Ok, this is a new one on me. I've got a 2400S on a new install (last one this year, I hope) that is acting stranger than any other I've ever seen before. When I pressured the main, it opened. That wouldn't be really unusual, except the bleed was tight and the solenoid and manual bleed collar were also snug. I opened the bleed collar thinking maybe some trash in the diaphram..........and the valve closed. It still drips (duh, with the bleed collar part open), I can't open the manual bleed collar enough to open the valve, but if I tighten it up the valve opens again. I can't think of any possible reason for this to work like this. If the exhaust tube was clogged, the valve wouldn't open. I took the bonnet off, checked the diaphram, bleed collar, solenoid.....everything I could think of looking for anything abnormal. I've got nothing but I'm hoping for some thoughts. Since it's a slip valve, I'm really hoping the body is OK. I didn't have a new valve with me to swap parts, and I can't get one until Monday. I'm putting a fork in this one tomorrow and if I can't figure it out, the tempation to winterize it and do the warranty work come spring looms on my horizon.