Amazon Smart Thermostat
Cooling Call Without Compressor Operation
Thermostat shows cooling is on but warm air blows from vents (conventional AC system)
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Safety Warning
This repair may involve working with high voltage components or water connections. Always unplug the appliance before removing any panels.
If you are not confident in your ability to perform this repair safely, we strongly recommend contacting a professional technician.
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Possible Causes
Outdoor unit not powered, Open contactor coil circuit, Broken Y wire to outdoor unit, Low-pressure safety switch open
How to Fix / Troubleshooting
Safety: Turn off power to the outdoor unit at the disconnect before opening any panels.
- Check outdoor unit: Listen for compressor and fan operation. If silent, verify the outdoor breaker and disconnect are ON.
- Inspect Y wiring: Confirm the Y wire from the thermostat is connected at the furnace/air handler and that the cable to the outdoor unit is intact.
- Look for tripped safety switches: Some systems have low-pressure or float switches that open the Y circuit. Check for water in the drain pan or signs of refrigerant issues (technician required).
If the thermostat is sending a Y signal but the outdoor unit does not run, an HVAC technician should diagnose the outdoor unit and safety circuits.
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Repair Difficulty
Professional Required
5/5
Required Part
Outdoor Condenser Contactor Coil / Low-Voltage Y Circuit
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