Pressure Switch or Check Valve Failure

Symptoms

• Pump never shuts off (runs continuously)
• Pump won't turn on at all
• Water flows backward through the system when the pump stops
• Pressure gauge fluctuates wildly

Diagnosis

A failed pressure switch can't read system pressure correctly, causing the pump to run continuously (stuck contacts) or not at all (open contacts). A failed check valve lets water flow backward, dropping pressure and causing cycling.

Step-by-Step Repair

1. 1

   Turn off the pump breaker for safety.

2. 2

   Remove the pressure switch cover. Inspect the contact points — look for pitting, burning, or corrosion.

3. 3

   If contacts are pitted or burned, replace the entire switch (they're inexpensive).

4. 4

   If the pump runs continuously, the cut-off pressure may be set higher than the pump can achieve. Adjust the nut on the large spring to lower the cut-off setting.

5. 5

   For check valve issues: install or replace the check valve on the discharge side of the pump. Make sure the arrow on the valve body points in the direction of flow (away from the pump).

6. 6

   After replacing either component, start the pump and verify proper operation through several on/off cycles.