The CFW800 shows ready but the motor will not start when commanded, or it faults immediately on a start attempt with no rotation.
Here are the most common failure paths on the WEG CFW800 when not starting is the reported condition. Frequency reflects real field reports; First Check is the remote step to take before sending us your logs.
| Cause | Likelihood | First Check |
|---|---|---|
| Run/enable signal or safety chain not made | High | Check the enable, run and safety-input wiring and the terminal states on the HMI |
| Wrong control source or reference (panel vs comms vs terminal) | Medium | Confirm the command and reference source parameters match how you are starting it |
| Parameter lock or a faulted state not cleared | Medium | Read the active fault list and whether a prior fault is still latched |
| Motor overload or trip threshold set too low | Low — Medium | Check the thermal setting and the motor nameplate current |
Work through these in order. Each step is something you can perform and report back on without opening the enclosure or swapping parts.
Note whether the drive shows READY, a latched fault, or no run command. The display state decides whether we correct a signal or clear a fault.
Check the enable, run and safety-chain inputs on the terminal/HMI. An open safety contact or a missing enable is the most common 'ready but no start' cause.
Open the command and reference source parameters. If they point to comms but you are pressing the panel start, the drive ignores the command — we align them.
Read the fault list and clear any prior fault that is still active. A latched thermal or comms fault blocks a new start until reset.
After the signals and sources are correct, jog at low speed. Rotation confirms the drive and motor are fine; no rotation means we re-check the enable path.
A CFW800 that is ready but will not start is almost always a missing enable/safety signal or a wrong control source, not a failed drive. The display state and the terminal check localize it fast. Cross-reference the broader collections: Will not start · VFD & motor control.
Rarely. A ready-but-no-start is a signal or source issue we resolve remotely. We only suspect hardware if the enable path is proven good and it still will not run.
READY means power and no fault — not that a run command is present. The enable and control source must also be made, and we check those.
If it jogs, the motor is fine. No jog with a proven enable points back to the drive, and we confirm that before any swap.
Send us the error code, a photo of the screen and what you already tried — an independent specialist reviews your case and replies with an evaluation, typically within 24 hours.
Submit Your CaseShare the display state and the enable wiring. We align signals and control source remotely so you avoid swapping a good drive.
Submit Your Case Connect With SpecialistsWe do not perform hardware repair, we do not replace parts, and we cannot promise a 100% resolution. Our role is limited to remote diagnostic and step-by-step guidance based on the information, photos and logs you share.
Before changing drive parameters or replacing parts, verify against the official documentation from WEG:
Tip: for simple issues, a general-purpose AI assistant can help you interpret a fault code — but always cross-check any corrective action against the official manual before applying it.
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Full pumps, motors & drives troubleshooting collection.