HVACopediaGoodman · Heat pump
L8 Low line voltage
What the control is telling you
Line voltage measured below 185 VAC. Unit may appear to run normally or the compressor may be off on its protector. Clears when voltage goes back above 185 VAC.
Applies to: Communicating 2-stage condensers and heat pumps with the PCBHR104 or PCBHR105 outdoor control (7-segment display): ASXC16/18, GSXC16/18, DSXC16/18, ASZC16/18, GSZC16/18, DSZC16/18
Likely causes
- Low supply voltage
- Undersized or long supply wiring, loose connections
Test and repair steps
- Warning: Kill power to the outdoor unit before touching wiring, the compressor terminals or the control.
- Measure line voltage at the unit during compressor start and run.
- Check breakers, fuses and connections; confirm supply matches the rating plate.
- Correct wiring or contact the utility if the supply is low.
Models that show this code
24 models in Goodman/Amana ComfortNet ASZC/GSZC/DSZC
Other codes on the same units
- d4 Shared data from the loader rejected
- E5 Outdoor control low-voltage fuse open
- H8 High line voltage
- L1 Lockout - low pressure switch tripped 3 times
- L2 Lockout - high pressure switch tripped 3 times
- L6 Lockout - open start circuit detected 4 times
- L7 Lockout - open run circuit detected 4 times
- P0 Compressor protector open
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Source: Goodman ComfortNet ASXC/GSXC/DSXC, ASZC/GSZC/DSZC, AVPTC/MBVC service manual, Unitary Diagnostic Codes PCBHR104 p.71-77 and PCBHR105 p.78-84. Summarized in our own words; check the original manual for your model.
Homeowner looking at this code? See what it means for you and when to call a technician.
For licensed technicians. Gas, electrical and refrigerant work must be done by a qualified, licensed person. Shut off power and gas before servicing, never bypass a safety control, and follow the manufacturer’s manual for the exact model; it and local codes always take priority. HVACopedia is not affiliated with any manufacturer; brand and model names only identify the equipment.