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Viessmann · Mini-split

EC72 Outdoor fan motor phase loss

High severity Viessmann Vitocal 200-S DLCM(R/H)B multi-zone outdoor

What the control is telling you

One phase of the outdoor DC fan output is missing.

Applies to: DLCMRBH / DLCMHBH multi-zone outdoor units 18-48K (Midea, Carrier, Viessmann Vitocal 200-S)

Likely causes

  • Loose fan lead
  • Bad fan motor winding
  • Bad outdoor PCB

Test and repair steps

  1. Safety kill power at the disconnect and wait for the inverter capacitors to discharge before touching boards or wiring.
  2. Restart after 2 minutes. If it clears, the unit is fine.
  3. Check the fan motor plug and leads.
  4. Check the three fan outputs for an obvious open.
  5. Measure the three fan windings. Unequal = replace the fan motor. Equal = replace the main PCB.

Models that show this code

7 models in Viessmann Vitocal 200-S DLCM(R/H)B multi-zone outdoor

DLCMHBH24CAKDLCMHBH30DAKDLCMHBH36DAKDLCMHBH48EAKDLCMRBH18BAKDLCMRBH36DAKDLCMRBH48EAK

Other codes on the same units

  • EC51 Outdoor EEPROM error
  • EC52 Condenser coil sensor (T3) fault
  • EC53 Outdoor ambient sensor (T4) fault
  • EC54 Discharge temperature sensor (TP/T5) fault
  • EC55 IPM temperature sensor fault
  • EC56 Indoor coil outlet sensor (T2B) fault
  • EC57 Refrigerant pipe sensor fault
  • EC71 Outdoor fan motor over-current

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Source: DLCMRBH/DLCMHBH Multi-Zone Outdoor Service Manual (sold as Midea, Carrier and Viessmann Vitocal 200-S; Viessmann doc 6225551-03, 12/2024), Table 23 Outdoor Unit Error Display p.26; diagnosis p.70. 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.