Rapid intervention in an elegant residence in west-central Montreal
One June morning, our AirGreen team was called out for a service call in Westmount , one of the greenest residential neighborhoods on the island of Montreal. The client, the owner of a renovated century-old home, had noticed that his Tosot wall-mounted heat pump was no longer heating properly in reverse-cycle mode.
The device, installed above a door leading to a wooden deck, displayed an intermittent error code and a clicking noise upon startup.
Fault diagnosis: faulty communication card
Upon our arrival, our certified technician performed a series of electrical and electronic tests . The power supply voltage was stable at 240V, but the main board indicator light showed a flashing pattern characteristic of a communication problem between the indoor unit and the outdoor condenser.
Using our proprietary diagnostic module, we confirmed that the internal PCB was no longer transmitting the start signal to the compressor. This failure, quite common on previous generation Tosot units, often occurs after a power surge or moisture infiltration.
Complete repair and performance optimization
Step 1: Replacing the electronic card
We have replaced the Tosot control board with a revised and updated version, directly approved by the manufacturer. This operation requires fine calibration to ensure compatibility between the indoor unit and the outdoor module.
Step 2: Complete cleaning of the interior coil
Taking advantage of the hood opening, our technician proceeded to steam clean the coil and the tangential fan . This step improves air circulation and eliminates dust deposits that could affect the temperature sensors.
Step 3: Full Performance Test
After resetting and synchronizing the modules, the Tosot heat pump was started. We measured a stable supply air temperature of 11°C in cooling mode and a nominal current consumption within the factory specifications.
The initial clicking noise was gone, proving that the faulty card was indeed the cause of the problem.
Comfort restored and reliability assured
The customer immediately felt the difference: the heat pump was operating at full capacity, with constant airflow and regulated temperature. We also scheduled a Tosot firmware update to optimize internal communication and reduce the risk of similar failures in the future.
At AirGreen , we view every service as an opportunity to optimize the performance of an HVAC system, not simply to repair it.
AirGreen Recommendations to Extend the Life of a Tosot Heat Pump
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Protect the unit against power surges : a dedicated differential circuit breaker or surge protector prevents damage to electronic boards.
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Perform annual preventative maintenance : cleaning, checking connections and pressure testing helps detect problems before they cause a breakdown.
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Maintain good clearance around the indoor unit : avoid obstructing air inlets with curtains or furniture, especially in rooms with access to the outside.
Our HVAC repair, maintenance and optimization services cover all of Greater Montreal , including Laval, Longueuil, the North Shore and the South Shore .
The AirGreen commitment: precision, transparency and technical excellence
Every repair performed by AirGreen meets the highest industry standards.
Our technicians are certified by the RBQ and trained according to the guidelines of the manufacturers Tosot, Gree, Midea, Fujitsu and Sharp.
Whether your system has an electronic failure , a refrigerant leak , or a drop in energy efficiency , we provide complete and lasting service — with guaranteed genuine parts.
Warning:
Repairs to electronic boards and manipulation of live circuits should only be carried out by certified refrigeration and electrical professionals. Any unqualified attempt may cause short circuits or irreversible damage to the device.