What a Master Valve Does

A master valve sits upstream of zone valves and closes whenever no station runs. It can stop catastrophic leaks downstream if the controller commands it closed.

When to Add One

Sloped sites, high static pressure, and systems with history of stuck zone valves benefit most. Pair with flow sensing for alarms.

Placement and Sizing

Size for full-system GPM and place where you can service without flooding the yard.

Controller Wiring

Dedicate a terminal or module output per manufacturer guidance—do not share commons incorrectly.

Frequently Asked Questions

Does a master valve hurt pressure?

It adds minor loss—size accordingly.

Can I retrofit?

Yes if trench access and electrical capacity allow.