Repair of a Hexzair heat pump in Sainte-Thérèse

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.

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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:

• Voltage and continuity on the main control board.

• Communication signal between indoor and outdoor unit.

• Condition of the starting capacitor , often responsible for compressor blockages.

• 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.

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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:

• The compressor started immediately.

• The outdoor fan has returned to its nominal speed.

• 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.

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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:

• Clean the internal filters at least once a month.

• Free up space around the outdoor unit to ensure good ventilation.

• Perform annual HVAC maintenance to prevent premature deterioration of electronic components.

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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.

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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:

• Accurate diagnostics using the latest generation of electronic tools.

• Original or equivalent quality parts .

• Durable repairs , always compliant with current HVAC safety standards.

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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.