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Réparation d’une thermopompe murale Goodman sur toit-terrasse — Plateau-Mont-Royal (Montréal)
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Repair of a Goodman wall-mounted heat pump on a rooftop terrace — Plateau-Mont-Royal (Montreal)

On this type of building, typical of the Plateau-Mont-Royal neighbourhood , you often find outdoor units installed on the roof , like the one shown in the photo: a Goodman heat pump mounted on a concrete slab, with anti-vibration mounts, insulated refrigerant lines, and discreet routing to the interior. This type of installation is efficient… but it requires a very rigorous maintenance approach, because the conditions on a roof (sun, wind, extreme temperature variations, UV radiation, humidity) accelerate the wear and tear of certain components.

At AirGreen , we regularly work on Goodman wall-mounted heat pumps of this format (ductless system / mini-split), and this case perfectly illustrates a common situation in urban areas: performance gradually decreasing, then intermittent shutdowns, without the customer being able to clearly identify the cause.

Context and observed symptoms (unstable comfort in air conditioning and heating mode)

The client contacted us because the comfort level had become inconsistent:

  • slower cooling on hot days;

  • shorter cycles, sometimes with stops;

  • impression that the unit “forces” more;

  • Noise/vibration is more noticeable than before, especially when the compressor starts.

On a Goodman wall-mounted heat pump installed on the roof, these symptoms can originate from a mechanical issue (ventilation, vibration, support) as well as a refrigerant issue (charge, restriction, micro-leak), or even an electrical issue (power supply, capacitor, exposed connections).

AirGreen Diagnostic: a comprehensive approach, without assumptions

On site, we proceeded as is systematically done on rooftop outdoor units:

  1. Visual inspection of the installation

    • checking the stability on the slab and the anti-vibration blocks;

    • checking clearances around the grille and fan;

    • state of insulation on the lines (UV, cracks, crushed areas);

    • electrical box inspection and cable routing.

  2. Electrical checks

    • measurement of supply voltages at startup and during operation;

    • inspection of connections (tightness, traces of oxidation, moisture);

    • control of startup components according to observed behavior.

  3. Performance monitoring and operating parameters

    • blowing temperatures on the inside (difference before/after stabilization);

    • behavior of the outdoor fan and regularity of rotation;

    • heat transfer check (sign of dirty exchanger or inadequate charge).

  4. Validation of the refrigerant circuit

    • search for signs of micro-leaks (oil, localized dirt, traces on fittings);

    • control of fittings accessible at the service point;

    • validation of the integrity of the insulation (degraded insulation can impair operation and cause losses in efficiency).

Most likely cause in this case: a combination of factors related to the roof (UV rays + vibrations + connections).

In this case, the painting corresponded to a very common scenario on rooftop terraces:

  • line insulation weakened by UV rays , with less airtight sections;

  • micro-movements/vibrations transmitted through the support, which eventually put stress on the fittings;

  • an efficiency that gradually decreases, then the unit compensates until it becomes unstable.

In other words: it was not “a single major failure”, but a combination of factors typical of an exposed outdoor installation.

Repair: restoration + prevention (to avoid the problem recurring)

Our intervention was not limited to "getting the machine running again". The objective was to stabilize the system and increase its reliability on the roof.

1) Upgrading of critical components

  • reworking of sensitive points (accessible connections) with leak testing;

  • securing sections of the line where the insulation was damaged;

  • targeted cleaning of the outdoor heat exchanger (a dirty heat exchanger on the roof = efficiency drops faster than you think).

2) Vibration reduction and installation protection

  • verification/adjustment of the support and anti-vibration mounts;

  • improved line securing to limit movement;

  • increased protection of the insulation against UV rays (a simple but crucial detail on a roof).

3) Final validation

After the repair, we always validate:

  • stability of cycles (no more unexpected stops);

  • return of normal heat exchange;

  • smoother operation (less vibration/noise);

  • Interior comfort restored and response time improved.

Result: restored comfort, stabilized performance, and a reassured customer

At the end of the intervention, the Goodman wall-mounted heat pump returned to stable operation:

  • more constant cooling;

  • normal cycles;

  • reduced noise;

  • better customer confidence, especially important in condos (where every discomfort is quickly felt).

Key takeaways (special report on roofing in Montreal)

A Goodman unit installed on the roof works very well… provided that certain points are monitored:

  • line insulation (UV = enemy #1);

  • vibrations and stability of the support;

  • cleanliness of the exchanger (dust, pollen, deposits);

  • electrical inspection (humidity and temperature variations play a role).

At AirGreen , it is precisely this type of detail that makes the difference between a “temporary” repair and a lasting return to service.