HVACopediaCarrier · Mini-split
EH02 Zero-crossing signal error
What the control is telling you
The indoor board does not see the AC zero-crossing signal (none for 4 minutes or the timing is off).
Applies to: DLFSHBH high wall indoor units 09-24K (Midea / Carrier / Viessmann) on DLC multi-zone or single-zone outdoor units
Likely causes
- Wiring / supply problem
- Bad indoor PCB
Test and repair steps
- Safety kill power at the disconnect and wait for the inverter capacitors to discharge before touching boards or wiring.
- Check the power wiring and supply voltage. Fix and restart.
- If supply and wiring are good, replace the indoor main PCB.
Models that show this code
5 models in Carrier DLFSHB high wall indoor
Other codes on the same units
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Source: Carrier MS-DLFSHB-01 High Wall Ductless Service Manual (04/2021), Table 9 p.17; DLCMRBH/DLCMHBH Multi-Zone Outdoor Service Manual (sold as Midea, Carrier and Viessmann Vitocal 200-S; Viessmann doc 6225551-03, 12/2024) p.37. 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.