The pressure release valve has been changed. Why is it still dripping? Is it the expansion vesel?

archie, March 2013

Reduce pressure to 1.2 bar,it should not leak if it's new ,you have to return to seller it still leak,if from 1.2 bar when boiler is on full blast for 6 hrs or more it's should stay 1.3 bar if keep rising than it's expansion vessel need air pump in to .75 bar to do it with cycle pump ,with boiler drain out

ltd, March 2013