Sudden heating failure precisely resolved by AirGreen
At AirGreen , every HVAC service call is an opportunity to demonstrate our expertise and rigor. This project in Outremont involved a Mitsubishi Electric wall-mounted heat pump that was no longer producing heat in early fall, despite the indoor fan starting normally.
Symptoms observed by the client
The client, owner of a typical Outremont duplex, reported the following points to us:
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The interior airflow remained cool , even in heating mode;
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The Mitsubishi outdoor unit seemed to work intermittently ;
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No visible errors on the wall unit, but abnormally long reaction time when changing modes.
Our team quickly scheduled an on-site diagnostic visit , aware that such anomalies can come from a lack of refrigerant as well as a reversing valve problem .
Initial inspection and system analysis
The outdoor unit, a Mitsubishi Electric MUZ-FH model, was installed on raised supports, well away from the brick wall, ensuring adequate air circulation. However, a careful inspection revealed:
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A buildup of dust on the condenser;
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Traces of oil at a flare connection in the refrigerant circuit;
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Abnormally low pressure at the service intake, a sign of a micro-leak of refrigerant .
Steps of the intervention
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Complete load and pressure verification using calibrated digital pressure gauges.
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Application of an electronic leak detector (halogen type) around the connections. The device immediately confirmed the presence of refrigerant gas near the lower connection.
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Bleeding and tightening of the flare fitting , followed by replacement of the copper gasket to ensure a perfect seal.
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Completely evacuate the system to -30 inHg to eliminate all traces of moisture.
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Recharge with R410A refrigerant according to the exact specifications of the Mitsubishi Electric manufacturer.
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Performance test : After restarting, the indoor blowing temperature quickly rose to 38°C , confirming that heating had resumed.
Results and validation
Once the repair was completed, our technicians proceeded to:
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Checking air flow and power consumption;
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Control of operating pressures in heating and air conditioning mode;
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Confirmation of tightness using a high-sensitivity foaming solution.
The measurements were perfect: the heat pump regained its original performance, and the customer noted an immediate difference in thermal comfort .
AirGreen Recommendations
To prevent such a problem from recurring, we recommended:
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An annual inspection of all flare fittings ;
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Preventive cleaning of the condenser to avoid overheating;
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A vacuum and charge check before each recharge, in order to preserve the Mitsubishi compressor, renowned for its precision but sensitive to pressure imbalances.
We also emphasized the importance of regular HVAC system maintenance , especially before transition seasons (spring and fall), when mode changes are more frequent.
An exemplary intervention by AirGreen
This type of micro-leak, often imperceptible to the naked eye, can ultimately compromise the performance of a heat pump, lead to increased energy consumption and reduced compressor life. Thanks to our advanced diagnostic equipment and the ongoing training of our technicians, AirGreen ensures fast, accurate and long-lasting repair service .
The Outremont customer has regained not only the warmth, but also the confidence that comes with a Mitsubishi Electric system operating at its full potential .
In conclusion
This Mitsubishi Electric wall-mounted heat pump repair in Outremont perfectly illustrates the AirGreen philosophy: responding quickly, diagnosing accurately and offering sustainable solutions that combine performance and comfort.
At AirGreen , we proudly serve all of Greater Montreal, Laval, Longueuil, the North Shore and the South Shore , with a constant commitment to quality and the satisfaction of each customer.