DURASTAR EL 01 Current Loop User Manual

Durastar Technical Resource Center
EL 01_Current Loop

Description

Communication error between indoor and outdoor unit.
Cause
The indoor unit does not receive feedback from the outdoor unit for 2 minutes, and this condition occurs four consecutive times.
Note: A DR SMART troubleshooting tool is highly recommended to troubleshoot this code. P/N DRPDRSMART. A voltmeter can be used as a guide, but results are not always guaranteed.
Solution

1. Verify the communication wiring at terminals 1, 2, and 3 on both the indoor and outdoor units. Wires must match terminal-to-terminal, be tight, undamaged, and have no splices.
2. If an external pump, float switch, or safety device is installed, confirm it is not breaking terminal 3. Terminal 3 is communication only.
3. Check incoming voltage at outdoor L1 and L2. Voltage must be between 187-253 VAC.
4. Check voltage at terminals 1 and 2. It should match L1 and L2 voltage. For R454B units, if there is no power at 1 or 2, check the fuses.
5. Set the meter to DC voltage. Place the red lead on terminal 2 and the black lead on terminal 3. A normal communication signal should pulse between +50 VDC and -50 VDC.
6. If the voltage stays positive and does not pulse, suspect the outdoor unit PCB.
7. If the voltage is fixed and near 0 VDC and does not pulse, suspect the indoor unit PCB or the communication wire between the units.
8. If the communication wire is suspected, run a temporary test wire between the indoor and outdoor units.
9. Before replacing a control board, inspect for pinched wiring or shorted components such as EEVs, thermistors, fan motors, or other components.