A tricky service call: refurbishing a wall unit in the middle of a Montreal winter
At AirGreen , we know that a wall-mounted heat pump is much more than just a device: it's an essential element of home comfort, especially when the cold sets in in Montreal. Our team was recently called to work in Outremont , in a typical Montreal duplex, for a repair on a Fujitsu wall-mounted heat pump with an intermittent operating problem.
Context of the intervention
The client contacted us after noticing that his heat pump was blowing lukewarm air, unable to effectively heat his living room. Despite regular filter cleaning, the indoor unit displayed an error light and shut down on its own after a few minutes of operation. With outdoor temperatures hovering around -10°C, the repair needed to be quick and efficient.
Diagnosis: Control board failure and condensate drain obstruction
Upon arrival, our technician removed the front panel of the Fujitsu wall unit to access the electronics compartment . Upon examining the main control board , he noticed signs of light corrosion caused by moisture buildup around the enclosure. This condensation was coming from a partially blocked condensate drain , a common problem when seasonal maintenance has not been performed before winter.
We then carried out:
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A voltage test to check communication between the main board and the fan motor.
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A continuity test on the cables connecting the temperature sensor and the power board.
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An inspection of the indoor coil , to assess the possible presence of accumulated ice or dust.
The final diagnosis confirmed a double problem:
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Faulty electronic card (poor contact at the motor relay).
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Clogged drain causing excessive moisture near the electrical module.
Steps of repair
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Powering down and securing the workstation : First of all, the device was completely unplugged and isolated.
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Complete cleaning of the condensate tray and drainage pipe using a jet of compressed air and an antibacterial solution.
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Replacement of the Fujitsu control board with an original module compatible with the Halcyon series.
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Checking the electrical connections and the defrost sensor , often used during periods of intense cold.
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Complete system restart and observation of several heating and defrost cycles.
Result: restored comfort and optimal performance
Once the repair was completed, the heat pump resumed stable and quiet operation. Temperatures measured at the unit's outlet reached over 45°C in heating mode , a performance consistent with the manufacturer's specifications.
The customer immediately felt the difference: constant hot air, a discreet unit and standardized power consumption.
AirGreen Technical Analysis and Advice
This intervention clearly illustrates the importance of preventive maintenance for wall-mounted HVAC systems in Montreal. Even a small drain obstruction can cause enough moisture to damage the control board—an expensive part that is vital to the proper functioning of the system.
Here are some recommendations that we systematically share with our clients:
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Clean the internal filters every two months, especially during periods of heavy use.
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Schedule a complete pre-winter service , including checking the drain and refrigerant pressure.
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Maintain clearance around the outdoor unit to allow for optimal defrosting.
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Monitor indicator lights : Recurring flashing is often a warning sign of an electrical problem.
Why trust AirGreen
At AirGreen , every service call is handled with the rigor of a workshop diagnosis. Our certified technicians have all the necessary equipment to intervene quickly, whether it's a Fujitsu, Gree, Midea, Sharp or Zephyr .
We cover Montreal, Laval, Longueuil, the North Shore and the South Shore , with a constant concern for transparency, speed and sustainability in each intervention.
Our goal is simple: to restore your HVAC system to its original efficiency, whatever the season.