Zurn Pex B has some issues. The manufacturing process has manufacturing defects from time to time and the pipe must be examined before it is installed in the walls of any home. That being said I prefer Zurn Pex B over Uponor Pex A. Uponor Pex A is failing in San Diego, San Clemente, Mission Viejo, Lagunia Nigual, Orange County, Aliso Viejo, Newport Coast. Los Angeles, Irvine.