HVACopediaKeepRite · Air conditioner
46 Brown-out (low voltage)
What the control is telling you
Single-stage boards (and C4A3/CXA6 board): 24 V control voltage below 15.5 V for 4 s; runs again at 17.5 V or more. Two-stage boards: line voltage below 187 V for 4 s; runs again above 190 V.
Applies to: KeepRite C4A3/CXA6 AC with outdoor control board; *SA5/*SA6 AC and *SH4/*SH5/*SH6 HP single-stage communicating; *CA7/*CA9 AC and *CH6/*CH9 HP two-stage communicating
Likely causes
- Weak or overloaded 24 V transformer
- Low utility line voltage
- Loose power or control wiring
Test and repair steps
- Single-stage / C4A3-CXA6 measure 24 V at the outdoor board - it should be 18-30 V. Check transformer size and load.
- Two-stage measure line voltage at the contactor under load.
- Tighten loose connections and recheck.
Settings for these units
Outdoor unit clearances · KeepRite C4A3/CXA6 AC
| Location | Minimum |
|---|---|
| Service end | 24 in. (610 mm) |
| Above unit | 48 in. (1219 mm) |
| One side | 6 in. (152 mm) |
| Other sides | 12 in. (305 mm) |
| Between units | 24 in. (610 mm); 18 in. (457 mm) with no overhang within 12 ft |
| Roof mount height above roof | 6 in. (152 mm) |
| Shrubs/fences from coil | 18 in. (457 mm) |
Keep roof run-off and snow from falling on the unit.
Unit must be level within 2 degrees.
Models that show this code
12 models in KeepRite C4A3/CXA6 AC, KeepRite *SA/*SH Single-Stage Communicating, KeepRite *CA/*CH Two-Stage Communicating
Other codes on the same units
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Source: KeepRite/ICP C4A3/H4A3/T4A3/CXA6 Installation Instructions 421 01 5103 05, Table 1 Status Codes, p.17; KeepRite_ICP_KeepRite_Tempstar_Heil_split_A_C_HP_R_410A_R_22_service_421_08_5400_04.txt - section Table 13 Status Codes (single-stage); KeepRite_ICP_KeepRite_Tempstar_Heil_split_A_C_HP_R_410A_R_22_service_421_08_5400_04.txt - section Table 17 Troubleshooting (two-stage). 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.