A Mitsubishi heat pump breakdown: a revealing service call in Laval
At AirGreen, we regularly work on residential HVAC systems throughout the Laval area, as well as in Montreal, on the North Shore and the South Shore. During this specific service call, our team was tasked with diagnosing and repairing a Mitsubishi Electric Mr. Slim wall-mounted heat pump, installed on the exterior wall of a single-family home.
Upon arrival, several visual and technical clues allowed us to anticipate a more complex issue than a simple temporary breakdown. The outdoor unit, a Mitsubishi MUZ-GE18NA (18,000 BTU), showed signs of advanced wear and installation conditions that required special attention.
Description of the HVAC system in place
The property was equipped with a Mitsubishi wall-mounted mini-split system, consisting of:
- A wall-mounted indoor unit (not visible in the photo but confirmed on site)
- A compact outdoor compressor Mitsubishi Electric Mr. Slim
- An insulated refrigerant piping system in an external duct
- Condensate drainage directed down the wall
This type of system is very common in Laval and in the residential areas of the North Shore, especially for its energy efficiency and its ability to provide heating and cooling.
Symptoms observed by the client
The owner contacted us after noticing several issues:
- Significant decrease in air conditioning performance
- Abnormal noise from the outdoor unit
- Water accumulation at the base of the wall (condensate issue)
- Intermittent system shutdowns
- Damp smell inside
These symptoms are typical of a combined problem involving drainage, refrigerant pressure, and compressor condition.
Complete diagnosis performed by our technicians
Our certified technicians conducted a thorough multi-step diagnosis:
Outdoor visual inspection
- Checking the condition of the Mitsubishi compressor
- Observation of a significant clogging of the heat exchange grille
- Detection of a partially blocked condensate drain
- Poor water drainage on the floor
Refrigeration circuit analysis
- Refrigerant pressure test (R-410A)
- Reading of inlet and outlet temperatures
- Result: insufficient pressure, indicating a possible leak
Electrical check
- Connection inspection
- Start capacitor test
- Electronic board analysis
No major electronic faults, but a notable mechanical efficiency loss.
Identified problems
Following the diagnosis, several problems were confirmed:
- Slight refrigerant leak (R-410A) at the flare fittings
- Condensate drain blockage
- Accumulation of dirt in the outdoor coil
- Beginning compressor fatigue (irregular operation)
- Installation too close to the wall, limiting air circulation
AirGreen intervention: a complete and lasting repair
At AirGreen, we always prioritize a comprehensive approach rather than temporary repairs. Here are the actions carried out during this intervention in Laval:
Refrigeration circuit repair
- Precise leak location
- Tightening and replacement of defective flare fittings
- Complete leak test
- System recharge with R-410A according to Mitsubishi specifications
Thorough cleaning of the outdoor unit
- High-pressure coil cleaning
- Fin decontamination
- Fan inspection
Unblocking and correcting drainage
- Complete cleaning of the condensate drain
- Reconfiguring the drainage slope
- Flow test
Installation optimization
- Adjusting positioning to improve ventilation
- Checking wall mounts
- Unit stabilization to reduce vibrations
Final result: performance restored and client reassured
After the intervention, the results were immediate:
- Return to effective and stable air conditioning
- Elimination of abnormal noises
- Normal condensate drainage
- Reduced energy consumption
- Thermal comfort restored throughout the house
The client especially appreciated the transparency of our diagnosis and the precision of our intervention.
AirGreen expert tips to avoid this type of breakdown
In regions like Laval, Longueuil, or Montreal, where climate variations are significant, HVAC system maintenance is essential.
Here are our recommendations:
- Have your heat pump inspected at least once a year
- Regularly clean filters and the outdoor unit
- Check condensate drainage
- Avoid overly confined installations
- Call on certified professionals for any refrigerant recharge
Why choose AirGreen for your HVAC repairs?
We operate throughout the North Shore, the South Shore, in Montreal, Laval, and Longueuil, with recognized expertise in Mitsubishi systems.
Our strengths:
- Certified and experienced technicians
- Accurate and honest diagnosis
- Durable repairs
- Fast and professional service
- In-depth knowledge of residential HVAC systems