A suspended air exchanger, worn flexible ducts, and residential ventilation needing to be rebalanced
In Sainte-Catherine, on the South Shore, our AirGreen team responded to a service call for an Aston air exchanger installed in the basement, suspended by chains between wooden joists and connected to a network of flexible ducts. As soon as the mechanical ceiling was opened, the context was clear: the device was operating in a typical environment of many Quebec homes, with limited space, insulated ducts, aging sealing tape, limited access to connections, and a ventilation network that visibly needed reorganization.
The client contacted us because the indoor air quality was no longer consistent. Some rooms seemed more humid, the air became heavy after several hours, and the air exchanger produced a noise different from its usual operation. The system did not seem completely stopped, but it no longer properly fulfilled its role: renewing the air, removing moisture, and maintaining healthy circulation in the house.
In a residence in Sainte-Catherine, an air exchanger is especially important in winter and summer. When windows remain closed, indoor air can quickly accumulate moisture, odors, CO₂, fine dust, and household contaminants. A well-maintained Aston device allows this air to be renewed without unnecessarily losing all the energy invested in heating or air conditioning. But when a duct leaks, a filter is saturated, a motor weakens, or the recovery core is clogged, performance quickly drops.
An Aston device installed in a common configuration, but sensitive to details
The observed equipment was a residential Aston air exchanger, with a white metal casing, suspended from the ceiling and connected to several insulated flexible ducts. The exact model was not readable on the front during the visual inspection, but the configuration matched a residential ventilation unit of the VRC or VRE type, depending on the installed version. In both cases, the principle is similar: the device extracts stale air from the house and introduces fresh outdoor air, while limiting energy loss through an exchange core.
The installation showed several elements to check:
- Flexible ducts connected to the device collars;
- Aging sealing tapes around joints;
- Device suspended by chains;
- Proximity to piping and other mechanical elements;
- Tight access to service panels;
- Possibly unbalanced ventilation network;
- Duct insulation to be validated;
- Wall control and power supply to be tested.
This type of installation is common in Sainte-Catherine, Longueuil, Brossard, Candiac, La Prairie, and several areas of the South Shore. It is also found in Montreal, Laval, and on the North Shore, especially in houses where the air exchanger was added after the initial construction or modified during renovations.
Symptoms reported by the customer
The customer was not talking about a total breakdown but a gradual performance drop. This is often the case with air exchangers: the device continues to make noise, sometimes even runs, but the indoor air is no longer renewed effectively.
The main symptoms were as follows:
Indoor humidity harder to control
The customer noticed a feeling of humid air, especially after showers, cooking, or periods when the house remained closed. A well-functioning air exchanger helps remove this moisture. When the extraction flow decreases, humidity remains trapped inside the house.
Unusual noise in the system
A louder, duller, or more vibrating noise can come from a dirty motor, an unbalanced fan, a poorly secured duct, or a suspended device transmitting vibrations to the structure. In the picture, the chain suspension and flexible ducts around the device made this check essential.
Insufficient airflow at the vents
The customer felt that some vents were drawing less air than before. This symptom can be caused by clogged filters, a dirty core, a weakened motor, a crushed duct, or an air leak in the ducts.
Indoor air less fresh
When air exchange is not done properly, occupants quickly notice it: persistent odors, heavy air, condensation on some surfaces, and general discomfort despite functional heating or air conditioning.
Our HVAC diagnosis on the Aston air exchanger
At AirGreen, a service call on an air exchanger is not limited to checking if the unit is on. Balanced ventilation depends on several elements: the unit, filters, core, motors, ducts, grilles, dampers, condensation drain, wall control, and network tightness.
Inspection of the unit and its access
We first checked the general condition of the Aston casing, its suspension, alignment, and access to the panels. A suspended unit must remain stable. If the chains are poorly tensioned, if the unit tilts, or if a duct pulls on one side of the casing, vibrations can appear and the connections can deteriorate.
The work environment was tight, with piping and ducts around the unit. This context requires careful intervention to avoid damaging existing connections or creating new air leaks.
Filter and exchange core inspection
The filters were inspected because they are often the primary cause of airflow loss. Saturated filters block air, strain the motors, and reduce the efficiency of air renewal. In an air exchanger, the filters also protect the recovery core. When neglected for too long, dust reaches the core and makes cleaning more complex.
The core was then checked. A dirty core can reduce heat transfer and slow air circulation. In a well-insulated house, this drop in efficiency is quickly noticed by less consistent ventilation.
Inspection of motors and fans
An air exchanger generally has two circuits: one for stale air expelled outside and one for fresh air introduced into the house. Each circuit depends on a fan. If one of the two motors weakens, the system becomes unbalanced. The house can then be under negative or positive pressure, which can cause cold air infiltration, odors, condensation, or discomfort.
We checked the startup, noise, rotation, vibrations, and stability of the fans. A motor that is still running can still lose performance if the blades are dirty or if the bearings start to wear out.
Flexible duct inspection
The photo shows several flexible ducts around the device, with insulated sections and tape-sealed connections. This point was central to our diagnosis. Flexible ducts are convenient, but they can lose a lot of efficiency when they are:
- Crushed;
- Too bent;
- Poorly attached;
- Partially disconnected;
- Poorly insulated;
- Sealed with aging tape;
- Too long for the required airflow.
A crushed duct can greatly reduce airflow. A poorly sealed connection can send air into the ceiling instead of the rooms. A poorly insulated exterior duct can cause condensation and promote moisture around the device.
Condensation drain inspection
Depending on the type of air exchanger and operating conditions, condensation can form and must be properly drained. A partially blocked drain can cause water inside the unit, odors, corrosion, and sometimes damage to the ceiling or surfaces around the device.
We therefore checked the condition of the drain, its flow, and positioning. In several homes on the South Shore, air exchangers are installed in basements where drainage is sometimes altered after renovations. This check prevents hidden moisture problems.
Identified cause: reduced airflow due to clogging and losses in the ducts
The diagnosis identified a combination of factors. The Aston air exchanger was not simply “dead” or to be replaced. The problem mainly came from a loss of performance caused by internal clogging and duct connections needing repair.
The most important elements were:
- Clogged filters;
- Exchange core requiring cleaning;
- Flexible ducts to be repositioned and better sealed;
- Vibrations to be reduced at the suspension level;
- Drain and flow to be checked;
- Airflow to be rebalanced after intervention.
This type of situation is very common. An air exchanger can operate for years without full maintenance, then gradually lose its capacity. The client then experiences a drop in air quality but does not immediately see the cause, as the device is often hidden in the basement or a mechanical ceiling.
Cleaning, restoration, and advice to maintain good indoor air quality
After the diagnosis, our team proceeded to restore the Aston air exchanger. The goal was clear: to restore airflow, reduce losses, improve air quality, and extend the device's lifespan.
Filter cleaning and replacement as needed
Filters were cleaned or replaced depending on their condition. For an air exchanger, this step is essential. Overly dirty filters strain the motors, reduce airflow, and can give the impression of a more serious malfunction.
We explained to the client that regular filter maintenance must be adapted to the actual use of the house. In a residence with pets, renovation work, dust, heavy occupancy, or proximity to a busy road, filters can clog faster.
Cleaning the heat recovery core
The core was removed and cleaned according to the recommendations applicable to the device type. This step requires caution, as a core can be fragile. Overly aggressive cleaning can damage exchange surfaces, while incomplete cleaning leaves contaminants in place.
Once the core was put back in place, the device could transfer energy more efficiently between outgoing and incoming air. Air renewal then becomes more stable and less energy-consuming.
Repositioning and sealing of ducts
We corrected duct sections that hindered airflow and reinforced the sealing of accessible joints. In a ventilation system, a small leak may seem minor, but several small leaks around the device can significantly reduce the actual amount of air distributed or exhausted.
The fixes allowed us to:
- reduce air leaks;
- improve airflow stability;
- limit vibrations;
- prevent humid air from spreading into the ceiling;
- improve the overall efficiency of the air exchanger.
Checking the wall control and operating modes
We tested the device’s response to available controls: off, low speed, high speed, and timed cycles when present. Many clients use their air exchanger without knowing the exact modes. Poor configuration can lead to either insufficient ventilation or over-ventilation that dries the air and increases heating costs.
We therefore adjusted the recommended usage according to the house’s needs: moderate continuous ventilation, high speed during showers or cooking, and monitoring of indoor humidity levels.
Result: fresher air, restored airflow, and quieter operation
After the intervention, the Aston air exchanger operated more stably. The airflow was better distributed, vibrations were reduced, and the client could use the system with confidence again. The house regained healthier ventilation, with better moisture removal and a fresher air feeling.
This result shows that a service call for an air exchanger can have a direct impact on daily comfort. Even if the unit doesn’t heat or cool like a heat pump, it plays a fundamental role in the home’s HVAC balance.
Mistakes to avoid with an air exchanger
Never cleaning the filters
Dirty filters are one of the most common causes of performance loss. They must be checked regularly.
Ignoring flexible ducts
A crushed or poorly sealed duct can negate part of the unit’s work. The duct network is as important as the unit itself.
Leaving the drain unchecked
A blocked drain can cause humidity, odors, and water damage. It must be inspected during maintenance.
Turning off the unit for long periods
In a sealed home, completely stopping the air exchanger can harm indoor air quality and promote humidity.
Confusing normal noise with problematic vibration
An air exchanger produces some ventilation noise, but new vibrations, rumbling, or clicking should be checked.
Why AirGreen works on air exchangers in Sainte-Catherine
At AirGreen, we repair and maintain Aston air exchangers and many other brands in Greater Montreal. Our approach considers the entire system: unit, ducts, airflow, filters, core, drainage, controls, and the real comfort of occupants.
We serve Sainte-Catherine, Montreal, Laval, Longueuil, the North Shore, and the South Shore for residential HVAC services, including wall-mounted heat pumps, central heat pumps, furnaces, air conditioners, humidifiers, dehumidifiers, and ventilation systems.
A well-maintained air exchanger contributes to a healthier home, better humidity control, and overall improved comfort. This service in Sainte-Catherine highlights the importance of a thorough diagnosis: sometimes, the solution is not replacement but a methodical restoration that restores the system’s full functionality.