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Réparation d’une thermopompe centrale Carrier à Saint-Constant
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Repair of a Carrier central heat pump in Saint-Constant

Technical intervention in the underground parking of a residential building

At AirGreen , we are often called upon to intervene in complex technical contexts: condo buildings, underground parking lots, or industrial facilities where space and ventilation are limited. This was the case during this service call in Saint-Constant , on the South Shore of Montreal , for a Carrier central heat pump installed in an indoor garage.

The condensing unit, suspended from the ceiling above the parking spaces, was showing signs of malfunction that were compromising the comfort of several of the building's co-owners.

The first signs of the problem

The building manager contacted us after receiving several complaints from occupants:

  • No heating in some units.

  • Intermittent shutdowns of the main heat pump.

  • Abnormal noise level from the compressor.

  • Condensation buildup around the hanging unit.

A preliminary visual inspection revealed that condensation was draining poorly , probably due to a blocked drain or poor insulation of the refrigeration ducts .

But the origin of the problem turned out to be more complex.

In-depth on-site diagnosis

Our certified technicians carried out a series of tests to identify the source of the fault:

  1. Refrigeration cycle check : operating pressures were lower than normal, indicating a partial deficit of R410A refrigerant .

  2. Condenser fan check : The motor was running, but the blade was vibrating slightly—a potential indicator of imbalance due to mechanical wear .

  3. Defrost system inspection : the electronic module was no longer sending the correct signal to the reversing valve.

  4. Review of wiring and electrical connections : A loose connection on the control board was causing sporadic interruptions in communication between components.

Using a systematic approach and the use of a digital pressure analyzer , we were able to confirm that the fault was caused by both a slow leak on a refrigeration line and a faulty electronic control board .

Complete and safe repair

The underground parking environment imposed several constraints:

  • Limited ceiling height.

  • Vehicle traffic during the works.

  • Obligation to protect neighboring vehicles against dust and projections.

To ensure a safe and trouble-free repair, our team proceeded as follows:

  1. Isolation of the work area with tarpaulins and safety cones.

  2. Complete recovery of the refrigerant gas before opening the circuit.

  3. Nitrogen leak detection then silver brazing on the damaged section.

  4. Replacement of the electronic card with an original Carrier part.

  5. Pressure test and complete vacuum draw of the circuit.

  6. Recharge the system to the pressure recommended by the manufacturer.

  7. Restart and observation over full cycle to ensure return to nominal performance.

Final result

Once the repair is complete:

  • The unit's sound level has returned to normal.

  • Blowing temperatures have returned to their initial efficiency.

  • Condensate now drains properly, without leaks or overflow.

  • The manager received a complete maintenance report with before/after photos and technical measurements.

Expertise adapted to complex environments

Central heat pumps installed in underground parking lots require specific expertise. At AirGreen:

  • We master the intervention protocols in confined spaces .

  • We comply with safety and mechanical ventilation standards .

  • We have the necessary equipment to work on suspended units , even several meters above the ground.

Our goal remains the same: to maximize the performance and durability of each HVAC system, while limiting disruptions to occupants.

Recommended prevention and maintenance

To avoid similar breakdowns on comparable installations, our experts recommend:

  • A biannual preventive inspection including checking pressure, probes and condensates.

  • Regular cleaning of the condensation drain .

  • An annual check of the refrigerant gas to detect micro-leaks before they compromise performance.

  • Updating the control module software when recommended by the manufacturer.

Conclusion

This intervention in Saint-Constant perfectly illustrates the rigor and versatility of our AirGreen team. By simultaneously correcting a refrigerant leak and an electronic fault in a confined environment, we restored optimal operation of the Carrier central heat pump while ensuring the safety of the premises and the satisfaction of the residents.

Thanks to our recognized expertise throughout Greater Montreal , we guarantee our clients—whether they are owners, managers or co-owners— durable, professional and certified solutions for their HVAC systems.