A service call for low performance and abnormal pressure
At AirGreen , we were called to intervene in Boisbriand , on the North Shore of Montreal , for a Tosot wall-mounted heat pump that was no longer able to adequately cool the house. The customer noticed that the interior temperature remained high despite continuous operation of the unit. This type of symptom often indicates a pressure imbalance in the refrigeration circuit or a refrigerant leak .
Initial inspection: unbalanced pressures and suspected leak
Our diagnosis began by checking the operating pressures using an analog manifold connected to the Tosot condenser.
The measurements revealed:
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Suction pressure too low , at 85 psi.
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Insufficient discharge pressure , at 215 psi, instead of the 280 psi expected for this model.
These values confirmed a lower than normal amount of refrigerant .
Visual inspection then revealed a slight trace of refrigerant oil at the lower liquid pipe connection, a typical sign of a slow leak.
Step 1: Precise location and repair of the leak
To confirm our hypothesis, we injected a UV tracer into the circuit and used a leak detection lamp .
Result: localized leak at the flare connection of the liquid pipe , probably due to insufficient tightening during a previous installation.
So we have:
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Turned off the power and bled the circuit.
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Re-flare using a tool calibrated for R-410A refrigerant.
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Applied a specialist gasket before tightening to the recommended torque.
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Tested the nitrogen pressure system at 300 psi for 30 minutes — no pressure drop detected.
Step 2: Vacuum and recharge the system
Once the seal was confirmed, we carried out a deep vacuum down to 500 microns to eliminate all traces of moisture.
Then we recharged the system with the exact amount of refrigerant prescribed by the manufacturer Tosot (0.95 kg of R-410A).
The new measurements showed:
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Suction pressure at 118 psi.
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Discharge pressure at 270 psi.
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Blowing temperature 10.5°C lower than the indoor ambient temperature.
The system's energy efficiency has been restored to its original level.
Step 3: Cleaning, securing and checking the fixings
Taking advantage of the intervention, we also:
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Cleaned the Tosot condenser and removed the dust accumulated on the fins.
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Checked the metal wall bracket , slightly corroded at the base.
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Tightened the anchor bolts to stabilize the installation and prevent future vibrations.
We also installed an insulating connection cover on the refrigeration pipes to improve durability and reduce heat loss.
Result: restored comfort and maximized efficiency
As soon as it was restarted, the Tosot wall-mounted heat pump returned to a stable operating cycle and rapid cooling of the main rooms.
The customer immediately noticed the difference: the blown air was again fresh, constant and quiet.
Post-repair performance records confirmed:
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Complete and balanced refrigeration cycle .
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Power consumption reduced by approximately 12% according to the power meter reading.
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Standardized condenser noise level .
AirGreen Tips to Prevent Yield Loss
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Have your refrigeration pressures checked once a year, even if you are not experiencing symptoms.
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Inspect flare fittings after each winter: freeze/thaw cycles can loosen them.
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Keep the condenser clean and clear , especially during the summer.
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Watch for traces of oil : they often indicate a leak before it becomes critical.
AirGreen expertise in Boisbriand and across the North Shore
At AirGreen , every repair is carried out with rigor and precision, whether it is for a Tosot, Fujitsu, Midea, Sharp or Zephyr heat pump .
We operate in Boisbriand, Laval, Montreal, Longueuil, and throughout the North Shore and South Shore , with the same objective: to extend the lifespan of your HVAC equipment while optimizing its performance.
Thanks to meticulous diagnosis and professional measuring tools, we guarantee our customers a sustainable, precise and transparent service , always in compliance with the strictest environmental standards.