A silent breakdown in a Montreal apartment
Recently, a client in the Côte-des-Neiges–Notre-Dame-de-Grâce neighborhood of Montreal contacted us about a problem with their Friedrich PTAC system , installed under a bedroom window. The unit, which has a compact, integrated appearance, is typical of apartment buildings or condos : it provides both heating and cooling via a single wall-mounted module.
The problem: For several days, the system had stopped producing cold air , despite a normal display on the control panel. The customer could hear the fan, but no cooling sensation was felt—a common scenario with aging or poorly maintained PTAC units .
Diagnosis: a blocked compressor and a faulty sensor
At AirGreen , every service call begins with a thorough diagnostic. After checking the power supply and control panel settings, our technician found that the compressor was not starting , although the fan was running.
We then carried out several tests:
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Measurement of electrical voltages at the compressor terminals.
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Control board control .
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Evaporator temperature sensor test .
As a result, the temperature sensor was sending false data to the board, preventing it from starting the cooling cycle. In addition, the compressor start relay was showing signs of fatigue, with abnormal resistance.
Steps of repair
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Removing the front panel and air filter to access the internal electronics.
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Replaced the temperature sensor with an original Friedrich model, calibrated for the R-410A range.
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Installing a new starter relay .
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Complete cleaning of the evaporator and condenser , often neglected but essential for energy efficiency.
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Complete system test : voltage, compressor current, air outlet pressure and temperature.
In less than two hours, the integrated heat pump (PTAC) was back up to full capacity. The blown air showed a difference of 11°C compared to the ambient temperature—proof of optimal performance.
Comfort restored for the customer
The client, who lives on the third floor, immediately felt a difference. In addition to the restored freshness, we noticed a decrease in operating noise after the internal cleaning.
We advised him to take a few simple steps:
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Clean the air filter every two months.
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Avoid blocking the front grille with curtains or furniture.
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Schedule an annual AirGreen audit , especially before summer heat waves.
What this case reveals about PTAC systems
PTAC (Packaged Terminal Air Conditioners) units , very common in Montreal, Laval and on the South Shore, are appreciated for their simplicity and efficiency in multi-family buildings, hotels or compact offices . However, they require meticulous maintenance , because:
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Dust and urban pollutants can block coils.
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Temperature sensors and electronic boards are sensitive to power surges.
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A dirty or poorly ventilated compressor can lead to costly breakdown.
This is why AirGreen always recommends an annual professional inspection , especially for appliances from brands like Friedrich, Amana, Gree or Zephyr , which are very common in Montreal's real estate market.
AirGreen expertise: precision and reliability
At AirGreen , our approach is based on three pillars:
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Precise diagnosis , based on electronic and thermodynamic measurements.
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Durable repair , with parts certified by the manufacturer.
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Compliance with HVAC standards in force in Quebec.
Whether it's for a Friedrich PTAC in Côte-des-Neiges , a Fujitsu wall-mounted air conditioner in Laval or a Midea heat pump in Longueuil , we intervene with the same rigor and speed.
A local service throughout Greater Montreal
Our technicians travel daily to the boroughs of Montreal , Laval , Longueuil , as well as the North Shore and the South Shore . Our trucks are equipped with all the necessary equipment to diagnose and repair the majority of breakdowns on site , without unnecessary waiting.
This intervention in Côte-des-Neiges–Notre-Dame-de-Grâce perfectly illustrates our commitment: to repair before replacing , always respecting the customer's comfort and budget.
AirGreen , your trusted HVAC partner for the repair, maintenance and installation of PTAC and heat pump systems in Montreal and throughout the metropolitan area.