Oil pressure issue Howden WRV255, stumped again

[RANGER1]

When I first started out in Kvaerner, we used the Kral MFUG-55 screw pump, it would run for twice the hours of the compressors without needing any service, only the vertical ones needed shaft seals replaces every now and then, because the operators didn't drain the gas that collected on top with the shaft seal after a long stand still (they even had a purge screw )

Tycho,
Viking is a good pump with all the information for sizing etc on link I posted.
It can plot pump output with different differential pressures, oil viscosity, speed etc.
If you had motor amps & motor size we could pinpoint model.
Could be AS or AK4195.
If you change differential pressures or viscosity, it shows pump output changes to see what's going on.
Maag pump probably cheap & sized borderline.
I do not have Howden programme at the moment, but Mycom 250S M or L requires 200l/min under your conditions.
I know Howden require probably 20% more than Mycom due to monster clearances & agricultural design
I bet Viking pump is bigger.
My guess is compressor oil pump should be 5 l/second to be good for all situations, even if shipped to Australia.
That does not help you much, but sometimes it helps to know if pump was sized correctly, as if compressor wears a bit & certain conditions like maximum load & differential pressure across machine mean unreliable.
You could pull out suction filter to pump & see like you have previously, as not much to lose.
Made gauges of transducers reading accurately.