NLP Fault Code 1003 - Direct Drive Troubleshooting (Public)

An NLP fault (fault 1003 on the touchscreen) stands for No Line Power. You will see this fault if the VFD detects insufficient voltage going to the drive relative to the drive rating.

To troubleshoot this fault:

1. Verify that the rated VFD input voltage matches what is being provided, including the number of phases.

2. Verify that the breaker to the fan is turned on and not damaged. Verify that the disconnect switch is assembled properly.

3. Verify that the wiring between the breaker and the VFD is a sufficient gauge and not damaged (the electrician can determine if the gauge is correct).

4. Verify that the disconnect switch on the control panel (if present) is turned on and not damaged.

5. Verify that the fuses are in place (if a fuse block is present) and are not damaged.

6. Verify that all wiring is properly landed into the top of the disconnect (if present), the bottom of the disconnect to the top of the fuse block (if present), and the bottom of the fuse block to the VFD.

7. Verify that the wires are landed on the proper input terminals L1, L2, and L3 (if 3PH).

If all of the wiring and the incoming power appear to be within spec, the issue may be with two ribbon cables inside of the VFD. To verify this:

1. Open the front face of the VFD by popping the 4 tabs shown in the video below (2 on each side). The wires inside are VERY short, so take care when opening the VFD to ensure that a wire is not accidentally unplugged. It is generally recommended to remove the VFD from the control panel enclosure to allow easier viewing and access.

2. Once the VFD is open, two ribbon cables should be visible inside of the VFD. If one is unplugged, plug it back in and snap the VFD back together, taking care not to accidentally unplug the internal cables again in the process.

If plugging the cable back in does not resolve the NLP fault, or if the cable was not unplugged, a replacement VFD will likely be necessary. Contact MacroAir Technical Support to assist with any replacement parts.