Intervention on a wall-mounted heat pump that no longer started after a power outage
A client in the Mercier–Hochelaga-Maisonneuve neighborhood of Montreal recently contacted us for a service call regarding a Gree wall-mounted heat pump installed on the back wall of his red brick home. After a local power outage during a storm , the outdoor unit would not restart, leaving the home without heating or cooling.
At AirGreen , we often intervene in this type of situation, particularly with modern electronic systems which include control boards sensitive to voltage variations.
Initial inspection and safety check
Before any work, our technicians checked the power supply voltage at the dedicated circuit breaker and the external electrical box. Power was present, but there was no signal coming from the compressor's main board.
A quick visual inspection revealed no apparent signs of burning or oxidation , but we still removed the cover to perform a more thorough diagnosis using our Fluke professional multimeter .
Problem diagnosis: defective electronic card
Measurements showed that voltage was reaching the control board , but the board was not relaying the signal to the inverter compressor . This type of failure often occurs after a power surge, especially when the system is not protected by a surge protector .
We also tested the starter relay and the control capacitor , two components often involved in this type of failure. The values were in line with the manufacturer's specifications, confirming that the main electronic board (PCB) was the cause of the problem .
Card replacement and recommissioning
After informing the customer and obtaining their approval, we ordered and installed a replacement Gree motherboard compatible with their wall-mounted heat pump model. The work required a complete reconnection of the connectors , respecting the original color coding and electrical safety instructions.
Before switching back on, we checked:
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continuity of grounding ,
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the value of the static pressures of the refrigeration circuit ,
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and the freedom of external conduits to avoid any obstruction.
Once the new board was installed, we restored power and observed an immediate start of the outdoor fan followed by the start of the compressor.
After 10 minutes of operation, the system displayed:
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Low pressure: 120 psi
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High pressure: 390 psi
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Indoor blowing temperature: 21°C (in air conditioning mode)
Values perfectly in line with a Gree system in summer.
Results and customer satisfaction
The customer immediately felt a return to normal coolness inside, with a constant and quiet airflow. We recommended adding a surge protector to the power circuit to prevent a future power surge from further damaging the unit's electronics.
Our team also explained good maintenance practices to preserve the longevity of the system:
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Turn off the heat pump using the remote control before any prolonged power outage.
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Clean the internal filters every month during the usage season.
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Have electrical connections and pressures checked once a year.
AirGreen expertise in diagnosing electronic faults
Gree Eco Inverter systems are efficient, but require rigorous maintenance and accurate diagnostics in the event of a breakdown. Our certified technicians are trained to work on all major brands of wall-mounted heat pumps in Montreal, Laval, Longueuil, as well as on the North and South Shores.
This type of intervention demonstrates the importance of a methodical and safe analysis , because replacing a card without checking the underlying electrical causes could cause the fault to reproduce.
At AirGreen, we always apply a three-step approach:
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Precise and documented diagnosis .
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Durable repair with certified parts.
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Personalized advice to avoid recurrence.
Why Montreal residents trust AirGreen
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Qualified technicians in residential and commercial HVAC systems.
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Fast and localized service throughout all neighborhoods of Montreal.
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Original parts and guaranteed repairs.
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Complete transparency on costs and interventions.
Thanks to this rigorous approach, the Gree heat pump of the Mercier–Hochelaga-Maisonneuve client has regained its full performance, ensuring constant comfort and optimal energy efficiency .