Fireye NX6100 F14 Status 07: main air pressure not proven, fan runs, what to check?
I'm getting an F14 Status 07 fault on our Fireye NX6100. The main combustion air pressure isn't proving, but the fan seems to be running. What should I check first?
The Fireye NX6100 integrated burner controller reports an F14 fault when the main combustion air pressure switch fails to register air pressure at a required point in the sequence. Status 07 specifically indicates this occurred during the proving purge positions, after the air pressure prove time t1. This means the controller expects to see air pressure but doesn't, even though the fan may be operating.
Likely causes and checks
1Fan not running or slow
- Points to it
- Even if the fan appears to be running, it might not be at the required purge speed, or there could be an issue with the motor output, starter, or VSD signal preventing it from reaching full speed.
- Check
- Confirm the burner motor output, starter, and any VSD run signal are active and verify the fan reaches the necessary purge speed.
2Air path restricted
- Points to it
- A restriction in the combustion air path can prevent sufficient pressure from reaching the switch, even with the fan running. This often manifests gradually.
- Check
- Inspect the air intake, the fan wheel for debris, the damper travel for full opening, and the flue for any obstructions.
3Switch setpoint too close to low-fire differential
- Points to it
- While Status 07 points to an initial proving issue, if the fault occurs later (Status 15-16) or if the system struggles to maintain pressure, the switch setpoint might be too sensitive for the actual air differential, especially at lower firing rates.
- Check
- Measure the differential pressure at the switch across the firing range and compare it against the switch's setpoint.
Next check: Start by verifying the fan's actual speed during the purge cycle and ensure all components in the fan's electrical path (motor output, starter, VSD) are functioning correctly. Then, visually inspect the entire combustion air path for any obvious restrictions.
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