HVACopediaCarrier · Air conditioner
65 DC bus voltage low - speed limiting
What the control is telling you
Amber STATUS light flashes 65. Inverter DC voltage is low, so the unit limits speed. Type: Local; reset: Automatic.
Applies to: Carrier Infinity 19VS variable speed air conditioner 24VNA9 (AOC control + inverter)
Likely causes
- Low supply voltage (under about 197 VAC)
- Loose wire in the control box
- Shutdown caused by another fault code
- Inverter internal damage
Test and repair steps
- Measure supply voltage at the outdoor unit; if low, contact the utility.
- Check for loose wires in the outdoor control box.
- Check for other fault codes; if none and voltage is good, replace the inverter.
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Source: Carrier 25VNA8 / 24VNA9 Service Manual, Table 6 Fault Code Actions, p.21. Summarized in our own words; check the original manual for your model.
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