Goldstar wall-mounted heat pump repair on a condo rooftop in Ville-Marie (Montreal)

On the flat roofs of condo buildings in Ville-Marie, the outdoor units are exposed to everything: urban dust, freeze/thaw cycles, wind, rain, summer heat… and this always ends up impacting performance. The photo clearly shows a set of Goldstar compact condensers installed on a gravel roof, resting on wooden beams , with electrical disconnect boxes and insulated refrigerant lines converging at a roof vent (black cover). This is typical of a wall-mounted heat pump (mini-split) system serving several condo units.

In this type of setup, a single machine that breaks down can make all the difference: discomfort in a unit, noise complaints, overconsumption, or heating that no longer keeps up on colder days.

The system in place: what can be deduced from the installation

Here we have Goldstar wall-mounted heat pumps (compact outdoor unit, side venting), probably an Inverter generation (size and common use in condos). The exact model isn't visible in the photo, so we're deliberately being realistic: a residential Goldstar “Inverter” wall-mounted heat pump installed on the roof, with insulated lines and dedicated electrical protection.

Important details should also be noted:

• Gravel roof : mineral dust + fine debris that settles on the coils.

• Support on wood : common, but it changes over time (leveling, vibrations, sagging).

• Traces of oxidation visible on some grids/screws: sign of prolonged exposure and humidity.

• Grouping several units together : risk of sound resonance and more complex access for the service.

A typical problem observed on this type of Goldstar roofing

In this scenario (roof + multi-unit + exposure), the most frequent symptoms our technicians encounter are:

• Decreased performance (slow cooling in summer, insufficient heating in autumn/winter)

• Short cycles (the machine starts/stops frequently)

• Abnormal noise (vibrations on support, fan, resonance of the pipes)

• Unusual frost or excessively frequent defrosting in heating mode

• Intermittent error codes related to pressure, sensors, or communication

Our diagnostic approach (AirGreen method)

On a Goldstar wall-mounted heat pump installed like this one, we follow a precise sequence, because a “symptom” can hide two causes (mechanical + refrigeration, or electrical + airflow):

1. Complete visual inspection

   • Condition of the external coil (fouling, debris, corrosion)

   • Condition of pipe insulation (cracks, UV damage, crushed sections)

   • Unit level and contact points (vibrations/transfer to the support)

   • Disconnect box, wiring, sealing of inlets

2. Electrical checks

   • Supply voltage and stability

   • Tightening of connections

   • Communication control (depending on configuration)

   • Search for traces of oxidation or moisture in the casings

3. Refrigeration controls

   • Pressure and temperature measurements during operation

   • Overheating/subcooling analysis (depending on conditions)

   • Leak detection if low load indicators (oil, fittings, valves)

4. Functional test

   • Air conditioning mode and heating mode

   • Defrosting (if season/conditions permit)

   • Noise/vibration assessment under load

Repair: interventions carried out in a realistic and sustainable manner

On a rooftop installation like this, effective repair is not just about "getting the unit working again": it is about correcting the cause and ensuring reliability.

Based on our observations, our typical interventions include:

• Technical cleaning of the external coil (dust/gravel deposits, fine particles)

• Resumption of vibration points

  • Adjusting the positioning on the beams

  • Adding/replacing anti-vibration pads

  • Correcting the contact of the pipes to avoid resonance

• Localized repair of line insulation (sections cracked or degraded by UV)

• Electrical control/tightening in the disconnection and service compartment

• If a refrigerant charge is the cause:

  • Leak test , repair as needed (fitting/valve)

  • Vacuum extraction according to best practices

  • Proper charging and validation of operating parameters

The goal: a Goldstar that regains its stability, without extraneous noise, with consistent pressures and normal performance.

Results observed after intervention

Once the Goldstar heat pump is back in working order:

• Comfort becomes constant again (stable temperature, fewer variations)

• The machine cycles less , works more smoothly, which reduces wear.

• The noise level decreases significantly when the vibrations and contact points are adjusted.

• The customer regains confidence : a more predictable system, fewer surprises, and greater efficiency.

Maintenance tips (specifically for gravel roofs)

To prevent the same problem from recurring, we recommend:

• Regular maintenance (especially cleaning of the external coil): gravel roofing accelerates soiling.

• Check the condition of the insulation during seasonal changes (UV + frost = cracks)

• Monitor for any new noises : on the roof, a small vibration can quickly become a major inconvenience.

• Keep access clear around the units for proper air circulation

Why entrust a Goldstar repair to AirGreen

At AirGreen, we are accustomed to the condo configurations of Greater Montreal: rooftop units grouped together , technical access, noise constraints, and clean, structured interventions. Our approach is simple: measured diagnosis, sustainable repair, and complete validation in heating/cooling mode.