A service call for a wall-mounted heat pump that refused to start
At AirGreen , we regularly receive calls for wall-mounted heat pump breakdowns during the changing seasons, when HVAC systems switch from heating to cooling mode. Recently, we were contacted by a client in Sainte-Thérèse , on the North Shore , about a Hexzair outdoor unit that was no longer starting, leaving the home without thermal comfort.
Initial diagnosis: a system blocked at startup
Upon arrival, we noticed that the Hexzair heat pump (wall-mounted model, single-zone unit) appeared to be in good visual condition: no apparent leaks, no frost, and correct power supply voltage. However, the compressor would not engage , and the outdoor fan remained stationary.
Our technicians carried out a series of checks:
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Voltage and continuity on the main control board.
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Communication signal between indoor and outdoor unit.
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Condition of the starting capacitor , often responsible for compressor blockages.
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Refrigeration circuit pressures , to exclude a refrigerant leak or imbalance.
Diagnostics revealed that the start capacitor was faulty , which was preventing the compressor from turning on.
Intervention: capacitor replacement and complete test
We replaced the capacitor with a model that met Hexzair specifications and then checked that the compressor started correctly and that the pressure was rising. Once the part was replaced:
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The compressor started immediately.
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The outdoor fan has returned to its nominal speed.
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Discharge and return temperatures were stable and within recommended ranges.
Our technicians then checked the inrush current , the operation of the electronic expansion valve , and the interior blowing temperature , which quickly dropped below 15°C — proof of optimal performance.
Preventive maintenance and customer advice
Before leaving the premises, we carried out a complete cleaning of the condenser , which was often clogged with dust and debris accumulated on the balcony. We also advised the client:
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Clean the internal filters at least once a month.
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Free up space around the outdoor unit to ensure good ventilation.
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Perform annual HVAC maintenance to prevent premature deterioration of electronic components.
Result: restored comfort and optimized performance
Thanks to this rapid intervention , the customer's Hexzair heat pump is now operating at full capacity. The house has regained stable thermal comfort , with controlled energy consumption .
This type of failure is common on systems over 5 years old, but an annual inspection can often detect weak capacitors or electronic boards before they cause complete failure.
AirGreen expertise: reliability and transparency at every stage
At AirGreen , every service call is handled with rigor and transparency. Our team of certified technicians covers the entire North Shore , including Sainte-Thérèse, Blainville, Boisbriand and Terrebonne , and works on all popular brands such as Hexzair, Fujitsu, Midea, Gree, Sharp, Lennox and Trane .
We guarantee:
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Accurate diagnostics using the latest generation of electronic tools.
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Original or equivalent quality parts .
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Durable repairs , always compliant with current HVAC safety standards.
A trusted partner for your HVAC systems
Whether for an urgent repair , preventative maintenance , or a complete heat pump installation , AirGreen remains a trusted partner for residents of the North Shore, Laval, Montreal and the South Shore .
Your comfort is our mission — and your satisfaction, our guarantee.