Jeffrey Williams wrote:- > I think it was a Heisler I saw that seemed to "pop" realistically"
Thank you for the compliment. The Heisler SVs are what I describe as "semi-pop", in that they are not as scary as a proper pop valve and drop about 5-10psi before re-seating. They have a tendency to "feather", which is a little wasteful on steam, but which some owners like because it adds atmosphere. I shall not be making any more of this type of safety valve for at least a year. Mike
