Technical intervention on the roof of a West Island residence
At AirGreen , we recently completed a complete repair of a Gree Ultra Heat MultiZone heat pump on the flat roof of a modern home in Beaconsfield , in Montreal's West Island. This high-capacity unit, from the GMV Ultra Heat series, is designed to deliver exceptional performance even in the harshest Quebec winters. However, despite its proven reliability, it required urgent intervention after a loss of performance was reported by the customer.
Symptoms observed: loss of power and abnormal defrost cycle
The owner has noticed a significant drop in heating in the rooms served by the MultiZone system over the past few weeks, accompanied by overly frequent defrost cycles . This unusual behavior is often a sign of a pressure imbalance in the refrigeration circuit or a faulty sensor.
Our AirGreen team therefore went on site to conduct a thorough inspection of this Gree Ultra Heat heat pump — a unit equipped with two vertical fans and a high-performance inverter compressor , ideal for multi-story residences.
Detailed diagnosis carried out on the roof
With the outdoor unit installed on a treated wooden base , raised to protect it from frost and water accumulation, our technicians first checked the mechanical stability and integrity of the base.
The following observations were noted:
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Accumulation of dust and pollen on the surface of the evaporator, limiting heat exchange.
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Frosted temperature sensor , distorting the reading of actual conditions and triggering untimely defrosting.
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Refrigerant pressure slightly lower than Gree recommended standard (verified via digital manifold and Bluetooth probe).
The diagnosis therefore confirmed that the combination of a defective sensor and a microleak was responsible for the loss of efficiency of the system.
AirGreen Repair Process
Our intervention took place in several methodical stages, guaranteeing a complete and lasting return to service:
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Partial disassembly of the side panel to access the sensor module.
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Replacement of the evaporator temperature sensor with an original Gree part.
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Inspection of flare fittings using an electronic leak detector (Sniffer R-410A type).
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Tightening and resealing of the defective connection at the compressor outlet.
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Calibrated recharge of R-410A refrigerant , according to the manufacturer's specifications.
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Complete cleaning of coils and ventilation grilles.
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Complete test of the defrost cycle and measurement of the internal blowing temperatures.
Each step was validated using an HVAC performance analyzer , ensuring that the heat pump again met the energy efficiency standards (SEER/HSPF) of the Ultra Heat range.
Results obtained after intervention
Upon restart, the system's behavior returned to normal. We observed:
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A quick return to stable heating mode , without excessive interruption.
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Uniform blowing temperatures in all interior areas.
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A significant reduction in compressor operating noise .
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Power consumption returned to compliance with the technical data sheet.
The client noticed an immediate improvement in thermal comfort and a significant reduction in temperature fluctuations between rooms.
Maintenance tips for a heat pump on a flat roof
A heat pump installed on a flat roof , like this one in Beaconsfield, requires special attention to maintain its long-term performance. At AirGreen, we systematically recommend to our clients:
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Have the refrigerant charge and pressures checked at least once a year.
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Clean the coils in spring and fall to ensure optimal air circulation.
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To inspect the stability of the support after freeze and thaw cycles.
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To avoid any accumulation of snow or water around the base in winter.
Regular maintenance helps prevent overconsumption of energy, extends the life of the compressor, and maintains indoor comfort, even at -25°C.
AirGreen expertise: precision service in Montreal and on the North Shore
The intervention on this Gree Ultra Heat illustrates the technical rigor and precision of our teams. At AirGreen , we intervene every week in Montreal, Laval, Longueuil , as well as on the North Shore and the South Shore , to diagnose and repair all types of HVAC systems : wall-mounted heat pumps, MultiZone, central, ducted or VRF .
Our technicians are trained on Gree, Fujitsu, Mitsubishi, Midea, Bosch and Goodman technologies , and have advanced diagnostic equipment to ensure fast and lasting repairs.
Each intervention is documented, measured and accompanied by precise recommendations to optimize performance and energy consumption.
AirGreen, your trusted HVAC partner in Beaconsfield
Thanks to our expertise and our in-depth understanding of the Montreal climate , we guarantee our customers reliable repairs , durable installations and personalized follow-up . Whether your system is rooftop, wall-mounted or centralized, we have the tools, skills and certifications necessary to restore it to perfect working order.
Trust AirGreen for your heat pump repair, maintenance and optimization needs in Beaconsfield and throughout the greater metropolitan area.