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Carrier · Mini-split

EC57 Refrigerant pipe sensor fault

Medium severity Carrier DLCM(R/H)B multi-zone outdoor

What the control is telling you

The refrigerant pipe temperature sensor reads out of range.

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

Likely causes

  • Sensor plug loose
  • Bad sensor
  • 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. Check the sensor plug on the board and the wire for damage.
  3. Unplug the sensor and measure its resistance. T1-T4 sensors read about 10 kOhm at 77 F (25 C); the discharge sensor (T5/TP) about 54.9 kOhm at 77 F. Compare with the sensor resistance tables.
  4. Out of range or open/shorted replace the sensor. Sensor reads fine: replace the board it plugs into.

Models that show this code

7 models in Carrier 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
  • EC71 Outdoor fan motor over-current
  • EC72 Outdoor fan motor phase loss

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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. 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.