A heat pump in distress on the edge of the lake
At AirGreen , we often receive urgent calls during seasonal changes, when heat pumps need to alternate between heating and cooling. This was recently the case in Sainte-Anne-de-Bellevue , on the western tip of the island of Montreal. Our team was contacted by a homeowner whose Mitsubishi Electric wall-mounted heat pump was no longer working properly: the outdoor unit refused to start, leaving the house without air conditioning despite the heat.
Initial diagnosis: a compressor that no longer starts
Upon our arrival, our technician inspected the Mitsubishi Electric Hyper Heat outdoor unit, well known for its efficiency in cold climates. At first glance, the unit appeared intact, but an abnormal noise was coming from the compressor.
The first steps of diagnosis included:
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Power supply check : stable voltage at 240V confirmed.
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Indoor control board signal check : communication present.
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Start capacitor test : abnormal results, capacity reduced by 70%.
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Visual inspection of the wiring : no traces of oxidation or rodents.
The verdict quickly became clear: the main compressor capacitor was defective , preventing the engine from starting.
On-site repair: capacitor replacement and complete cleaning
We replaced the original Mitsubishi Electric capacitor , a part compatible with the Hyper Heat heat pump model.
This step was followed by a thorough cleaning of the condenser : the top of the unit was covered with dust and debris, reducing the efficiency of the fan.
The steps taken:
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Safe disconnection and insulation test.
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Removing the top cover and side panel.
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Installation of the new capacitor (same voltage and capacity).
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Clean the coil with gentle steam to remove accumulated dirt.
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Checking the airflow and fan after reassembly.
Result: performance and comfort restored
Once the capacitor was replaced, the heat pump restarted immediately.
We measured:
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Stable refrigerant pressure at 125 psi,
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Indoor blowing temperature of 11°C,
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Normal power consumption , without compressor overload.
The relieved customer found uniform freshness throughout the house . He was surprised to see how a simple component could cause a complete breakdown.
AirGreen Recommendations for Extending the Life of a Heat Pump
To prevent this type of breakdown from happening again, our experts recommend:
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Annual preventative maintenance including condenser cleaning, pressure check and electrical inspection.
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Monitor for unusual noises : A quiet compressor is a sign of proper operation.
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Protection of the outdoor unit against dust, leaves and physical shocks.
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Check drainage to prevent water accumulation on the base of the unit.
At AirGreen, we know that Mitsubishi Electric heat pumps are among the most reliable on the market, but like any HVAC system, they require careful monitoring.
Why choose AirGreen for your HVAC repairs in Montreal and on the North and South Shores
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Mitsubishi Electric certified technicians trained to quickly diagnose each component.
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Genuine parts guaranteed and installed according to manufacturer standards.
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Fast and professional service , available everywhere in Montreal, Laval, Longueuil, the North Shore and the South Shore .
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Complete transparency on costs and interventions carried out.
A repair that illustrates our HVAC expertise
This intervention in Sainte-Anne-de-Bellevue demonstrates once again the rigor and precision of our approach.
We don't just repair: we restore performance and peace of mind.
Every AirGreen service call is an opportunity to preserve the durability and energy efficiency of your HVAC system, whether it's a Mitsubishi Electric wall-mounted heat pump , a multi-zone system, or a central heat pump .