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Midea · Heat pump

EL01 Indoor/outdoor communication error

High severity Midea DLCURA ducted single-zone inverter heat pump (outdoor)

What the control is telling you

The outdoor unit is not communicating with the indoor unit.

Applies to: DLCURAH18-60 AAK/ABK single-zone heat pump outdoor units (18K-60K, regular and High Heat)

Likely causes

  • Loose or mis-wired control wiring between indoor and outdoor units
  • Incorrect 24 V thermostat wiring (R, C, Y1, Y2, B, W, D, L)
  • RS485 S1-S2 communication wiring fault (when used)
  • Wire touching tubing/moving parts or damaged
  • Indoor or outdoor board fault

Test and repair steps

  1. Warning: Turn off and lock out power at the outdoor disconnect and wait for the inverter capacitors to discharge before touching the outdoor board or compressor wiring.
  2. Check the indoor unit diagnostic display first.
  3. Verify interconnecting wiring at both terminal blocks matches the wiring diagram for the thermostat configuration used (Figs. 28-29).
  4. Tighten every terminal - the manual warns loose wiring causes overheating and malfunctions.
  5. If using non-polarity RS485 communication, check the S1-S2 wiring end to end for breaks or shorts.
  6. Make sure no control wire touches refrigerant tubing, the compressor or moving parts.
  7. If wiring is good, suspect the indoor or outdoor control board.

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Source: Midea/Carrier DLCURA Installation Instructions (Catalog DLCURA-03SI), Table 11 Outdoor Unit Diagnostic Codes, p.19. 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.