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Réparation d’une thermopompe murale Midea à Saint-Eustache
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Repair of a Midea wall-mounted heat pump in Saint-Eustache

When a loss of efficiency hides a refrigerant leak

At AirGreen , we frequently receive calls from customers who notice a gradual decline in the performance of their heat pump, especially during cold weather. In Saint-Eustache , our team was called about a Midea wall-mounted heat pump that, according to the owner, had been "blowing lukewarm air" for just a few days.

The customer had tried restarting his unit without success. The unit worked, but the indoor temperature never rose above 19°C. For a system meant to heat an entire house, this was a clear sign that a refrigerant or compression issue needed to be checked.

AirGreen Diagnosis: Leak on the suction line

On site, our technician carried out a complete diagnosis. After a pressure check, the values ​​indicated an abnormally low pressure , typical of an R-410A refrigerant leak .

Here are the findings:

  • No errors on the electronic card;

  • Compressor functional but pressures too low ;

  • Oil visible on low pressure service valve;

  • Traces of microleaks at the flare junction .

Using an electronic leak detector , we confirmed that the refrigerant was slowly leaking at this exact point. This type of leak is common after several thermal cycles if the fittings are not tightened to the correct torque at the time of installation.

Technical intervention: repair and complete recharge of the circuit

Our standard repair procedure for this type of intervention was as follows:

  1. Safe recovery of remaining refrigerant using an approved cylinder.

  2. Replacing Schrader valves to eliminate any future leaks.

  3. Tighten and recalibrate the flares according to the recommended Midea tightening torque (18 to 25 N m).

  4. Nitrogen leak test at 400 psi for 30 minutes – no pressure drop observed.

  5. Creation of a perfect vacuum at -760 mmHg using a double-stage vacuum pump.

  6. Complete recharge with R-410A refrigerant to the exact amount indicated on the unit's nameplate.

  7. Checking subcooling and superheat , ensuring optimal performance.

Result: restored performance and maximum efficiency

After recharging, we restarted the system and observed the following results:

  • Blowing temperature: 34°C in heating mode;

  • Pressure stabilized at 125 psi on low and 365 psi on high ;

  • No leaks detected after 15 minutes of continuous observation;

  • Reduced compressor noise and smooth operation.

The client immediately noticed a rapid return of heat and thermal stability throughout the house.

AirGreen Tips to Avoid Refrigerant Leaks

Leaks on Midea wall-mounted heat pumps may seem minor, but they cause:

  • A significant drop in energy efficiency ;

  • Premature wear of the compressor ;

  • Increased electricity consumption .

To avoid them, we recommend:

  • An annual inspection of the refrigeration circuit;

  • Tightening the flares at each maintenance;

  • Installation of sealing caps with O-rings ;

  • Regular cleaning of the coils to maintain good heat exchange.

These simple actions can extend the life of your heat pump by several years.

AirGreen: your HVAC partner on the North Shore and in Montreal

At AirGreen , we combine technical expertise and professional rigor to provide repair and maintenance for all popular brands: Midea, Fujitsu, Gree, Sharp, Trane, Goodman, Lennox, Zephyr , and many more.

Our technicians are certified to respond quickly in Montreal, Laval, Longueuil, the North Shore and the South Shore , with original parts and the latest generation diagnostic tools.

The end result: a fully functioning Midea heat pump, a comfortable home again, and a homeowner satisfied with having regained optimal energy efficiency.

At AirGreen, we repair, maintain, and protect your comfort—summer and winter.