A precise diagnosis for a subtle electrical fault
At AirGreen , we were recently called for HVAC repair service in Sainte-Dorothée (Laval) . The customer reported a Gree wall-mounted heat pump that refused to start despite apparent power. This type of breakdown, while common, requires a methodical approach—and this is precisely what sets our team apart: thorough diagnosis before any intervention.
Context of the intervention
The residence in question is a recently built single-family home with a Gree Inverter system. The customer contacted us after noticing that the outdoor heat pump was no longer responding , with no compressor noise or light signal. Before our arrival, she had already checked the circuit breakers—without success.
Our certified technician therefore undertook a complete check of the electrical circuit , starting with the connection box of the outdoor unit.
Step 1: Checking voltages and continuities
On site, using a calibrated digital multimeter , we measured the voltages between terminals L1, L2 and neutral.
Result: no voltage detected on the main board , while the panel power line showed 240V.
➡️ Preliminary diagnosis: break in continuity between the disconnection box and the outdoor unit.
We then removed the condenser service plate, where a slightly oxidized cable on the neutral showed visible heating at the terminal . This type of anomaly, if left untreated, can cause intermittent failure or complete compressor failure.
Step 2: Wiring Correction and Functional Test
After cleaning the oxidized terminal , replacing the faulty terminal and tightening all connections, we took the measurements again.
Results after repair:
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Input voltage confirmed at 240V between L1 and L2.
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Correct communication between indoor and outdoor unit (stable DC signal).
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Compressor starting current measured at 2.2 A — within nominal values for this model.
The unit then restarted normally, restoring indoor comfort within minutes.
Step 3: Complete System Check
Our technicians never limit themselves to repairing the immediate fault. Once the unit is functional, we perform a complete performance check :
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Blown air temperature: 12°C in cooling mode.
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Refrigerant pressure in accordance with the technical data sheet.
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No abnormal noise or excessive vibration.
The customer was immediately able to notice the smooth and silent restart of his Gree system, typical of well-executed maintenance and repair .
Technical analysis and recommendations
This intervention perfectly illustrates the importance of regular maintenance and preventive electrical inspection .
Continuity failures—often invisible to the naked eye—account for a significant proportion of problems with wall-mounted heat pumps.
Our recommendations to the client:
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Check electrical connections in outdoor boxes annually , especially after winter.
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Clean the units and clear the condensate drain lines.
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Schedule a complete AirGreen service every spring to avoid service interruptions during the summer heat.
Result: comfort restored and safety assured
In less than two hours, our team has:
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Diagnosed an internal continuity failure.
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Repaired the wiring and restored the correct voltage.
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Checked inter-unit communication and refrigeration performance.
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Reassured the customer about the reliability of their system.
The Gree heat pump returned to optimal performance, and the customer was able to enjoy constant comfort, with controlled energy consumption.
Why use AirGreen in Laval and on the North Shore?
Because our technicians:
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Diagnose before replacing — a cost-effective and sustainable approach.
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Are authorized and trained by major HVAC manufacturers .
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Intervene quickly in Laval, Montreal, Longueuil, North Shore and South Shore .
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Guarantee repairs that meet the highest electrical and mechanical standards .
Every AirGreen service call combines expertise, precision and transparency —values that ensure the longevity of your HVAC equipment.