HVACopediaGoodman · Air handler
EC1 Communication error with the outdoor unit
What the control is telling you
The air handler lost communication with the outdoor unit; the outdoor unit does not run.
Applies to: ComfortBridge communicating air handlers AVPTC**14 (B* revision board) and MBVC1201/1601/2001 modular blowers
Likely causes
- Wrong or poor low-voltage/communication wiring between indoor and outdoor units
- Outdoor control lost power while running
Test and repair steps
- Warning: Turn off power to the air handler before working on wiring or the blower.
- Check the 1, 2, R, C wiring between the units: correct terminals, one wire per terminal, tight connections, no shorts or breaks.
- Find out why the outdoor control lost power (breaker, disconnect, fuse).
- Press the learn button (about 2 seconds) or use the Lrn menu to restart communications.
Models that show this code
21 models in Goodman/Amana ComfortBridge AVPTC/MBVC
Other codes on the same units
- Eb4 Blower motor lost rotor control or high current
- Eb5 Blower motor failed to start 10 times
- Eb6 Blower shut down for voltage or power module temperature
- Eb7 Blower motor missing shared data / failed to start 40 times
- Eb9 Airflow lower than demanded
- Ed0 No shared data on the network
- Ed1 Invalid shared data
- Ed4 Shared data rejected by the control
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Source: Goodman ComfortNet ASXC/GSXC/DSXC, ASZC/GSZC/DSZC, AVPTC/MBVC service manual, Air Handler Troubleshooting Matrix (B*) p.59-60. Summarized in our own words; check the original manual for your model.
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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.