We are running 2 aircraft with the new -40 bypass switch on the #2 PCM with over 50 hours no bypass. I was told by the tech rep there is 3 problems with the system.
1. The flow rate when the landing gear is cycled sets up a PSID near to the bypass condition of the older dash switches too strong of a spring and the bypass switch would not work.
2. The chafing of the filter in the bowl helps in clogging the filter which again increases the chance of the PSID occuring. So you end up changing a filter when it won't stop poping.
3. Air in the system will cause a bypass however this will only happen after the system has been serviced if you have about 5 hours on the aircraft after servicing the system and have a bypass it is not air in the system.
The fix so I'm told new -40 switch which seem to be working, new type of filter with a loose rivet to allow the filter to spin and the base to remain solid to stop chaffing. I think they may change to micron rating as well. The filters I was told will be out next year.
