When a wall-mounted air conditioner stops blowing cold in the heart of Pointe-Claire
At AirGreen , we often receive calls from concerned customers when their wall-mounted air conditioner suddenly stops cooling. Recently, a resident of Pointe-Claire , in the west end of Montreal, contacted us about his Hitachi wall-mounted system , which was no longer producing cold air, despite a working outdoor compressor.
Our team of certified technicians arrived on site the next morning to perform a complete system diagnosis .
Diagnosis: A typical problem but not to be ignored
At first glance, the wall-mounted unit appeared intact: no apparent leaks or unusual noise. However, upon switching it on, a stream of warm air came out of the diffuser. After opening the front panel, we noticed that the evaporator fins were covered in a thin layer of dust and that the internal temperature sensor was not responding correctly.
Our checks revealed two essential elements:
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The thermistor sensor wire had lost conductivity due to oxidation.
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The R-410A refrigerant level was slightly below the optimal pressure.
On-site repair: AirGreen precision and reliability
Once the problem was identified, our team thoroughly cleaned the indoor unit using specialized, non-corrosive products. The thermistor sensor was replaced with a genuine Hitachi part, ensuring accurate readings of ambient temperatures.
We then checked the outside pressures and added the exact amount of refrigerant needed to restore the compressor to nominal performance.
A full operating cycle test confirmed that the air conditioner was back to full efficiency:
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Homogeneous cold air at 7°C at the evaporator outlet
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Reduced noise after cleaning the tangential fan
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No leaks detected on flare fittings
An intervention that illustrates the importance of regular maintenance
This type of intervention is a reminder of how crucial it is to have your wall-mounted system serviced at least once a year . Dust accumulated on the coils, dirty sensors and micro-leaks of refrigerant are often the cause of a gradual decline in energy efficiency .
At AirGreen , we offer preventative maintenance programs tailored to each brand: Hitachi, Sharp, Fujitsu, Midea, Gree, and many others . These regular visits allow:
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to extend the life of devices,
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to avoid summer breakdowns,
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and reduce electricity consumption by up to 20%.
Result: comfort restored and customer reassured
At the end of the intervention, our technician took the time to explain to the customer the correct maintenance procedures:
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clean the filter every month during the warm season,
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maintain sufficient clearance around the indoor unit,
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and avoid sudden variations in the setpoint.
Upon restarting, the room temperature dropped from 27°C to 22°C in less than 15 minutes. The customer, delighted to regain comfort, also subscribed to our annual AirGreen maintenance program .
Why use AirGreen for wall-mounted air conditioner repair in Montreal and surrounding areas?
We respond quickly throughout Greater Montreal , including Laval, Longueuil, the North Shore and the South Shore , to diagnose and repair any type of residential or commercial HVAC system .
Our technicians have the latest tools—electronic vacuum pumps, digital leak detectors, connected pressure gauges—to ensure long-lasting repairs that comply with Quebec's environmental standards.
AirGreen is the promise of a service:
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fast , thanks to our mobile fleet distributed across all metropolitan areas;
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professional , provided by CMMTQ certified technicians;
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transparent , with precise diagnoses and clear explanations.
In summary
This Hitachi wall-mounted air conditioner repair in Pointe-Claire demonstrates our expertise and commitment to quality. Whether it's a refrigerant leak, a faulty sensor, or a lack of maintenance, we do everything we can to restore our customers' indoor comfort quickly and efficiently .