A quick service call for an appliance that was no longer cooling
At AirGreen , we respond weekly to issues related to Daikin wall-mounted systems in the Côte-des-Neiges–Notre-Dame-de-Grâce area. This time, our client contacted us after noticing that their Daikin wall-mounted air conditioner was blowing lukewarm air, despite the thermostat being set at 19°C.
The air conditioner, installed about six years ago, appeared to be in good visual condition, but interior comfort had deteriorated significantly over the past few days.
Diagnosis: Lack of performance caused by a dirty sensor
Upon our arrival, we immediately performed a complete analysis of the HVAC system .
Initial observations:
-
The indoor unit turned on normally.
-
The swinging shutter responded well to the command.
-
No errors were displayed on the wall controller screen.
-
However, the blowing temperature remained constant at 23°C, without dropping despite the compressor being on.
Using our Fluke infrared thermometer , we compared the suction and discharge temperatures. The difference was only 2°C, indicating poor temperature detection by the internal sensor (thermistor) .
This sensor, clogged by dust accumulated in the unit's shell, sent erroneous values to the electronic card, preventing the compressor control from correctly modulating the refrigeration cycle.
Step 1: Disassembly and deep cleaning
We carefully disassembled the front of the Daikin FTXS12 , removed the filters and exposed the sensor.
Using an anti-static brush and a dry air spray , we cleaned the thermistor area as well as the evaporator.
Cleaning this component is crucial: even a thin layer of dust can throw off the temperature reading by several degrees, which is enough to disrupt the entire cooling cycle.
We also cleaned:
-
Fine mesh filters , often overlooked.
-
The condensate tray , slightly blocked by deposits.
-
The evaporator fins , in order to restore optimal air circulation.
Step 2: Electrical verification and calibration
After cleaning, we checked the supply voltage of the electronic module: stable 230 V.
We then recalibrated the temperature sensor using the Daikin built-in diagnostic mode.
The system immediately recognized the new reading, and the blowing temperature dropped to 13°C in less than 10 minutes—a sign of restored operation.
Step 3: Check the outdoor condenser
To ensure that the cause was not a loss of refrigerant, we inspected the outdoor Daikin condenser , located on the rear balcony.
The pressures were normal, no signs of oil or leaks.
So we confirmed that the fault was only due to the dirty sensor and not a refrigerant problem.
Result: restored comfort and optimal performance
After the restart, the customer immediately noticed an improvement in comfort .
The cold airflow was stable and the room reached the set temperature in less than 15 minutes.
We explained to the client the importance of biannual cleaning , particularly in an urban environment like Côte-des-Neiges where dust accumulates quickly.
AirGreen's expertise in HVAC maintenance and repair
At AirGreen , we combine precise diagnosis , professional tools and rapid interventions to maintain the performance of wall systems in Montreal and the surrounding area.
Our certified technicians:
-
Diagnose electronic and mechanical faults.
-
Cleans and disinfects internal components.
-
Repair or replace genuine parts for Daikin, Fujitsu, Gree, Sharp, Midea, and many others.
-
Check the pressures, load and energy consumption of each device.
Our service covers all of Greater Montreal , including Laval, Longueuil, the North Shore and the South Shore .
AirGreen Tips to Extend the Life of Your Daikin Air Conditioner
To avoid a similar problem happening again, we recommend:
-
Clean the filters every four weeks during the warm season.
-
Turn off the unit completely before dusting.
-
Plan for annual professional maintenance , including checking sensors, drainage and the electronic card.
-
Leave the unit in fan mode for 10 minutes after turning off the air conditioning to remove internal moisture—a simple step that prevents odors and corrosion.
Another concrete example of AirGreen reliability
This type of intervention perfectly illustrates the AirGreen philosophy: offering a reliable, transparent and rapid technical service, without unnecessary replacement of components.
In less than an hour, we reconditioned a Daikin wall-mounted air conditioner , guaranteeing the customer lasting comfort for the summer season.