If the downstream pressure increases after the burner stops, there may be regulator creep or a lock-up issue. The phenomenon is significant because it can lead to a high gas pressure alarm or trigger protection.
What is regulator creep?
With no or very low consumption, a small internal leak from the regulator seat can gradually increase the downstream pressure.
What is lock-up pressure?
It is the final pressure that stabilizes when there is no flow. It must be within the manufacturer's and installation's specified limits.
How it appears in diagnosis
Pressure is recorded immediately after shutdown and for a certain period. If it continues to rise, the regulator should be inspected.
Potential causes
Debris in the seat, seal wear, a pilot problem, or incorrect adjustment can cause the phenomenon.
Relationship with high pressure trip
If the high-pressure switch setpoint is close to the actual lock-up pressure, trips may occur after shutdown.
