Inter-zone Bleed for Water Quality

[BernieH]

In order to avoid creating a dead end at a pressure zone boundary, I would like to install a connection between the higher zone and the lower zone. Rather than using a PRV that would close during times of low flow, I think people sometimes use a very small connection between the two zones. Could anyone tell me where I can find more information on this practice?
Thanks

 

[bimr]

Several firms make self contained pressure reducing valves. Here is an example:

http://www.controlvalves.com/series/127/127.html

 

[coloeng]

Is this the only feed to the lower pressure zone?

In our system we have some zones that are fed by more than one main and we use a setup where we have a prv in both mains with one of the mains being the main feed. The other main has a small diameter bypass around the prv to maintain some flow in that main. We sized the bypass so that the pressure loss in it with the low flow would match the pressure difference between the zones. The prv at this location is then set so that if the pressure in the lower zone drops a few pounds below what we want the pressure in the lower zone to be it will open. This provides additional water if there is a high demand such as a fire or other high use.

 

[greggy]

In our system we have the same situation: we bleed from the high to the low service to keep water moving in "pocket" areas. We make a connection between the two mains with 1 inch copper tubing with a curb stop valve for on-off control. The small diameter tubing runs continually a manageable amount of water (based on the difference of pressures in the two mains) that is not really wasted in the sense that it is not spilled out of the system, and solves a stagnation problem. In the event you don't need to keep the water circulating, close the stop.

 

[BernieH]

Thanks for the responses, they were helpful