A breakdown on a flat roof: expertise and precision from AirGreen
Montreal's flat roofs often present unique challenges for HVAC system maintenance. Recently, our AirGreen team responded to a Midea wall-mounted heat pump installed on the roof of a residential building in the Hochelaga-Maisonneuve neighborhood. The client, a rental property owner, had noticed that the system was no longer producing cooling despite the compressor making apparent operating noise.
A typical Montreal building environment
The Midea heat pump, a compact model from the R-32 Inverter range , was mounted on a raised metal structure, typical of flat roof installations. Directly exposed to the elements and urban dust, this configuration requires increased vigilance, particularly in terms of preventative maintenance.
When our technician arrived, the first step was to turn off the main power and open the side panel of the outdoor unit. A visual inspection immediately revealed two critical points:
-
A buildup of debris and dust on the evaporator fins.
-
Discoloration on the control box , a sign of possible electronic overheating.
Step 1 – Thorough fault diagnosis
We undertook a complete analysis of the electrical circuit and control board. Using a professional multimeter, our technician confirmed unstable voltage to the compressor , caused by a partially burned-out power board .
This failure was caused by poorly insulated power wiring which, due to thermal cycling and humidity, eventually caused water to infiltrate the enclosure.
Step 2 – Control Circuit Replacement and Protection
Once the cause is identified, we have:
-
Removed the faulty electronic card , replaced with an original Midea part.
-
Applied a protective resin to the new welds to prevent any corrosion.
-
Realigned and secured electrical conduits inside a waterproof, CSA-compliant enclosure.
-
Checked the continuity of the wires connecting the indoor and outdoor unit.
This meticulous work made it possible to eliminate the breakdown at its source while ensuring better resistance to external conditions .
Step 3 – Complete cleaning and return to service
Before restarting the heat pump, we performed a thorough cleaning of the condenser using a biodegradable product designed for HVAC systems. This cleaning is essential for:
-
Optimize heat exchange.
-
Reduce energy consumption.
-
Extend the life of the compressor.
Once the maintenance was complete, we performed a comprehensive performance test : refrigerant pressure, evaporation temperature, and compressor amperage. The result: the system was operating at full capacity, with stable and quiet performance.
Step 4 – Personalized advice for long-lasting maintenance
The owner, anxious to avoid future breakdowns, received from us an annual maintenance plan adapted to installations on flat roofs:
-
Check wiring and electrical connections at each change of season.
-
Semi-annual cleaning of the condenser fins.
-
Installation of UV protection on electrical conduits exposed to the sun.
-
Regular monitoring of R-32 refrigerant pressure.
We also suggested adding an HVAC line surge protector to protect the new circuit board from surges common in urban areas.
Another example of AirGreen expertise in Montreal
Thanks to this quick and methodical intervention, the client's Midea heat pump has regained its full performance, ensuring the comfort of the occupants once again. At AirGreen , we make it a point of honor to offer sustainable solutions that comply with the highest HVAC standards , whether for flat roof repairs in Montreal or residential installations in the suburbs.
We operate throughout Montreal , Laval , Longueuil , on the North Shore and the South Shore , to offer fast, rigorous and transparent HVAC repair, maintenance and installation services.