Wire connection with heat shrink connectors for perfect sealing;

  • Checking that the terminals are properly tightened and applying dielectric grease;

  • Complete test of the voltage (240 V stable) and the compressor starting current.

Once the system was powered back up, the compressor started normally and quickly began producing cold air inside. No circuit breaker trips were observed after 30 minutes of continuous operation.

Result: safety restored and performance restored

The customer immediately noticed the difference: his Toshiba Carrier heat pump was once again blowing perfectly cold air , and the electricity consumption was back to normal. More importantly, the installation is now secure against any electrical hazards or water infiltration.

Our technicians also took advantage of their visit to:

  • Clean the condenser grille to improve air circulation;

  • Check the refrigerant level to ensure optimal performance;

  • Recommend an annual check of the electrical circuit , especially for outdoor units exposed to climatic variations.

AirGreen tips to avoid this type of breakdown

Power supply problems are among the most common in residential HVAC systems. To prevent them:

  • Visually inspect your outer casing every spring;

  • Avoid exposed wires or rainwater ingress;

  • Turn off the power before any handling;

  • Always have electrical repairs carried out by a certified technician .

These simple actions can extend the life of your heat pump and prevent costly breakdowns.

AirGreen: your HVAC expert on the South Shore

This intervention in Sainte-Julie illustrates our approach well: precise diagnosis, lasting repair, and safety above all .
At AirGreen, we operate throughout Montreal, Laval, Longueuil, on the North Shore and the South Shore , to ensure the performance and longevity of your Toshiba, Carrier, Fujitsu, Midea systems and several other major brands.

Whether it's an electrical problem, a refrigerant leak, a faulty compressor , or simple preventative maintenance, our certified team guarantees you professional and fast service.

AirGreen – Air Conditioning and Heating in Montreal
HVAC experts at your service, for reliable comfort all year round.
Because a well-maintained system means a worry-free summer.