Fireye NX6300 F20 Drive Position Fault during modulation
I'm getting an F20 drive position fault on my Fireye NX6300 burner control system. It happens during modulation, and the actuator seems to be laboring. What should I check first?
An F20 drive position fault indicates that a fuel or air drive (servo or fan VSD) is not at its expected position according to the commissioned profile. This fault can occur during various stages of operation, including proving closed or purge positions, pre-purge, ignition, post-purge, or modulation. The specific subset number helps to diagnose whether the issue is mechanical, communication-related, or internal to the servo.
Likely causes and checks
1Linkage or damper binding
- Points to it
- If the fault occurs during purge or modulation, and the actuator labors or stalls, it strongly suggests a mechanical obstruction or issue with the linkage or damper.
- Check
- Disconnect the linkage and manually stroke the damper or valve (with the burner off and by qualified personnel) to check for any binding. Also, inspect couplings for signs of slipping.
2Fan VSD outside its error band
- Points to it
- If the fault occurs on the VSD drive during modulation, and the VSD is current-limiting or has a slow ramp, its error band might be exceeded.
- Check
- Verify the VSD ramp times and ensure that its internal PID control is disabled, as described in the inverter section of the manual.
3Stored close or purge position no longer reachable
- Points to it
- This cause is more likely if the fault occurs before the drives reach purge, especially after mechanical work or servo replacement, indicating the drive cannot achieve its programmed positions.
- Check
- The manual's troubleshooting table suggests checking feedback potentiometers and motor micro-switches, then resetting the close and purge positions in Commission Ratio mode.
4CANbus fault
- Points to it
- If ERR1 appears under the drive name and the display is slow or freezing, it points to a communication issue on the CANbus.
- Check
- Inspect the CANbus wiring, screens, and termination to the servo for any faults.
Next check: After checking for linkage binding, if the issue persists, note the drive number (F20 is drive 0) and its subset number to narrow down the problem further, as this will help differentiate between mechanical, communication, or internal servo faults.
Related questions
Describe the fault or upload a photo, and InduQT checks it against the manufacturer manuals. Share the result here when it helps someone else.