[77newell]

Phil: this is a SWAG but if the leaky purge valve was not present prior to the 150PSI exposure and since you have demonstrated that neither the purge valve itself nor the governor are causing this by having changed them with no change in symptoms I would be suspecting something in the drier got distorted by the excessive pressure, probably where the active part of the purge valve seals to the housing. I would check if there is any interaction between the purge valve and the drier other than letting air out the vent. If there isn't then what I suggested above is all I could think of.