A sudden loss of heat in a single-family home
At AirGreen , we were recently called to Sainte-Julie , on the South Shore of Montreal, for a service call regarding a Goodman central heat pump installed on a single-family residence. The customer had noticed that the outdoor unit was working, but the air blowing through the ducts was lukewarm , even when the thermostat was set to heating mode.
The heat pump in question, a Goodman 3.5-ton (42,000 BTU) , powers a central ducted system serving the entire house. This type of installation is very common in the residential suburbs of Sainte-Julie, Boucherville, and Saint-Bruno, where homes offer enough space for a complete HVAC system with an outdoor condenser and an indoor electric furnace.
Initial diagnosis: a heat pump in prolonged defrost mode
Upon our arrival, our technician performed a visual inspection of the outdoor unit. It appeared to be in good condition, but one detail immediately caught our attention: the compressor was running continuously, while the coils were covered in a thin layer of frost . This symptom indicated an abnormally long defrost cycle .
We then used a professional infrared thermometer to measure the discharge temperature. It was hovering around 22.5°C , whereas in heating mode it should be above 35°C . The problem was therefore probably due to an imbalance in the defrost cycle or a faulty sensor .
Checking the sensors and control board
We opened the condenser electrical panel to test the defrost control board . The coil temperature sensor was sending an erroneous reading, falsely signaling to the board that the coil was frozen, which kept the system in continuous defrost.
Diagnostic steps:
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Reading error codes on the electronic board.
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Testing the thermistor sensor using a digital multimeter.
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Comparison with nominal resistance values provided by Goodman.
Result: the sensor displayed a resistance corresponding to a temperature of -10°C , while the actual surface of the coil was at +5°C . We therefore confirmed that the sensor was defective .
Intervention: sensor replacement and complete cycle check
Our technician replaced the defrost sensor (thermistor coil sensor) with a genuine Goodman part and then reset the control board. After restarting, the system ran a normal defrost cycle for a few minutes before resuming heating.
We measured the temperature at the indoor air vent again:
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before repair: 22.5°C ;
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after repair: 38.7°C .
The difference of more than 16 degrees immediately confirmed that the heat pump was operating at full capacity.
Results: comfort restored and efficiency restored
In less than two hours, our AirGreen team has:
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diagnosed a sensor error ;
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replaced the defective part;
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checked the R410A refrigerant charge ;
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cleaned the condenser fins and checked the electrical connections.
The customer found stable and efficient heating , while reducing unnecessary electricity consumption generated by prolonged defrost cycles.
Why use AirGreen in Sainte-Julie and on the South Shore?
Goodman central heat pumps are renowned for their robustness, but like any HVAC system, they require rigorous maintenance and professional diagnosis in the event of a drop in performance. At AirGreen , we operate in Montreal, Laval, Longueuil, and on both shores , with in-depth expertise on all brands: Goodman, Trane, Midea, Gree, Lennox, Fujitsu , and more.
Our technicians are trained to:
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quickly diagnose electronic faults ;
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adjust defrost control settings ;
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ensure optimal performance of your central system, summer and winter.
Preventive maintenance: actions that make the difference
To avoid this type of breakdown, we recommend our customers:
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to have the outdoor condenser cleaned every spring;
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to check the sensors and electrical connections in the fall;
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to change the air filters every 2 to 3 months;
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and schedule an annual AirGreen inspection before each heating season.
Regular maintenance helps prevent costly breakdowns and extends the life of the compressor, board and sensors.
In conclusion, this Goodman central heat pump repair in Sainte-Julie once again demonstrates our rigor and technical know-how. Thanks to our rapid intervention and the exclusive use of original parts , the system has regained its maximum performance, ensuring the owner constant comfort and exemplary energy efficiency .