A service call reveals a lack of refrigerant
At AirGreen , we regularly respond to performance issues with Tosot wall-mounted heat pumps , which are very popular in and around Montreal. This time, our team was called to Sainte-Catherine , on the South Shore, to diagnose a Tosot outdoor unit showing signs of weakness in air conditioning mode: warm air, a drop in pressure, and irregular compressor noise.
Context of the intervention
The client, the owner of a typical brick duplex in the area, informed us that his wall-mounted heat pump —installed approximately four years ago—was no longer maintaining the indoor temperature, despite annual maintenance. The Tosot outdoor unit, securely mounted on a metal wall bracket, appeared to be working, but the temperatures measured at the air outlet no longer met the expected specifications.
After visual inspection, we quickly identified the presence of oil on the service connection, a classic sign of a micro-leak of refrigerant .
Accurate diagnosis thanks to our professional tools
To confirm our hypothesis, we connected our digital pressure gauges and an electronic scale to accurately measure the system pressure and load. The observed values were nearly 40% lower than the standard recommended by Tosot for this 12,000 BTU model.
We then proceeded to:
-
A nitrogen leak test to locate the leak.
-
A soapy water inspection on the flare fittings.
-
A vacuum pressure analysis to ensure circuit cleanliness.
Result: a micro-leak at the liquid line connection , probably due to mechanical tension or slight loosening over time.
Complete system repair and recharge
Steps of the intervention:
-
Tightening and replacing the flare joint at the defective location.
-
Complete vacuum to eliminate all traces of humidity.
-
Recharge with R410A refrigerant according to the exact quantity specified by the manufacturer Tosot.
-
Check subcooling and superheat to ensure optimal performance.
-
Final performance test : pressure, temperature and air flow measurements confirming return to nominal efficiency.
The photo above illustrates this charging phase: the pink refrigerant bottle connected via an electronic manifold to the Tosot outdoor unit, installed on the typical red brick wall of the house.
Results and customer satisfaction
Once the charge was complete, the heat pump immediately returned to its original efficiency:
-
Indoor blown air temperature: 7°C lower than before repair.
-
Stabilized electricity consumption.
-
Normalized compressor noise level.
The customer could feel the difference from the first minutes: fast, quiet and stable cooling . We also recommended an annual inspection to prevent any future loss of performance or microleaks.
AirGreen Expertise: Beyond Simple Repair
At AirGreen , every service call is an opportunity to demonstrate our technical rigor and expertise in residential HVAC systems . We treat each brand with care—from Tosot to Midea , Fujitsu , Sharp , and many others—and scrupulously follow the manufacturers' recommended diagnostic protocols.
Our certified technicians ensure that:
-
Each refill is accurate to the nearest gram .
-
The fittings are inspected with nitrogen after tightening.
-
The customer receives a clear explanation of the problem and preventive solutions.
It is this meticulous and transparent approach that makes us a HVAC reference on the South Shore, in Montreal, Laval and on the North Shore .
Maintenance tips to extend the life of your Tosot heat pump
To prevent similar problems from recurring:
-
Clean the internal filters every two months.
-
Keep the fins of the outdoor unit clear (no obstructions, vegetation or dust).
-
Schedule an annual professional maintenance , including pressure check and leak test.
-
Avoid excessive vibration : it can loosen flare fittings over time.
Conclusion: a high-performance and reliable Tosot heat pump thanks to AirGreen
This Tosot wall-mounted heat pump repair in Sainte-Catherine perfectly illustrates our commitment: rapid diagnosis, lasting repair, and restored performance . Thanks to our precision tools and our field experience, we restore each HVAC system to its full power and efficiency, regardless of the brand or the complexity of the breakdown.
AirGreen – Experts in HVAC system repair and maintenance in Montreal, Laval, Longueuil, North Shore and South Shore.