Home » Some of Our Service Calls in Greater Montreal » Repair of a Tosot wall-mounted heat pump in Côte-des-Neiges–Notre-Dame-de-Grâce
Réparation d’une thermopompe murale Tosot à Côte-des-Neiges–Notre-Dame-de-Grâce
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Repair of a Tosot wall-mounted heat pump in Côte-des-Neiges–Notre-Dame-de-Grâce

Sudden breakdown accurately diagnosed by the AirGreen team

At AirGreen , we are often called to intervene on wall-mounted heat pump breakdowns in urban areas, particularly in Montreal . Recently, our team went to the Côte-des-Neiges–Notre-Dame-de-Grâce neighborhood to resolve a problem with a Tosot Inverter wall-mounted heat pump , installed on a brick wall of a typical duplex in the area.

The customer noticed that their system had not been producing heat or cold for several days, despite the power indicator being on. An unusual clicking noise during startup suggested an internal electronic or electrical problem.

Initial inspection: assess, secure and diagnose

Upon our arrival, our certified technician carried out a complete inspection of the Tosot outdoor unit , securely mounted on galvanized wall brackets. The location, well cleared, facilitated access for diagnosis.

The first checks focused on:

  • Power supply and disconnect box ;

  • Voltage control at the compressor input terminal;

  • The condition of the fan and condenser ;

  • The electronic control board , suspected of being the cause of the malfunction.

A clamp meter test revealed no compressor start current , although the supply voltage was correct—a clear sign of a faulty start relay or damaged power board .

Diagnosis confirmed: damaged power board

After disassembling the side panel, visual analysis confirmed the presence of a slight burn mark on the printed circuit board of the power board. This type of failure can occur following an electrical surge , often caused by a variation in the network or by poor grounding.

Our team then communicated the diagnosis to the client and explained the two options:

  1. On-site repair with replacement of the card with an original Tosot part;

  2. Complete replacement of the external module , in case other components have suffered collateral damage.

The customer chose the targeted repair , which was more economical and faster, since the rest of the system was in excellent condition.

Technical intervention: precision and reliability

Our technician performed the following steps:

  1. Complete cut-off of the power supply to secure the work area;

  2. Careful removal of the defective power board ;

  3. Installation of a new certified Tosot card , corresponding to the serial number of the Inverter model;

  4. Complete check of communication connections between indoor and outdoor units;

  5. Controlled start-up test and measurement of R410A refrigerant pressures.

Once the board was replaced, the heat pump restarted immediately. The compressor resumed its cycle, the outdoor fan activated, and the indoor unit quickly distributed stable, temperate air.

Result: restored comfort and optimal performance

The Tosot system has regained its original efficiency . In air conditioning mode, the measured temperature differential reached 11°C between the incoming and outgoing air , a clear sign of restored efficiency.
We also performed a fine calibration of the fan speed to optimize airflow and reduce operating noise.

Before concluding the intervention, our technician:

  • Cleaned the outdoor condenser with compressed air;

  • Checked the wall mounting to ensure the stability of the installation;

  • And provided some maintenance advice to the customer, including the importance of spring maintenance to prevent dust and moisture buildup on the control board.

AirGreen tips for extending the life of a Tosot heat pump

Our experts recommend:

  • Have the system inspected at least once a year by a qualified technician;

  • Use a surge protector to protect sensitive electronic components;

  • Avoid obstructing air circulation around the condenser;

  • And clean the interior filters every four to six weeks during the air conditioning season.

Simple preventative maintenance can often prevent costly breakdowns and ensure the longevity of your HVAC system.

A typical intervention of our expertise in Montreal

At AirGreen , every service call is an opportunity to demonstrate our rigor and our passion for the profession.
We work on all types of HVAC systems — wall-mounted heat pumps, central air conditioners, MultiZone and VRF systems — throughout Montreal, Laval, Longueuil, the North Shore and the South Shore .

Our commitment:

  • Fast and accurate diagnosis ;

  • Guaranteed original parts ;

  • Professional and transparent service , with no unpleasant surprises.

Conclusion: a refurbished Tosot system and a reassured customer

Thanks to a targeted and methodical intervention , the Côte-des-Neiges customer's Tosot heat pump has regained its full performance.
The system now ensures constant comfort and optimal energy efficiency , even on the hottest days.

At AirGreen , we pride ourselves on bringing our customers' HVAC systems back to life, one diagnosis at a time.