A quick service call for a sudden breakdown
At AirGreen , we often receive urgent calls from customers whose wall-mounted heat pump suddenly stops working, especially as the first warm days of spring approach. This is exactly what happened in Sainte-Julie , on the South Shore of Montreal , where a homeowner contacted us after noticing that their Midea heat pump was no longer blowing cold air despite a normal light display.
This wall unit had just been installed a few weeks earlier, and the green protective tape visible on the front indicated a recent installation. The customer was concerned about a warranty issue or a manufacturing defect.
Step One: Complete Inspection of the Midea Heat Pump
Upon arrival, our technician confirmed that it was a Midea Blanc Inverter R32 series wall-mounted heat pump , a model popular for its energy efficiency and quiet operation. The outdoor unit was perfectly installed, the refrigerant connections were well insulated, and the wiring was properly secured.
The main symptom was:
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The indoor unit turned on and opened its motorized shutters.
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No airflow was noticeable.
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The outdoor compressor would not start.
These signs pointed to a communication failure or internal error detection , typical of new installations when microdetails escape the initial adjustment.
Technical diagnosis: communication problem between units
Our technicians checked the wiring between terminals 1-2-3 connecting the indoor and outdoor units. It turned out that the polarity of the communication wire was reversed between the two blocks, a rare but possible error when the system has been installed by a third party without thorough testing.
In other words, the heat pump was receiving power, but couldn't "talk" to its outdoor compressor. This type of error prevents the refrigeration cycle from starting and results in silent operation, with neither cold nor hot air.
Intervention and correction
The wiring correction was carried out on site:
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Complete disconnection from the power supply.
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Checking the polarities on the input and output terminals.
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Rewiring according to the diagrams provided by Midea (terminal 1 → terminal 1, 2 → 2, 3 → 3).
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Tighten the terminal screws with appropriate torque to prevent future loosening.
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Restart the heat pump and test the communication.
A few seconds after restarting, the outdoor compressor started , confirming that the problem was resolved. A powerful flow of cold air was quickly returned to the interior, reaching a temperature of 8.7°C at the outlet .
Preventive maintenance and customer advice
To prevent such situations from happening again, our technician took the time to explain some essential recommendations to the customer:
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Always entrust the installation and electrical connection to an RBQ certified contractor.
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Check that the communication test is performed at the end of the installation.
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Schedule an annual maintenance visit to ensure optimal compressor and fan performance.
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Do not remove any guards or filters until the complete installation has been validated.
We also checked the pressure and temperature parameters of the R-32 refrigerant, confirming stable operation and compliance with Midea values.
Result: comfort restored and warranty preserved
In less than two hours, the Midea heat pump was fully operational. The customer was able to enjoy the coolness of their home without compromising the manufacturer's warranty. The intervention, although minor, prevented a prolonged breakdown and demonstrated the importance of an accurate professional diagnosis .
At AirGreen , we respond quickly to wall-mounted heat pump repairs throughout Greater Montreal , including Sainte-Julie, Brossard, Longueuil, Laval and the North Shore . Our technicians have extensive expertise in Midea, Gree, Fujitsu, Sharp, Lennox, Trane and Goodman systems, ensuring fast, reliable and secure service.
In summary
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Device type: Midea White R32 series wall-mounted heat pump
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Problem: No communication between indoor and outdoor units
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Cause: Reversed polarity on 1-2-3 wiring
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Solution: Correct rewiring + communication test
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Result: Cold air restored, immediate comfort
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Location: Sainte-Julie, South Shore of Montreal
This intervention demonstrates that rigorous analysis and methodical diagnosis can often quickly resolve what are perceived as major breakdowns. At AirGreen, we combine technical expertise with impeccable customer service to ensure lasting comfort for our residential and commercial customers.