A careful diagnosis for an invisible breakdown
A customer in Outremont , Montreal, contacted us after several days of sweltering heat: their Midea wall-mounted air conditioner was no longer producing cold air, although the fan still seemed to be running. This type of failure is misleading, as it suggests a minor control problem, while it often hides a deeper failure of the refrigeration circuit.
At AirGreen , we know that an accurate diagnosis makes all the difference. So our technicians went on-site to inspect the unit—a Midea mini-split wall-mounted model , designed to efficiently air condition a typical urban condo in Outremont.
Step 1: visual inspection and initial findings
As soon as the front cover was removed, one detail caught our attention:
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The evaporator coil exhibited a golden tint, characteristic of a Midea anti-corrosion coating, but also several areas of excessive condensation .
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The main electrical connection to the control module was disconnected , possibly as a result of prolonged vibration or a previous loose installation.
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Some traces of oil leakage around the copper pipes suggested a micro-leak of refrigerant.
We immediately isolated the device to prevent any short circuits and undertook a series of continuity and pressure tests.
Step 2: Complete technical diagnosis
Our certified technicians performed a refrigeration circuit check using an electronic pressure gauge. The result: lower-than-normal pressure, indicating a slow leak of R-32 refrigerant.
At the same time, the control board was tested with a multimeter — it was working correctly, confirming that the problem was indeed in the refrigeration circuit.
Key points of the diagnosis:
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Leak located at the solder of the liquid connection .
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R-32 charge level at 45% of nominal capacity.
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No compressor alert, which ruled out a failure of the outdoor unit.
Step 3: Repair and refurbishment
To restore the air conditioner to optimal performance, our team proceeded as follows:
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Complete purge of residual refrigerant in a certified recovery unit.
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Disassembly and cleaning of the leak area with dry nitrogen.
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Complete re-brazing of the copper fitting and leak test at 300 psi .
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Recharge the system with R-32 refrigerant according to Midea specifications.
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Complete cleaning of the coil and steam turbine to maximize heat exchange.
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Recommissioning and full performance testing: air outlet temperature at 8°C and perfect balanced pressure.
Step 4: Final check and advice to the client
The client immediately noticed a dramatic improvement. The room temperature dropped from 27°C to 22°C in less than 20 minutes.
We then took the time to explain to him the warning signs of a refrigerant leak :
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Slight whistling noise from the indoor unit.
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Ice formation on the coil.
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Warm air despite the fan being on.
We also recommended our AirGreen annual maintenance program , which includes:
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Inspection of the gas circuit.
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Cleaning the coil and turbine.
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Checking the electronic card.
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Calibrating the temperature sensor.
AirGreen Expertise: Precision at the Service of Comfort
This repair perfectly illustrates the rigor with which we handle each service call, whether in Montreal, Laval, Longueuil, on the North Shore or the South Shore . Our AirGreen technicians are proficient in Midea technology as well as those of major partner brands — Gree, Fujitsu, Sharp, Hitachi, Lennox, Goodman, Trane — and work on wall-mounted, multi-zone or central systems .
By restoring this Midea wall-mounted air conditioner in Outremont, we gave our client complete comfort and the peace of mind of knowing that their HVAC system is ready for Montreal summers.
AirGreen – Your expert in wall-mounted air conditioner repair in Montreal, Laval, North Shore and South Shore.