When a rooftop heat pump shows signs of weakness
At AirGreen , we regularly work on rooftop HVAC installations in Montreal, particularly in residential and commercial buildings where interior space is limited. This was the case for this service call in Côte-des-Neiges , where a Midea wall-mounted heat pump installed on the roof of a multi-family building had not been working properly for several days. The customer reported a noticeable drop in heating and cooling, accompanied by an abnormal noise coming from the outdoor unit.
Initial inspection: a precise diagnosis on the ground
Upon our arrival, we noticed that the Midea condenser was securely mounted on an aluminum support fixed to treated wooden beams , typical of flat roof installations in Montreal. This type of mounting is often chosen to guarantee good stability while ensuring adequate condensate drainage .
After an initial visual inspection, we noted:
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A clogged coil in the outdoor unit.
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Unusual vibrations when starting the compressor.
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Partially damaged insulation on the refrigeration line.
These factors could explain the loss of performance and excessive noise .
Step 1: Electrical Check and Refrigerant Pressures
We started by testing the power supply and the connections to the nearby wall breaker. The power supply was stable, but the refrigeration pressure readings indicated a slight lack of R-32 refrigerant , suggesting a microleak in the circuit.
Step 2: Find and repair the leak
Using an electronic detector, we located a small leak on the solder of the liquid connection - a common situation on systems subject to significant thermal variations on the roof.
We have :
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Flushed the system.
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Remixed the relevant section to the money.
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Performed a full leak test under nitrogen.
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Pulled a complete vacuum on the circuit.
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Recharged the heat pump with the exact amount of R-32 according to the Midea manufacturer's specifications.
Step 3: Vibration Reduction and Cosmetic Restoration
We also replaced the anti-vibration pads under the compressor and corrected the slightly misaligned aluminum bracket mount . The pipe insulation was redone and carefully protected with white UV-resistant tape , ensuring better durability in Montreal's weather conditions.
Step 4: Final Check and Restored Performance
Once the recharge was completed and the system was back in service, the Midea heat pump resumed normal operation. The measurements showed:
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Balanced pressure.
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Optimal thermal efficiency .
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A total reduction in noise .
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A blowing temperature in accordance with specifications.
The client, who occupies the top floor of the building, immediately noticed a clear difference in interior comfort , especially on hot days.
Why trust your HVAC repairs to AirGreen
Rooftop installations, while convenient for freeing up interior space, require advanced technical expertise . Our technicians are trained to:
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Diagnose and repair all types of wall-mounted or multi-zone heat pumps .
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Working safely on flat roofs and managing systems exposed to the elements .
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Use recharging and soldering procedures that comply with Midea, Gree, Sharp, and Fujitsu standards .
At AirGreen, we provide a transparent and sustainable service, with original parts and performance guarantees on our interventions.
Tips for preventing roof breakdowns
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Clean the coils at least once a year.
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Check the insulation of the refrigeration pipes before winter.
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Avoid branches or debris around the condenser.
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Schedule annual maintenance — a simple preventative inspection can prevent costly repairs.
Result: restored comfort, maximum efficiency
Thanks to our rapid response, this Midea heat pump in Côte-des-Neiges is now operating at full capacity. The outdoor unit is securely mounted, the seal is restored, and the customer once again benefits from a reliable and efficient HVAC system for the seasons to come.
AirGreen – Experts in heat pump and HVAC system repair in Montreal, Laval, Longueuil, North Shore and South Shore.