Uninterrupted comfort in the heart of downtown
At AirGreen , we frequently work in buildings in downtown Montreal, where PTAC (Packaged Terminal Air Conditioner) systems are very common—especially in modern condos and apartments. This type of unit, integrated directly into the wall, provides both heating and cooling, and must operate continuously throughout the year.
Our team was recently called to an apartment in Ville-Marie for a broken PTAC , unable to produce heat despite the thermostat settings.
Initial diagnosis: total lack of response from the module
The customer noticed that his unit was no longer responding, even after several restart attempts. During our inspection, we found:
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No indicator light on the control panel.
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A supply voltage present at the outlet , confirming that the current was reaching the system.
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An internal resistance detected but inactive , suggesting a fault in the electronic control module .
These observations indicated a failure of the main control board , a relatively common problem on PTAC units installed in heavy-duty urban environments.
In-depth analysis: control board and thermal probes
We removed the front panel of the system to access the electronic board . After checking with a multimeter:
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The 240V input voltage was stable.
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The built-in transformer did provide 24V for the control circuits.
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However, no output was being sent to the fan or heating element.
A visual inspection revealed very slight oxidation on the board and a blackened thermal connector , possibly caused by a power surge or moisture infiltration. The temperature sensors also showed inconsistent values, confirming a general electronic failure.
Intervention: replacement of the control module and complete test
We replaced the complete control board with an original part from the manufacturer, then reconnected all the circuit cables:
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Connecting the air temperature sensor .
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Heating relay calibration .
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Checking the polarity of the fan motor terminals .
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Testing of thermal safety devices and internal fuses .
Once the repair was complete, the PTAC restarted without any anomalies. The interior fan restarted and the heating element quickly reached 46°C at the air outlet. After 15 minutes of observation, the system alternated perfectly between heating and ventilation.
Prevention: tips for extending the life of PTACs
This outage, although resolved, highlights the need for periodic maintenance on PTAC appliances, which are often neglected in condos and buildings in Montreal. We recommend:
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Cleaning of filters and coils every 3 to 6 months.
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Annual check of the control module to prevent oxidation.
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Checking the power cable and internal connections.
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Installing a differential circuit breaker if the building is old, to avoid power surges.
Our technicians also offer customized maintenance plans for condominium associations and property managers to ensure optimal long-term performance.
Result: heat restored and reliability restored
Thanks to a quick and methodical intervention, the client regained the expected comfort as soon as we left. The PTAC system , now stabilized, was operating at full capacity without excess energy consumption. This repair confirms the importance of an accurate diagnosis and specialized expertise in integrated wall systems.
AirGreen: the PTAC systems specialist in Montreal
Whether for PTAC units, wall-mounted heat pumps or central systems , our team operates with the same rigor throughout Greater Montreal , including Laval , the North Shore and the South Shore .
We understand the challenges of urban buildings—space constraints, noise, continuous performance—and tailor each intervention to ensure the sustainability of your HVAC systems.