Low Pressure in Auto Mode Only: Richdel Valve Diaphragm Replacement

Auto Run = Low Pressure; Manual Valve = Full Pressure

When manual valve operation yields full pressure but automatic operation doesn’t, the valve diaphragms are worn. The solenoid lifts the plunger, but the diaphragm can’t seal under automatic cycling.

Fix

1. Replace the diaphragm on one valve first.
2. Test that zone in auto—if pressure restores, replace diaphragms on the remaining valves.

Wiring or solenoid faults would prevent the valve from opening at all.