Repair of a Midea MultiZone heat pump in Rosemont–La Petite-Patrie

When winter cold puts rooftop installations to the test

At AirGreen , we know that Montreal winters put a strain on HVAC systems , especially units installed on the flat roofs typical of Rosemont–La Petite-Patrie plexes. This was exactly the context of our last service intervention on a Midea MultiZone heat pump , where the cold and snow had caused a complete breakdown of the heating system.

The context of the call

The customer contacted us urgently one February morning. His Midea heat pump , installed on the roof, had not been blowing hot air since the day before, while the outside temperature was around -18°C. A buildup of snow was partially covering the condenser, preventing the automatic defrost system from functioning properly.

Technical diagnosis in the field

Upon our arrival, our technician observed several revealing signs:

• Accumulation of snow and ice around the outdoor coil;

• Refrigeration cables partially exposed to extreme cold without sufficient protection;

• Blocked drainage , resulting in the formation of an ice layer under the unit;

• An error code related to the outdoor temperature sensor , detected via the Midea control panel.

After turning off the power to make the operation safe, we carefully cleared the snow around the condenser and carried out a resistance test on the sensors . The result: the outdoor sensor showed an inconsistent reading, indicating a malfunction due to prolonged freezing.

Repair and recommissioning steps

1. Complete and safe defrosting of the condenser :
   Using a heat gun on low intensity to remove the ice without damaging the fins.

2. Replacing the outside temperature sensor :
   Installation of an original Midea sensor, calibrated according to the manufacturer's specifications.

3. Re-insulation of refrigeration lines :
   Application of a new UV and frost resistant insulating sheath, ensuring protection of the R-32 refrigerant against thermal losses.

4. Automatic defrosting revision :
   Adjusted the defrost cycle to activate at more frequent intervals during periods of extreme cold.

5. Cleaning the installation area :
   Removing the snow accumulated around the aluminum support and checking the stability of the platform.

Result: comfort restored and reliability increased

A few minutes after restarting, the Midea MultiZone heat pump resumed its normal heating cycle. The interior ducts returned to a stable and constant temperature, and the house gradually warmed up without interruption.

The client was impressed by the speed of the intervention, especially in the middle of winter. We took the opportunity to recommend some good winter maintenance practices :

• Check regularly that snow is not blocking the condenser ;

• Ensure the drain is free of ice ;

• Schedule a preventive inspection in the fall before the big cold weather;

• Maintain a free space of at least 60 cm around the unit for optimal ventilation.

AirGreen expertise: intervening in all conditions

Working on a snowy roof in the middle of a Montreal winter requires technical expertise and meticulous preparation . At AirGreen, we operate in these extreme conditions thanks to our adapted equipment and our in-depth knowledge of HVAC systems from Midea , Sharp, Fujitsu, Gree and several other trusted brands.

Our interventions in urban neighborhoods like Rosemont, Plateau-Mont-Royal, and Ville-Marie often require different logistics: ladder access, narrow roofs, and safe snow removal management. It's this expertise that makes the difference: our technicians are trained to intervene effectively without compromising the safety of the building or equipment.

Preventing winter breakdowns: our recommendations

For building owners in Montreal and on the North Shore and South Shore , here are some essential measures:

• Install a heating cable for condenser drainage;

• Use winter grade insulation protection on refrigeration lines;

• Raise the outdoor unit to avoid contact with accumulated snow;

• Perform a complete pre-winter service including checking the defrost, sensors and refrigerant charge.

A heat pump ready for winter thanks to AirGreen

Thanks to this intervention, the Midea heat pump is working optimally again and is now better protected against harsh weather conditions. The customer can face the winter with peace of mind, with efficient heating and controlled energy consumption .

At AirGreen, we are proud to offer complete HVAC repair services in Montreal, Laval, Longueuil, as well as on the North and South Shores , guaranteeing the reliability, performance and lasting comfort of our installations every time.