Armstrong Air
Outdoor Unit No-Start
Outdoor unit will not start at all, indoor blower runs and thermostat appears normal
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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
Tripped outdoor breaker or blown fuses, Failed contactor coil, Broken low-voltage wire to condenser, Open high- or low-pressure safety switch
How to Fix / Troubleshooting
Safety first: High voltage present. Turn off the breaker and outdoor disconnect before opening the condenser panel.
Steps:
- 1. Verify power: Check the AC breaker in the main panel and the outdoor disconnect. Reset once if tripped.
- 2. Listen for contactor click: With power on and a call for cooling, listen at the outdoor unit. If you do not hear a click, the contactor may not be energizing.
- 3. Inspect low-voltage wiring: Remove the control panel cover and check the two small-gauge wires from the house to the contactor coil. Ensure they are intact and firmly connected.
- 4. Check safety switches: Many Armstrong Air units wire high- and low-pressure switches in series with the contactor coil. Inspect these switches and their wiring for damage or loose connections.
- 5. If contactor coil has 24V but does not pull in: The contactor is defective and should be replaced.
- 6. If no 24V is present at the contactor: There is a control issue upstream (thermostat, indoor board, transformer, or safety switch) that may require a technician.
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Repair Difficulty
Hard
4/5
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