An AirGreen intervention to restore the performance of a Chigo wall system on the North Shore
At AirGreen , we respond to service calls every day for heating, ventilation and air conditioning (HVAC) systems throughout Montreal , Laval , Longueuil , as well as on the North Shore and the South Shore .
Recently, our team was called upon in the Saint-Laurent district of Montreal for a Chigo wall-mounted heat pump that was no longer producing enough heat in heating mode, despite a running compressor.
Initial diagnosis: defrosting problem and loss of efficiency in heating mode
The customer contacted us after noticing that his outdoor unit often remained covered in ice, even after several defrost cycles.
Upon our arrival, we observed:
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A condenser frosted over nearly 60% of its surface.
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Flashing indicator lights on the indoor module, indicating an interrupted defrost cycle.
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An air temperature blown inside that is too low to ensure comfort.
Our first hypothesis was that the outside temperature sensor was malfunctioning , preventing the system from properly initiating automatic defrost cycles.
Step 1: Complete inspection of probes and wiring
We started by testing the temperature sensors (indoor, outdoor and exchanger) using a digital multimeter.
The external probe displayed an abnormal resistance, not corresponding to the temperature curve provided by the manufacturer Chigo.
We also checked the wiring connecting the indoor unit's main board to the outdoor module—no damaged wires were detected, confirming that the problem was indeed with the sensor.
The defective part was replaced with an original Chigo temperature sensor , calibrated for this specific model of heat pump.
Step 2: Cleaning the condenser and realigning the wall base
Before restarting, we performed a complete cleaning of the condenser to remove residual ice and accumulated debris.
We also noticed that the outdoor unit's wall-mounted base was slightly tilted toward the wall, which could promote water and ice buildup under the coil.
Our technician realigned and tightened the metal supports to ensure adequate drainage of condensate , thus preventing future accumulations.
Step 3: Functional test and calibration of the defrost cycle
Once the sensor was replaced, we restarted the heat pump in heating mode.
The pressures measured on the R-410A refrigeration circuit were stable and in accordance with the manufacturer's specifications.
We then forced a manual defrost cycle via the maintenance remote.
This time, the compressor and reversing valve responded normally, the ice cleared quickly, and the cycle completed automatically—proof that the defrost system was fully functional.
Results and performance restored
After 20 minutes of operation, we measured:
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A blowing temperature of 42°C in heating mode.
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A difference of 24°C between incoming and outgoing air.
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No frost buildup on the outdoor unit after three complete cycles.
The customer was immediately able to notice a significant improvement in interior comfort , as well as a reduction in the operating noise of the Chigo heat pump.
Our recommendations to prevent future problems
At the end of the intervention, our team shared several maintenance tips:
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Check the condition of the outdoor condenser regularly , especially in winter, to look for signs of excessive frost.
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Clean the interior filters every 6 to 8 weeks.
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Have the heat pump inspected at least once a year by an AirGreen certified technician.
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Maintain a minimum clearance of 30 cm around the outdoor unit to ensure good air circulation.
AirGreen: your HVAC expert in Montreal and the North Shore
This intervention in Saint-Laurent once again demonstrates our expertise in repairing wall-mounted heat pumps .
Whether it's Chigo, Gree, Fujitsu, Midea, Sharp or Mitsubishi systems, our team is equipped to quickly diagnose faults, carry out necessary repairs and ensure optimal energy efficiency .
At AirGreen, every intervention is carried out with rigor, transparency and attention to detail — whether you are in Montreal , Laval , Terrebonne , Brossard or Saint-Lambert , you can count on us to ensure the comfort of your home all year round.