Repair of a Gree wall-mounted heat pump in the Old Port of Montreal

AirGreen intervention in an industrial loft

At AirGreen , we're often called upon to work in unusual spaces in downtown Montreal. This was recently the case in a loft in the Old Port , a stunning space with exposed brick walls and wood beams, where the client's Gree wall-mounted heat pump had stopped producing cold air at the most inopportune moment—on the eve of a heat wave.

A unique context: ancient architecture, modern system

The installation, mounted more than three meters high on a brick wall, serves an open-concept space combining a kitchen, living room, and office area. This type of environment, with very high ceilings and large windows, puts a strain on wall-mounted HVAC systems : heat builds up quickly, and temperature fluctuations place significant demands on the compressor and control board.

The customer had noticed for several days a slowdown in the air flow followed by a complete shutdown of the system .

On-site diagnosis: localized electronic fault

Our certified technicians first checked the essential points:

• Stable power supply from the circuit breaker.

• Intact communication between the indoor unit and the Gree outdoor compressor.

• No error message displayed on the remote control.

However, a closer inspection revealed a faulty control board in the indoor unit. This component, exposed to the humidity of the old building, showed signs of oxidation on the main connector.

Using our Gree brand specific diagnostic tools, we confirmed a temperature sensor signal error , preventing the compressor from starting.

Repair and recommissioning

Our team took the following steps:

1. Complete disassembly of the front panel and removal of the electronic card.

2. Thorough cleaning of the connectors and replacement of the main control module with an original Gree part.

3. Recalibrating the indoor temperature sensor via service mode.

4. Pressure test to ensure proper operation of the external compressor.

Once everything was reassembled, the heat pump restarted immediately. We measured a temperature difference of 11°C between the intake air and the blown air , indicating optimal performance.

Advice given to the client

To prevent future outages, we recommended:

• Monthly filter cleaning , essential in a dusty urban environment.

• A complete annual inspection before the summer season, particularly for systems installed in historic buildings.

• The addition of a surge protector to stabilize the often erratic electrical current in the old buildings of Old Montreal.

Result: comfort and efficiency restored

A few hours after our intervention, the client was once again enjoying stable and quiet cooling throughout the loft. The refurbished Gree heat pump now operates with efficiency comparable to that of a new unit.

At AirGreen , our goal is not just to repair, but to extend the useful life of each HVAC system through precise, preventative interventions adapted to the customer's environment .