I'm trying to understand how our Sherwood regulators (four in the family now) work. Or rather, how the features work that make Sherwoods unique. I took two regulators in to the LDS for service today -- a 1985-vintage SRB2100 Brut that we've been using occasionally, and a newer SRB7100 Brut that I just bought used. I asked the service guy about the dry-air bleed system, and what happens when it malfunctions -- I'd heard that breathing becomes very difficult. He said it wasn't a problem; that the dry-air bleed system is what makes Sherwood regulators balanced, and all that would happen if it malfunctioned is the reg would act like an unbalanced one. Hmmm... I told him I thought the dry-air bleed system was to keep water out of the ambient-pressure part of the first stage. Besides, Bruts had the dry-air bleed system too, but weren't balanced. He stuck to his story. I must say that he seemed pretty knowledgeable about Sherwood regulators in general... He knew the SRB2100 had originally come with a crimped-on piston seat that wasn't replaceable, but that the original piston would have been replaced with a replaceable-seat piston if a service had been done since the early 1990s. He also knew about the flow restrictor, and that the SRB2100 Brut didn't have one -- the air for the dry-air bleed system moved through the piston. So... Does the dry-air bleed system have anything to do with a regulator being balanced?