Boiler Pressure Change on Class J's

[NW Mailing List]

Is there a record of when the BP of Class J's 600-610 was raised from 275 psi to 300 psi?  I've always used  "after 8/45" because of the 275/300 comparison tests run during that month.  I may need to be more specific so I'm looking for better info.

Dave Stephenson