A typical service call transformed into a reassuring experience
At AirGreen , every HVAC repair is an opportunity to demonstrate our expertise and commitment to the comfort of Greater Montreal homes. Recently, our team traveled to Sainte-Anne-de-Bellevue , on Montreal's West Shore , to diagnose a Fujitsu wall-mounted heat pump that was no longer adequately cooling a client's apartment located on the second floor of a red brick building.
The context of the intervention
The customer, a long-time AirGreen customer, contacted us after noticing that his outdoor unit was no longer turning on despite the commands on the indoor remote control. The equipment in question: a Fujitsu 12,000 BTU wall-mounted heat pump, approximately 8 years old, used for supplemental heating in the winter and air conditioning in the summer.
The outdoor unit was installed on the balcony, exposed to wind and humidity. Upon arriving on site, our technicians immediately noticed signs of wear:
-
Accumulation of dust and debris on the front grille.
-
Traces of oxidation around the refrigeration connections.
-
Deteriorated refrigeration line insulation, leaving exposed copper.
In-depth diagnosis
After turning off the power supply via the wall circuit breaker, our team undertook a series of systematic checks:
-
Electrical check : stable supply voltage at 240V. No blown fuses.
-
Compressor Inspection : Continuity Test — Normal Results, But Start Relay Trips Randomly.
-
Reading error codes on the control board: error “E0”, indicating a communication fault between the indoor and outdoor unit.
-
Testing the wiring connections : One of the communication wires showed signs of internal corrosion.
The solution provided
After identifying the main problem— a communications cable failure caused by prolonged exposure to moisture—we proceeded to:
-
Complete replacement of the 4-core cable connecting the two units.
-
Cleaning the external fan and the protective grille.
-
Recalibration of the electronic circuit after reconnection.
-
A hot start test to check the unit's response in cooling and heating mode.
Results
In less than an hour, the system was fully operational. The compressor restarted normally, the indoor air temperature stabilized at 19°C after a few minutes, and the customer regained the comfort expected from a well-maintained Fujitsu heat pump.
Technical analysis: why does this breakdown occur often?
This type of failure— a communication error between units —is particularly common in installations exposed to the elements. The cable connecting the wall units carries both the signal and the synchronization of the electronic components. Over time, humidity and freeze-thaw cycles can damage the insulation, causing intermittent blackouts.
To avoid this kind of problem:
-
It is recommended to protect the cables with a waterproof sheath .
-
Inspect electrical connections at least once a year.
-
Clean the outdoor unit regularly , especially before transition seasons.
The key role of preventive maintenance
This intervention perfectly illustrates why regular maintenance is essential. During our visit, we also advised the customer to consider a complete cleaning of the indoor coil and a check of the R-410A refrigerant pressure , scheduled during their next annual visit.
Once again, AirGreen ensures peace of mind
Thanks to our methodical approach and our expertise in repairing Fujitsu heat pumps , we were able to:
-
Quickly identify the cause of the breakdown.
-
Make a lasting repair.
-
Restore the customer's full system performance.
Whether in Montreal, Laval, Longueuil, on the North Shore or the South Shore , our team remains available 7 days a week for any HVAC emergency.
AirGreen — Your trusted HVAC partner in Montreal.
Repair, maintenance and installation of wall-mounted, central and multi-zone heat pumps , with certified and passionate technicians.