Heating problem in the middle of winter: emergency call to AirGreen
It was in a charming house in the residential neighborhood of Saint-Lambert , on the South Shore of Montreal , that our AirGreen team was called upon for an unusual HVAC service call . In the middle of February, the customer noticed that his Sharp wall-mounted air conditioner , installed above a patio door, was no longer producing warm air. The unit, usually used in heat pump mode for supplemental heating, was blowing lukewarm air despite a freezing outside temperature.
Initial observation: an old but robust device
The indoor unit, a Sharp ZU1 series wall-mounted model , had been installed for several years in a busy area of the house—a living room that opened directly onto the garden. The setup wasn't ideal: the hot air outlet blew directly onto the glass door, which was exposed to cold drafts. So we started by:
-
Check the operating mode and the set temperature .
-
Examine the fan blades and interior temperature sensor .
-
Measure the refrigerant pressure from the outdoor unit located behind the house.
Our tests confirmed a loss of efficiency of the thermodynamic cycle , caused by a partial lack of refrigerant — a typical problem after several winters without preventive inspection.
Precise diagnosis: micro-leak at a flare fitting
Upon opening the refrigeration pipe cover, our technicians detected a micro-leak at a flare fitting connecting the compressor to the copper line. This type of leak, often imperceptible to the naked eye, manifests itself as a fine trace of oil on the pipe and a gradual decline in performance.
We confirmed the diagnosis with a nitrogen pressure test before proceeding with the repair.
Repair steps: rigor and safety above all
Our team proceeded as follows:
-
Complete draining of the remaining refrigerant in the system in accordance with environmental standards.
-
Disassembly and cleaning of the defective flare fitting , followed by replacement with a new reinforced copper connection.
-
Pressure gauge leak test at 400 psi for 30 minutes to ensure no leaks.
-
Complete system recharge with R410A refrigerant according to Sharp nominal pressure.
-
Recommissioning and temperature calibration.
Result: restored heat and optimized efficiency
As soon as I turned it back on, the difference was instantaneous. The Sharp air conditioner regained its full heating capacity, distributing a constant and pleasant warm air. We also noticed an improvement in the fan speed and a perfect stabilization of the defrost cycle .
The customer, relieved to be able to heat his main room without resorting to his electric backup system, emphasized the discretion and cleanliness of the intervention - a point of honor for every AirGreen technician.
Advice given to the owner
Before leaving the premises, we reminded the client of the importance of annual maintenance of the wall-mounted heat pump :
-
Check gas pressure and outdoor coil cleanliness before each winter.
-
Keep the area around the unit clear of any obstacles.
-
Have flare fittings and electrical cables checked at least once a year.
We also slightly repositioned the direction of the airflow so that it no longer hits the door directly, thus optimizing thermal distribution in the room.
AirGreen: HVAC expertise for sustainable comfort
At AirGreen , every intervention combines in-depth technical diagnosis , sustainable repair and compliance with environmental standards . We quickly intervene on all types of HVAC equipment — heat pumps, wall-mounted air conditioners, multi-zone systems, air exchangers — in Montreal, Laval, Longueuil, on the North Shore and the South Shore .
This repair in Saint-Lambert perfectly illustrates our commitment: to extend the lifespan of existing equipment before recommending replacement, while ensuring optimal energy efficiency for each home.