Fireye NX6300 F42: Gas valve leak test failed during startup, what to check?
My burner control, a Fireye NX6300, is throwing an F42 fault during startup. It happens when the leak test runs, and the burner never gets to ignition. What should I check first?
The Fireye NX6300 F42 fault indicates that the gas valve leak test failed during the startup sequence (status 03-09). This means the controller detected an unexpected pressure behavior in the gas section between the safety shutoff valves. Potential causes include a leaking valve seat, unstable gas supply pressure, or incorrect test parameters.
Likely causes and checks
1Leaking valve seat (upstream or downstream)
- Points to it
- Gas is either escaping or entering the test section when it shouldn't, causing the pressure to decay or build up unexpectedly during the test.
- Check
- Observe if the fault consistently occurs at the same step. Have a qualified technician perform a tightness test on the gas safety shutoff valves according to the manufacturer's procedure.
2Low or unstable gas supply pressure
- Points to it
- The gas pressure in the test section is not within the expected range or fluctuates, interfering with the leak test's ability to accurately monitor pressure changes.
- Check
- Monitor the gas supply pressure during the leak test and compare it against the nominal pressure configured in the controller. Note if the fault occurs intermittently, especially when other gas-consuming equipment is active.
3Incorrect valve proving test parameters
- Points to it
- The controller's settings for the leak test, such as nominal pressure, test volume, or allowed leak rate, do not match the actual gas train configuration or operating conditions.
- Check
- Review the valve-proving option parameters (10.1 to 10.7) in the controller, especially if this is a new installation or if the gas train components have been changed. The test might also take an unusually long time if parameters are wrong.
Next check: First, observe if the F42 fault consistently occurs at the same step during startup or if it's intermittent. This can help differentiate between a persistent leak and a pressure issue. Then, check the gas supply pressure during the test against the nominal pressure set in the controller.
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