At AirGreen, we have been installing central heat pumps, complete HVAC systems, and wall-mounted air conditioners throughout Montréal, Laval, Longueuil, the North Shore, and the South Shore for over ten years. In this business, we have noticed a frequently made mistake during the installation of heating and cooling systems: the wrong circuit breaker choice.
This detail, which may seem trivial to some, can have serious consequences: frequent breakdowns, premature equipment wear, safety risks, and even cancellation of the manufacturer’s warranty. Here's why the circuit breaker deserves as much attention as choosing the central heat pump itself.
Real Case: Feedback from a Laval Client After Constant Breaker Trips
A few months ago, we were called in an emergency to Chomedey, Laval, for a client who had had a Gree Flexx 48,000 BTU central heat pump installed by another company. Despite a recent installation, the outdoor unit was constantly tripping the breaker, especially during restarts in heating mode.
After inspecting the system, the diagnosis was immediate: undersized circuit breaker (40 A instead of the required 50 A as per the manufacturer's installation manual). Result: overload during compressor startup, random shutdowns, and premature wear on the power relay.
Our solution: replacing the circuit breaker with a 50 A bipolar breaker with a D curve, recalibrating thermal protections, and validating the grounding. Since then, the system has been running smoothly.
Why Is the Circuit Breaker Choice So Critical in HVAC Systems?
1. Every central heat pump has specific electrical requirements
The manufacturer’s manual always specifies the minimum circuit ampacity (MCA) and the maximum overcurrent protection (MOCP) required. Failing to follow these, it’s compromising both safety and performance.
2. Compressor startup generates a high current surge
Even Inverter models create a starting current spike when first powered on. An incorrectly chosen circuit breaker might treat this spike as an overload and trip unnecessarily, interrupting occupant comfort.
3. An improper circuit breaker voids the manufacturer’s warranty
Leading manufacturers such as Bosch, Gree, Fujitsu, Goodman, or Lennox require that electrical installations comply with their standards. If a failure occurs and the electrical supply doesn’t meet their recommendations, the warranty can be denied.
4. The safety of the occupants is at risk
An incorrectly sized circuit breaker might not properly protect against real overcurrent situations or short circuits. In HVAC systems, where electronic components are sensitive, this protection is vital.
What Does the Québec Electrical Code Say?
The Canadian Electrical Code (CEC), enforced by the Quebec Building Authority (RBQ), mandates that every HVAC installation complies with Sections 28 and 62 regarding load, protection, and grounding.
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Bipolar thermal magnetic circuit breakers are mandatory for 240 V equipment
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Wiring must be sized according to the continuous load (80% of the breaker’s capacity)
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Metallic grounding required for all equipment
Any deviation from these rules can result in non-compliance, or even an inspection notice from Hydro-Québec or a municipal inspector.
Our Recommendations at AirGreen
1. Always read the manufacturer’s installation manual carefully
Before every installation, we consult the detailed technical sections of the manual, especially:
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MCA (minimum required ampacity)
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MOCP (maximum allowed overcurrent protection)
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Type of breaker (standard, curve D, curve C, etc.)
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Compressor startup data (LRA)
2. Choose a circuit breaker compatible with the startup profile
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Curve D for direct-start compressors
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Curve C for progressive start or Inverter systems
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Differential breaker recommended in newly built residential homes
3. Check the wire gauge and connector size
Installing a 50 A breaker on a #10 AWG wire is a dangerous mistake. The wire must be sized according to the expected current.
4. Work with a master electrician in collaboration with the HVAC team
At AirGreen, every central heat pump installation is carried out in partnership with a certified electrician, who ensures that every critical electrical point is validated before the system is powered on.
Other Electrical Interventions by AirGreen
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Longueuil: Replaced a 30 A breaker with a 40 A for a Fujitsu KZAH wall-mounted heat pump powered at 220 V.
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Terrebonne: Installed a 60 A curve D breaker on a Bosch IDS Light system.
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Boucherville: Corrected an undersized wiring between the main panel and the outdoor unit.
What Our Clients Appreciate
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No more random trips
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Smoother and quieter systems
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Improved energy efficiency
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Full compliance with Hydro-Québec and CEC standards
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No surprises with warranty claims
Conclusion: The choice of circuit breaker is not a trivial detail. It’s a fundamental element of your HVAC installation that affects safety, performance, longevity, and even warranty validity for your central heat pump. At AirGreen, we never install a system without carefully validating every electrical parameter. This attention to detail makes all the difference on the ground.
Need a quote? Our team is here to assist you every step of the way, from model selection to compliant electrical commissioning, serving Montréal, Laval, Longueuil, the North Shore, and the South Shore.