When performance drops in the middle of a Quebec winter
At AirGreen , we often receive urgent service calls during the bitter cold of January. This is exactly what happened in Sainte-Julie , where a customer contacted us after noticing that their Trane XE15 central heat pump was no longer heating efficiently. Despite a thermostat set at 22°C, the indoor temperature was stagnating around 18°C, and the outdoor fan seemed to be struggling under a layer of snow.
Our team responded quickly to diagnose the source of the problem and restart this Trane system, renowned for its reliability—but which, like any HVAC unit, requires regular maintenance to withstand the harsh winters of Quebec.
On-site diagnosis: ice accumulation and defective sensor
Upon arrival, we noticed several typical signs of a faulty defrost cycle :
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Visible accumulation of ice on the outdoor condenser ;
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Abnormal noise from the compressor , a sign of excessive effort;
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Abnormally low pressure measured on the discharge line;
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Defrost sensor (thermistor) dirty and inoperative.
These symptoms indicated that the heat pump remained stuck in heating mode without initiating its defrost cycle, which led to a gradual loss of performance and excessive electricity consumption.
AirGreen intervention: defrosting, cleaning and complete calibration
Our technician undertook a complete defrost of the condenser using a hot air system, then carefully cleaned the heat exchange fins. We then:
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Replaced the faulty thermistor responsible for triggering the defrost cycle.
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Checked the R-410A refrigerant charge , slightly below the optimal threshold; precise top-up was carried out.
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Cleaned the coils and fan compartment to improve airflow.
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Reprogrammed the control board to adjust the defrost cycle frequency based on outdoor conditions.
All of these actions allowed the Trane XE15 heat pump to regain its full thermal capacity while optimizing its energy efficiency.
Result: comfort restored and efficiency restored
After restarting, we measured:
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A blowing temperature of 37°C , i.e. a gain of +8°C compared to the initial state;
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A stabilized nominal compressor current , indicating balanced operation;
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A defrost cycle now regular, approximately 10 minutes every 90 minutes in freezing weather.
The customer immediately noticed the difference: more even heat, a quieter system, and an expected 10% to 15% reduction in electricity consumption .
AirGreen tips to prevent this type of breakdown
Central heat pumps like the Trane XE15 are designed to provide year-round comfort, but they require rigorous seasonal maintenance, especially in Quebec where winters are long and wet. To avoid defrost failures:
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Clear the snow around the condenser (minimum 60 cm free).
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Have the thermistor and relays checked before winter.
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Clean outdoor coils in the fall and spring.
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Schedule annual AirGreen maintenance , including checking refrigerant, pressures and overall performance.
Preventative maintenance costs a fraction of the cost of an emergency repair and extends the life of your appliance.
AirGreen expertise at your service in Sainte-Julie and throughout the South Shore
Whether you live in Sainte-Julie , Boucherville , Brossard or Saint-Bruno , our certified technicians respond quickly for any central heat pump repair , HVAC fault diagnosis , or seasonal maintenance .
We work with the biggest brands: Trane, Fujitsu, Midea, Gree, Sharp, Goodman, Lennox, Zephyr , and more. Every job is carried out to the highest quality standards, with precise diagnostic tools and a constant focus on energy efficiency.
At AirGreen, we believe that the reliability of your comfort depends on the skill of those who maintain it. Whether your system is old or new, we ensure it operates at its full potential, even on the worst winter days.