HVACopediaCarrier · Heat pump
97 DC over voltage lockout
What the control is telling you
Amber STATUS light flashes 97. Inverter DC voltage kept going too high (elevated from code 91). Type: System malfunction; reset: 2 hours.
Applies to: Carrier Infinity 18VS variable speed heat pump 25VNA8 (AOC control + inverter)
Likely causes
- High supply voltage (over about 253 VAC)
- Inverter internal damage
Test and repair steps
- Measure supply voltage at the outdoor unit; if high, contact the utility.
- Replace the inverter if supply voltage is normal.
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Source: Carrier 25VNA8 / 24VNA9 Service Manual, Table 6 Fault Code Actions, p.25. Summarized in our own words; check the original manual for your model.
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