ace pipe blown twice in a row

Hi my ace pipe went bang the other day, the flexi pipe just off the pressure side of the pump, I changed the pipe and after idling for a minute it went bang in the same place, i removed the pump and fitted the conversion just so I can use the car, any ideas, is there a presume relief valve, last week I did a test on haukeye and it showed valve 2 a little slow, it was on the limit on time, cheers phil