Keeping your multizone system performing at its best requires diligent maintenance... but only if you avoid certain critical mistakes.
At AirGreen, specialists in HVAC installation and maintenance across Montreal, Laval, Longueuil, the North Shore and the South Shore, we’re often called in to fix the consequences of poor maintenance habits. In this article, we’re sharing the 7 most common mistakes we see during service calls on multizone heat pumps, along with practical tips to help you maintain peak performance year-round.
Poor maintenance: a silent threat to your multizone system
A multizone system is designed to provide customized thermal comfort across several zones of your home or building. It allows you to control the temperature independently in each room, while optimizing energy consumption. But this advanced technology requires special attention: without proper maintenance, its performance drops, energy use spikes, and its lifespan is drastically reduced.
1. Neglecting to clean the indoor filters
Each indoor wall unit in your zones contains air filters that collect dust, pet hair, pollen, and other particles. These filters should be cleaned monthly, especially during peak usage seasons (summer and winter).
Common mistake: Some homeowners believe the system is fine as long as air is blowing. But clogged filters reduce airflow, force the compressor to work harder, and can lead to overheating.
Our tip: In addition to cleaning the filters, regularly check the air grilles and never block the wall units.
2. Ignoring the outdoor unit (condenser)
In the field, we often find outdoor units obstructed by fallen leaves, snow, or even branches. This prevents proper heat exchange, reduces system efficiency, and can lead to costly breakdowns.
Real example: In Boisbriand, we were recently called in to repair a faulty Gree Sapphire multizone system. The outdoor unit was completely buried in hardened snow. The result: compressor overheating, unit shutdown, and loss of heating throughout the entire floor.
AirGreen tip: Keep at least 60 cm of clearance around the unit, and remove snow or debris after every storm.
3. Skipping professional annual maintenance
Many believe that simply cleaning the filters is enough. However, a multizone heat pump includes complex components (sensors, circuit board, reversing valve, R-32 or R-410A refrigerant) that require a professional technical inspection every year.
During our maintenance visits, we check:
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Refrigerant pressure
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Seal integrity of connections
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Condition of the coils (evaporator and condenser)
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Compressor performance
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Calibration of multizone thermostats
4. Using the wrong operating mode
Multizone systems allow independent heating or cooling modes for each zone. However, running some zones in heating mode while others are in cooling mode creates an internal conflict in the compressor.
Case in Longueuil: A homeowner was frequently switching between cooling in the bedrooms and heating in the living room. After a few weeks, the system experienced a reversing valve failure.
Our recommendation: Coordinate the operating modes between zones, and use the smart automatic mode if available.
5. Ignoring system error messages
Several recent models like the Fujitsu KZAH, Gree Multi21, or Mitsubishi Zuba display error codes or warning lights when something isn’t right. Ignoring these alerts or resetting them without investigating often makes the problem worse.
Important: If an error code persists for more than 24 hours, contact our team. A fast response can prevent damage to the compressor or circuit boards.
6. Using inappropriate cleaning products
Some users apply harsh cleaning agents or use high-pressure water on the indoor units. This can damage the evaporator fins, short-circuit electronic components, or cause mold to develop inside.
At AirGreen, we use manufacturer-approved cleaning products, and apply deep cleaning techniques with low-pressure equipment, ensuring no damage to your units.
7. Failing to check refrigerant levels
A multizone system can appear to function even with a slight refrigerant deficiency, but this significantly reduces its efficiency. If you notice that certain zones struggle to reach the desired temperature, it could be a sign of a leak or undercharge.
Our certified technicians perform pressure tests and, if needed, recharge the system with the correct type of refrigerant (usually R-32, R-410A, or R-454B depending on the model).
Bonus: Our tips to extend the life of your multizone system
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Hire a certified technician once a year, even if everything seems fine.
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Keep a maintenance log, noting cleanings, system alerts, and technician visits.
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Avoid overloading your electrical system: install a dedicated breaker for your multizone heat pump.
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Rely on local experts: At AirGreen, we fully understand the climate conditions in Montreal, Laval, Longueuil, the North Shore and South Shore, and we tailor every maintenance plan to your environment.
AirGreen’s expertise, at your service throughout Greater Montreal
Our preventive maintenance services for multizone systems help our clients extend the life of their units, maximize comfort, and most importantly, reduce electricity bills. Whether you own a Fujitsu, Gree, Mitsubishi, or another system, we adapt our methods to the highest industry standards.
Summary of mistakes to avoid:
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Not cleaning the filters
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Allowing the outdoor unit to get blocked
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Skipping annual professional servicing
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Running opposite heating/cooling modes
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Ignoring system error messages
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Cleaning with improper products
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Neglecting refrigerant levels
AirGreen is a team committed to bringing you the best in HVAC, with tailor-made solutions, rigorous customer service, and top-notch interventions. For any service or inspection of your multizone heat pump, contact us today.