I've been testing my Stuart D10 engine with a flash boiler. There is no regulator / throttle valve between the boiler and engine, since the speed control is by modulating the gas valve and electric feed pump speed, and hence no pressure drop.
The engine ticks over at 6.5psi (lightly loaded) and under heavy load conditions the pressure can rise to a steady 38psi at 300RPM.
Conventional boilers for the D10 run at 60psi setting, but does anybody know the throttle valve pressure drop on their conventional systems and do you ever run the engine at full boiler pressure.?
I've never done any pressure testing at the engine, but my stationary boilers usually run at 50 psi. Never had the need to go anywhere near full pressure to run 'em, just 'cracking' the control valve is normally enough.
So why do I have 50 psi in there? 'cos it's not unusual for me to be running 4 or 5 engines at a time - 6 is a pinch, but can be done with care.