Diagnosis and repair of a broken outdoor unit in the middle of summer
At AirGreen , our HVAC technicians work daily throughout Greater Montreal to diagnose and repair wall-mounted and central heat pumps of all brands. Recently, we were called to Saint-Léonard for a complete breakdown of a Midea heat pump that refused to start when the outside temperature exceeded 30°C.
Background and symptoms observed
The client, the owner of a new condo, contacted us after noticing that his outdoor unit was no longer turning on. There was no compressor noise, no fan—but the indoor unit was displaying an error code indicating a communication anomaly . This situation is typical of internal electrical failures or voltage issues at the compressor.
Upon our arrival, we carried out a complete visual inspection :
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No visible damage to the crankcase.
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Refrigeration piping intact, with no signs of oil leaks.
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Slightly corroded electrical connections.
We then installed our digital manifold to check the refrigerant pressures, and connected our professional multimeter to the circuit board to measure the supply and control voltages.
Step 1: Electrical Check and Control Board Diagnosis
Our measurements revealed a stable input voltage, but no output to the compressor—a sign that the main board was no longer giving a start command. Further inspection confirmed the presence of a burnt component on the circuit board, likely due to a power surge caused by a recent thunderstorm.
Step 2: Refrigerant Analysis and Pressure Check
While the card was being dismantled, we took advantage of the intervention to carry out a check of the refrigeration circuit :
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Balanced static pressure: 135 psi at 30°C.
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No sign of leakage.
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Good condition of service valves and line insulation.
This allowed us to confirm that the problem was strictly electrical , and not mechanical or refrigerant related.
Step 3: Replacing the Control Board
We installed an original Midea replacement board , then reprogrammed and synchronized it with the indoor unit. After powering up, the system immediately restarted, confirming proper operation of the compressor and fan.
Our final checks:
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Low pressure: 115 psi
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High pressure: 380 psi
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Indoor blowing temperature: 12°C
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Recovery temperature: 24°C
The results were perfect: the temperature differential confirmed performance in line with factory specifications.
Step 4: Maintenance tips to prevent future breakdowns
We advised the customer to install an HVAC surge protector and perform annual preventative maintenance , including:
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Cleaning the outdoor unit.
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Checking electrical connections.
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Compressor performance test.
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Condensate drain inspection.
Final result
Thanks to this quick and methodical intervention, the Midea heat pump regained its full power. The customer immediately felt the difference: fresh, stable air, and quiet operation. This type of repair perfectly illustrates AirGreen's expertise: accurate diagnosis , safe intervention , and sustainable solutions adapted to the climate of Greater Montreal.
Why choose AirGreen in Saint-Léonard and throughout Montreal?
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Certified and experienced technicians.
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Genuine Midea parts and other major brands.
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Fast service in all areas of Montreal, Laval, the North Shore and the South Shore.
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Warranty on repairs.
Whether it's an electrical failure, a refrigerant leak or a faulty compressor, we restore your HVAC system to perfect condition, ensuring your comfort in summer and winter .