A heating failure in the middle of spring transition
At AirGreen , we recently received a service call in Boucherville , on the South Shore of Montreal , for a Goodman central heat pump that refused to start after a period of mild weather. This type of intervention is common in the spring, when heating and cooling cycles alternate and some systems have difficulty adapting.
The customer, a single-family home owner, reported that the outdoor unit was no longer turning on despite the thermostat's commands. The air blowing through the grilles was lukewarm, and the power consumption seemed higher than usual.
On-site diagnosis: an inactive compressor and a defective relay
Upon our arrival, we conducted a thorough inspection of the Goodman central heat pump , a 3.5-ton model typical of residential installations with air ducts. The outdoor unit was well maintained, securely mounted on its concrete slab, and equipped with a snow and debris protection cap —an accessory we highly recommend to extend the life of condensers in Quebec.
After checking the electrical voltages at the unit's input, our technician quickly noticed that the main contactor was not engaging. By manually forcing the coil, the compressor started correctly, indicating that the fault was in the low voltage control circuit .
Measurements confirmed an irregular voltage of 18V on the thermostat line, while a minimum of 24V is required to activate the relay. The problem therefore stemmed from a faulty relay on the control board .
Repair carried out: replacement of the relay and complete check of the system
Once the diagnosis is confirmed, our team has:
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Turn off the power at the main circuit breaker,
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Removed the control board and replaced the low voltage relay with a new genuine Goodman part,
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Cleaned the connectors and tightened the compressor terminals,
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Checked the continuity of the thermostat cable between the indoor module and the condenser,
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Restarted the system and validated operating pressures with R-410A gauges.
Final measurements demonstrated stable performance:
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Discharge pressure: 230 psi,
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Suction pressure: 120 psi,
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Indoor blowing temperature: 21°C in heating mode.
The customer was able to immediately notice the return of thermal comfort , with a system operating silently and efficiently.
Prevention: maintenance and seasonal checks
We took advantage of this intervention to raise awareness among the client about the importance of biannual preventive maintenance . Voltage fluctuations and natural wear and tear of electronic components are common causes of breakdowns in central heat pumps. To avoid these inconveniences:
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Have the contactor and relay checked every spring,
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Clean the low pressure condenser fins ,
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Maintain the protective hat during the winter,
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Replace the indoor system filter every 3 months.
At AirGreen, we offer preventative maintenance programs adapted to the climatic reality of Greater Montreal, including detailed inspections of the refrigeration, electrical and mechanical components.
AirGreen Expertise in Boucherville and throughout the South Shore
This repair demonstrates our expertise in repairing Goodman central heat pumps , one of the most common systems in Quebec homes. Whether in Boucherville, Longueuil, Saint-Lambert or Sainte-Julie , our certified technicians intervene quickly to diagnose, repair and optimize the performance of any HVAC system.
Thanks to this intervention, the client's central heat pump is now operating at full capacity, ensuring constant comfort and optimal energy efficiency.