A Preventable Installation Mistake That Cost Thousands: A Critical AirGreen Intervention
In the world of residential and commercial HVAC, small details can lead to major consequences. Across Montréal, Laval, Longueuil, the North Shore, and the South Shore, our team often encounters poorly planned installations where high-performance equipment ends up failing prematurely. The story we share here is about a client in Boisbriand, who had to replace their Bosch BOVA36HDN1M20G central heat pump barely two years after installation — the cause: an improperly sloped drain.
Context of the Original Installation and the Problem Encountered
Technical Details of the Central Heat Pump
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Model: Bosch BOVA36HDN1M20G
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Capacity: 36,000 BTU (3 tons)
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Technology: Inverter, SEER 20 / HSPF 10.5
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Refrigerant: R-410A
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Property Type: 1200 sq. ft. bungalow in Boisbriand
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Installation: done by a competing company in May 2022
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LogisVert Grant Received: $5,295
Symptoms Observed After 18 Months
By winter 2023:
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Ice formation beneath the outdoor unit
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Frequent shutdowns in heating mode
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Unusual noises coming from the compressor
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Sharp increase in electricity bills
AirGreen’s Complete Diagnosis
During our visit in October 2024, our technicians quickly identified the root cause: the defrost drain pipe was sloped in the wrong direction. The result:
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Defrost water failed to drain, accumulating beneath the unit
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Water froze rapidly, blocking the fan
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Ineffective defrost cycles overheated the compressor
Solutions Implemented by AirGreen
Step 1: Removal of the Original Unit
The original heat pump was beyond saving. We proceeded with a full removal, carefully disconnecting the electrical wiring, refrigerant lines, and support mounts.
Step 2: Complete System Redesign
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New Heat Pump Installed: Fujitsu AOUA36RLXFZ
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Capacity: 36,000 BTU (central multi-zone)
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Mounting: elevated base with frost-resistant anchoring
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Drainage: redesigned with a 2% downward slope + heated drain line
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Defrost cycles reprogrammed for local winter conditions
Step 3: Performance Testing
After installation, we performed:
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Simulated defrost tests
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Drainage flow verification
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Heating performance testing at -15°C
Result: no more ice buildup, stable operation, and a very relieved client.
What This Story Teaches Us
HVAC Installation Is More Than Just Mounting a Unit
The performance of a central heat pump depends on every component being perfectly integrated:
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The slope of the defrost drain
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The orientation of the outdoor unit
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The elevation level
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Proper airflow and drainage management
The Importance of Installer Training
At AirGreen, all our technicians are specifically trained for Québec’s climate conditions. We teach:
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Minimum drain slope standards: 1.5% to 2%
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The importance of keeping drainage away from the foundation
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Risks associated with defrost cycles that are too frequent — or nonexistent
Practical Advice to Avoid This Kind of Problem
Do:
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Request a complete site assessment before installation
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Make sure there’s an active, well-sloped drainage system
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Prioritize units with strong cold-climate performance (NEEP listed)
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Schedule a system inspection before each winter
Don’t:
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Install a heat pump on an undrained surface
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Use drain pipes that are too short or rigid
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Skip annual heat pump maintenance
Customer Testimonial: “If only I had known…”
“I lost over $9,000 with that first installation. I thought all HVAC companies were the same… clearly not. AirGreen was professional, fast, and most importantly, they took the time to explain the technical details. This time, I actually feel confident.”
— AirGreen client in Boisbriand
Why Choose AirGreen for Your HVAC Installation?
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Over 15 years of experience installing central heat pumps
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Projects that are 100% compliant with LogisVert and Chauffez Vert grants
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Certified technicians supervised by experienced specialists
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Full parts and labor warranty
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Local, responsive after-sales service throughout Montréal, Laval, Longueuil, the North Shore, and the South Shore
Conclusion: A Simple Drain Error Can Be Costly
This failed installation in Boisbriand is a reminder that even the best HVAC system can be ruined by a single technical oversight. Thanks to our rigorous process, AirGreen guarantees installations that are durable, efficient, and protected against avoidable errors. Don’t let a poor drain slope compromise your comfort.