Van's response
We?ve seen/heard of this several times.
It?s more likely when the engine is warm and the fuel tank not full. 2.2 lb seems high as the minimum pressure. Lycoming carbs min pressure is 0.5psi. As you see, the Rotax will run happily at <2.2psi, and typically the pressure will not drop much <2psi. Climbing is the worst case scenario as the engine is now higher than the tank and the fuel demand is greatest (high flow = lower pressure).
My guess is that individual installations/conditions vary and can cause this. You?ve got different pumps, sensors, differing types of fuel, amounts of fuel, tank venting, climb angle, temperature (OAT and fuel/engine temps), even variable resistance/voltage to the sender ? the list goes on. If the alarms are a concern, setting the value to say 1.8psi will probably eliminate most of them while still preserving the feature if the fp does drop enough to stop the engine.
Vans