My suspicion is that Appions are failing due to not having a really good filter/dryer on the inlet.
Filter/ dryers are filled with molecular sieve to catch water and should catch a lot of contaminants. But they also have a lifespan and need to be changed regularly. If left open to atmosphere they'll absorb water and be less effective.
Without a dryer tiny particles of resin will get into the comp. pistons and stick to the piston rings eventually causing failure.
Excessive running under vacuum isn't good, but probably not the root cause.
RB
Filter/ dryers are filled with molecular sieve to catch water and should catch a lot of contaminants. But they also have a lifespan and need to be changed regularly. If left open to atmosphere they'll absorb water and be less effective.
Without a dryer tiny particles of resin will get into the comp. pistons and stick to the piston rings eventually causing failure.
Excessive running under vacuum isn't good, but probably not the root cause.
RB