Bypass valve

[Tonygeek]

Thanks again John. I have a BS4613 dial-type tyre pressure gauge, which is marked in 0.1 bar steps, so I used this (at the top of my rig to avoid getting water into it!). The water supply was from the mains via a good length of hosepipe and I had the valve discharging into a large bucket. A bit Heath Robinson and messy but I was able to control the pressure and flow by carefully opening the mains tap a little. I would say that the flows I was getting through the valve when it should have been shut were less than 5 l/min. I would need to spend time improving the set up in order to have any free hands to take measurements etc!

I am toying with the idea of trying to lap in the valve jumper to its seat with a little fine valve grinding compound as one used to with car engine valves. I am surprised they don’t use something a bit more resilient than the hard plastic for the valve jumper, which would have a better chance of giving a seal. Maybe they are not worried about something less than a complete seal?

 

[Johntheo5]

They shouldn't pass anything if shut, not even 0.2LPM, what's the point otherwise?, you may as well have that gate valve suggested above.

 

[Tonygeek]

I completely agree, John, but this is what I am faced with - both the new valve and the old one. Building regs require an automatic bypass and not a fixed one. Surely one that works is not asking too much of modern science?!