A targeted intervention to ensure comfort, efficiency and long-term reliability
At AirGreen , we know that rigorous preventative maintenance is key to ensuring the performance, durability, and compliance of commercial HVAC systems. In Laval, we recently completed the full maintenance of a rooftop unit serving a three-story office building housing several technology companies. This York brand unit provides heating, cooling, and ventilation for the entire building.
Context and challenges
The rooftop unit, installed on the building's flat roof, had been operating for several years without thorough maintenance. The building manager contacted us after noticing:
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Significant temperature fluctuations between areas;
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A significant increase in energy consumption ;
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Noise levels higher than normal ;
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And above all, there were smells of stagnant air in certain sections of the building.
The objective of the mandate was clear: to restore optimal system performance while preventing winter breakdowns and extending the lifespan of the equipment .
Initial diagnosis and findings
Before any intervention, our technical team carried out the following:
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A complete record of air flow rates and static pressures;
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A thermographic analysis to detect areas of electrical overheating;
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A check of the BMS (building automation) control parameters ;
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And a detailed visual inspection of the internal components.
Our findings:
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The air filters were heavily clogged , limiting the flow of fresh air;
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The fan belts showed signs of advanced wear;
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The evaporator and condenser coils were clogged, reducing heat transfer;
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An accumulation of stagnant water in the condensate tray indicated a partially blocked drain .
Technical solution implemented
To restore the rooftop unit's performance, AirGreen implemented a comprehensive preventative maintenance procedure , compliant with ASHRAE 62.1 and CSA B52 standards. The main steps included:
1. Thorough cleaning
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Removal of access panels for complete cleaning of coils with a gentle jet and biodegradable solution;
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Vacuuming and washing the filter compartment ;
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Cleaning the condensate drain and disinfecting the collection tray to prevent bacterial growth.
2. Mechanical Maintenance
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Replacement of blower belts and precise tensioning ;
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Lubrication of engine bearings according to manufacturer's specifications;
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Checking the tightness of electrical connections.
3. Checking the refrigeration circuit
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Measurement of operating pressures ;
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Control of overheating and subcooling ;
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Visual inspection of welds and fittings to prevent any refrigerant leaks.
4. Calibration and performance testing
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Programmable thermostat and BMS control adjustment to optimize the operating sequence;
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Air supply and return temperature test ;
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Balancing the airflow to ensure uniform air distribution across the three floors.
Construction site procedures and safety
The intervention took place in the evening to minimize the impact on the occupants . AirGreen technicians implemented a complete lockout/tagout plan , with a secured perimeter and signage compliant with CNESST standards.
Roof access was achieved via an escalator with safety harness, in accordance with Laval municipal regulations and CSA Z259 requirements.
Results and performance indicators
The results obtained after the interview were measurable from the very first days:
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Airflow restored to 98% of nominal capacity ;
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17% reduction in monthly energy consumption ;
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Stabilization of the indoor temperature to ±1.5 °C across all zones;
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Significant improvement in indoor air quality (IAQ) thanks to better filtration;
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A 4 dB reduction in noise level provides improved acoustic comfort.
Continuous maintenance and monitoring of building management systems (BMS)
To maintain this performance, the customer has subscribed to an annual AirGreen maintenance contract , which includes:
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Two preventative visits per year (spring/autumn) ;
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Remote monitoring via the BMS to detect any performance anomalies;
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24/7 availability in case of emergency;
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And a detailed compliance report after each visit.
This program allows the building manager to ensure continuity of operations , while reducing corrective maintenance costs.
Compliance and sustainability
All interventions were carried out in compliance with ASHRAE, CSA and RBQ standards , including:
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ASHRAE 62.1 (Indoor Air Quality);
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ASHRAE 90.1 (Energy Efficiency);
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CSA B52 (Mechanical Refrigeration Systems);
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Regulations respecting the safety of pressure vessels in Quebec .
In addition, the cleaning products used are biodegradable and certified ecological , aligned with the client's environmental policy.
Return on investment and added value
The cost of comprehensive preventative maintenance represents less than 3% of the total cost of premature rooftop replacement . In this specific case, the investment generated:
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An estimated return on investment of 9 months ;
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An 80% reduction in emergency service calls ;
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And an extension of the estimated lifespan of the equipment from 4 to 6 years .
Thanks to this intervention, the client now benefits from a reliable, economical and compliant system, with optimal indoor comfort for its tenants.
AirGreen: Your commercial HVAC partner in Greater Montreal
For over 10 years, AirGreen has been supporting building owners and managers in Montreal, Laval, Longueuil, the North Shore and the South Shore , by offering turnkey commercial HVAC solutions — from design-build to 24/7 preventive maintenance .
Our expertise covers all sectors: offices, institutions, retail, hotels, industries and municipal buildings .
Trust AirGreen to ensure the continued performance of your facilities and maximize your energy efficiency .