Diagnosing Station 2 Failure After Solenoid and Diaphragm Replacement

After fixing Station 1, Station 2 now refuses to run unless you crack the bleed valve slightly—and even then, it shuts off when you close the bleed. You've already replaced the solenoid and diaphragm on Valve 2. Here's how to pinpoint the remaining issue.

Verify Solenoid Operation

1. Turn off water to the system.
2. Unscrew the solenoid from Valve 2.
3. At the controller, manually run Station 2 ("Run Single Station" mode).
4. Watch the solenoid plunger: it should pull up sharply into the coil.

If the plunger doesn't move: The wiring is faulty, the connection is reversed, or the controller isn't sending power. Check voltage at the controller terminals (22–26 VAC on Station 2 vs. Common).

If Solenoid Works, Recheck Diaphragm Installation

A diaphragm installed upside down, backwards, or with debris under the seat will cause exactly this symptom—water only flows when the bleed valve relieves pressure. Disassemble Valve 2 again, confirm the diaphragm orientation matches the manufacturer's diagram, and ensure the seating surface is clean.

Bleed Valve Leak Clue

Water leaking from under the bleed cap when fully open suggests the bleed stem or cap is damaged. Replace the bleed cap assembly if tightening doesn't stop the leak.

Start with the solenoid plunger test—it's the fastest way to isolate electrical vs. mechanical problems. Good luck!