Irrigation Pump Runs But No Water at Valves—Master Valve or Pump Relay

System worked, then low pressure (half spray). Valve replaced, worked 1 day. Next day: pump runs, primed, valves have power, but no water/air at bleed screws. Two valve boxes only. Possible hidden master/backflow valve?

Two Main Causes

1. Pump/relay chain failed: Pump bad, OR relay bad, OR relay wire bad, OR controller not activating relay
2. Master valve failed: Auto valve before zone valves — if stuck closed, no water reaches zones. Located between pump and zone valves.

Diagnosis

• No water at bleed screws = no water reaching valves
• Check for master valve (wire on controller MV terminal?)
• Test pump relay: 24V at coil when zone active? 230V through contacts?

Master valve not on all systems. Check controller wiring.