valves and flow loss

[dirk_brijs]

what valves create the least flow loss?
Currently using true union valves or regular PVC valves but they all reduce the pipe size by about 40% or more creating (I think) allot of flow loss.
Any advise here.
Also regular true unions seem to reduce pipe size allot.

 

[sirreal63]

Upsize is the answer. If you are using 1" then go to 1-1/2" and use bushings or bell reducers to fit the 1" pipe.

 

[a.browning]

Something I have seen people do is upsize the piping, then put the valve, then downsize the piping again back to the normal diameter. This allows for a larger diameter for water flow inside the valve itself. Unions and such really cut back on size, I would be interested to see other's inputs.

 

[dirk_brijs]

what about knife gate valves?