Invalid model plug / inverter size: the control does not accept the model plug for this inverter.
Carrier 25 is an invalid model plug. It is not a pressure code and not a voltage code. The amber status LED flashes 2 short and then 5 long. The control does not accept the model plug fitted to this inverter. Listed causes are a missing plug, the wrong plug, a damaged plug, a plug that is not fully seated, a plug that does not match the inverter size (the manual's example is a 2 ton plug on a 3 ton inverter), and a damaged AOC control. Both steps are for a technician: confirm the plug and its resistance against the wiring diagram, seat it to the silkscreen, and replace the plug, the inverter, or the AOC if that part is damaged. Code 25 has no coil check and no filter check.
Likely causes
- Missing model plug
- Wrong model plug installed
- Damaged model plug
- Model plug not fully engaged on the board
- Model plug does not match the inverter size (for example a 2 ton plug on a 3 ton inverter)
- Damaged AOC control
Safe checks for 25
- Technicianinstall or verify the correct model plug, check it for corrosion or breakage and check its resistance per the wiring diagram
- Technicianalign the plug per the silkscreen layout; replace the plug or inverter with the correct size, or replace the AOC control if it is damaged
Capacitors can hold a charge after the power is off. Safety terms.
When to call a pro
Call a licensed HVAC technician: this is a configuration fault on the outdoor control board.
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