Green Guru LLC Irrigation & Landscape Lighting

Drain-Back Diagnostics

Lake Pump Check Valve

Drain-back symptoms are often check-valve failures, not just pump wear. Pressure-hold diagnostics reduce trial-and-error repairs.

This guide uses shutdown and restart behavior to confirm the right repair path.

Drain-back detection Pressure-hold checks Startup lag diagnostics Service-scoped correction

Quick Answer: Why does pressure drop after shutdown?

Drain-back is common. Check-valve sealing issues can let water fall back and create unstable restarts.

Generic Pump Servicing vs. Drain-Back Diagnostics

Generic Pump Servicing Check-Valve Diagnostics
Address pump onlyValidate pressure hold and check-valve sealing first
Restart lag may continueRestart performance verified after targeted repair
Drain-back not measuredPost-shutdown pressure behavior documented
Higher callback riskRoot cause isolated before parts swaps

When this is likely your issue

  • Pressure falls rapidly after shutdown.
  • Restart lag appears repeatedly.
  • Prime and pressure stability vary day-to-day.
  • Prior service did not stop drain-back symptoms.

What we check before replacement

  • Pressure hold behavior after stop events.
  • Check-valve seal and leakback indicators.
  • Interaction with foot valve and intake path.
  • Restart response after correction.

Deployment workflow

  • 1

    Measure post-shutdown pressure behavior

    Capture how quickly pressure drops after stop cycles.

  • 2

    Inspect check-valve path

    Evaluate check-valve and adjacent components for leakback contributors.

  • 3

    Apply targeted correction

    Repair or replace check-valve path where diagnostics confirm drain-back failure.

  • 4

    Validate restart stability

    Confirm reduced lag and improved pressure hold in repeat cycles.

Related guides

FAQs

What does a pump check valve control?

It helps maintain one-way flow and reduce drain-back after shutdown.

Can check-valve issues cause startup lag?

Yes. Drain-back can force re-stabilization on restart, causing lag.

How is drain-back identified?

By monitoring post-shutdown pressure drop and repeated restart behavior.

Should foot valve and check valve be reviewed together?

Yes. Both can contribute to prime and pressure instability.

Can this be mistaken for pressure-switch problems?

Yes. Symptoms overlap, so control-side checks are included.

Does replacing the check valve always solve it?

Not always. Intake integrity and control settings are also validated.

Is this mainly a startup-season issue?

It is common at startup but can appear whenever drain-back worsens.

Is this a retail-fit guarantee page?

No. It is a service-first diagnostic reference with field confirmation.

At a glance

Check valve diagnostics facts
IndustryPump-fed irrigation
ComponentPump-system check valve
Primary symptomDrain-back and startup lag
Key checksPressure hold, leakback behavior, restart stability
Service noteCheck-valve decisions are made with intake and control context

Need it diagnosed?

We confirm drain-back causes before recommending check-valve replacement.

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Related: Pump systems hub