A delicate intervention in an underground garage for a suspended compressor
At AirGreen , we often work in atypical installation contexts. This case in Lachine , in a residential building with indoor parking, illustrates the technical challenges that can arise from wall-mounted heat pumps installed high up , under a concrete slab, in an environment with limited ventilation.
The client, a co-owner of the building, contacted us after noticing that his Fujitsu wall-mounted heat pump had stopped producing heat, with a metallic vibrating noise coming from the outdoor unit suspended from the garage ceiling. The unit, identified as number C-206 , had been installed for approximately 6 years.
Diagnosis: Vibrations, Fan Wear and Drainage Problem
The installation was visually neat, with suspension on threaded rods and insulation of the refrigeration lines. However, the conditions of a cold and damp underground garage can accelerate certain wear phenomena.
Our technicians undertook a complete analysis of the compressor and the refrigeration circuit :
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Mechanical Inspection : The fan had a minor imbalance , causing intermittent rubbing against the protective grille.
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R410A refrigerant pressure measurement : slightly lower than standard, indicating slow loss.
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Electrical test : The starter relay showed abnormal resistance, causing erratic starts.
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Condensate flow : A partial ice plug had formed inside the insulated pipe, restricting drainage.
Repair steps: efficiency and safety
1. Stabilization of the suspended unit
Before any work began, our team secured the Fujitsu heat pump with an AirGreen maintenance harness to prevent any stress on the suspension rods. This allowed for safe work in the confined garage space.
2. Fan Replacement and Realignment
The fan motor , which was slightly misaligned, was removed and replaced with an original Fujitsu compatible model. We also realigned the protective grille to eliminate any metal vibration.
3. Defrosting and cleaning the drainage circuit
The condensate pipe was purged using a stream of warm compressed air. The insulation was then repositioned to prevent future blockages due to freezing.
4. Leak test and recharge of the refrigeration circuit
A nitrogen pressure test confirmed a microleak at a brazed connection. The brazing was reworked, followed by a calibrated recharge with R410A . The pressure stabilized at 118 psi at rest and 380 psi during operation.
5. Replacing the control relay
The compressor start relay has been replaced with a latest generation Fujitsu module, ensuring smooth start-up without electrical jolts.
Results: Restored performance and reduced noise
After restarting, the Fujitsu heat pump regained optimal thermal efficiency :
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Indoor blowing temperature: 10.5°C in air conditioning mode .
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Noise level: reduced by more than 50% thanks to the new fan balancing.
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Smooth drainage: no more water accumulation or gurgling noise.
The satisfied customer immediately noted that the noise in the garage was now almost imperceptible , a significant improvement for the co-owners of the neighboring spaces.
AirGreen Tips for Heat Pumps Installed in Underground Garages
Units suspended in garages or closed parking lots require special attention:
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Ensure sufficient ventilation around the unit to avoid excessive condensation.
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Inspect the mounting rods annually to prevent corrosion.
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Have the refrigerant level checked before each winter: micro-leaks can be accentuated by temperature variations.
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Clean the drain pipe to prevent internal ice formation.
At AirGreen, we recommend annual preventative maintenance for these special installations, which are often overlooked but subject to extreme conditions.
AirGreen: precision, safety and sustainability
This project in Lachine demonstrates our ability to intervene in complex technical environments , where safety, precision and durability must go hand in hand.
Our specialized technicians master the particularities of Fujitsu, Midea, Lennox, Gree, Sharp and Daikin systems, whether they are installed on exterior walls, balconies, roofs or suspended structures.
Each AirGreen repair aims to restore comfort, reduce energy consumption and extend the life of the HVAC system , whether in Montreal, Laval, Longueuil, on the North Shore or the South Shore .
AirGreen — Experts in residential and commercial HVAC system repair and maintenance throughout Greater Montreal.