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Fix an ejector pump that will not run

We'll confirm power, check the float, inspect for blockages, then tell you when to call a plumber.

Troubleshooting · Home maintenance
15–30 min
What you'll need
  • Flashlight
  • Access to circuit breaker
Step 1 of 8

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Steps

Goal: Confirm power, check the float, inspect for blockages, then fix or call a plumber.

  • Listen at the ejector pump basin when wastewater should be pumping. If you hear nothing, the pump is not starting. If you hear a hum but no pumping, the impeller may be jammed.
  • Good: Pump runs—different issue. Bad: Pump silent or hums—proceed to Check power.

Check power

Goal: Confirm the circuit breaker is on.

  • Locate the circuit breaker for the ejector pump. Reset if tripped. When it trips again immediately, there may be a short—call a plumber.
  • Good: Breaker on. Proceed to Check float.
  • Bad: Breaker trips—call a plumber.

Check float

Goal: Confirm the float switch triggers the pump.

  • The float switch turns the pump on when the basin level rises. Gently move the float up to see if the pump starts. Do not reach into the basin—gas and bacteria are present.
  • Good: Pump runs when float raised—float was stuck. Clear debris and test again.
  • Bad: Pump does not run—check for blockages or use manual override.

When to get help

Call a plumber if:

  • The breaker keeps tripping.
  • The pump hums but does not run (jammed impeller).
  • The float is stuck or inaccessible.
  • You need to replace the pump.
  • You are not comfortable with electrical or pump work.

Do not reach into the basin.

Verification

  • Pump runs when the basin fills.
  • No overflow or backup from the pit.
  • Float moves freely and triggers the pump.
  • Breaker stays on.

Escalation ladder

Work from the device outward. Stop when the problem is fixed.

  1. Check power Reset circuit breaker; confirm power to pump.
  2. Check float Float stuck low prevents pump from starting—move float to test.
  3. Check blockages Debris can jam the impeller—inspect intake and discharge.
  4. Manual test Use manual override to test if pump runs.
  5. Call a plumber Breaker trips, pump hums but does not run, or pump replacement needed.

What to capture if you need help

Before calling support or posting for help, have these ready. It speeds everything up.

  • Breaker status
  • Float position and whether pump runs when raised
  • Whether pump hums or is silent
  • Manual override result

Does the pump run when the basin fills?

The pump should run when the float rises.

Listen at the ejector pit when wastewater should be pumping. Runs: pump is working—different issue. Silent or hums: pump not running—check power and float.

Yes No

You can change your answer later.

Is the circuit breaker on?

A tripped breaker cuts power to the pump.

Check the circuit breaker for the ejector pump. Reset if tripped. On: proceed to float. Trips again: possible short—call a plumber.

Yes No

You can change your answer later.

Does the pump run when you raise the float?

A stuck float prevents the pump from starting.

Gently move the float switch up. Do not reach into the basin. Runs: float was stuck—check why it stuck. Does not run: pump or wiring issue.

Yes No

You can change your answer later.

Float was stuck

Clear debris or adjust the float so it moves freely. Test again. If it sticks again, call a plumber.

Done

Does the pump hum but not pump?

A hum with no flow suggests a jammed impeller.

If the pump hums but does not move water, the impeller may be jammed. Shut off power. Check for blockages. If you cannot clear safely, call a plumber.

Yes No (silent)

You can change your answer later.

Does the pump run in manual mode?

Manual override bypasses the float.

Use the manual override or test button if present. Runs: float or wiring issue—call a plumber. Does not run: pump or motor failed—call a plumber.
Question

Does manual mode run the pump?

Continue

You can change your answer later.

Pump is running

The ejector pump is working. If the problem returns, check the float and discharge line.

Done

Call a plumber

Call if: breaker trips, pump hums but does not run, float is stuck or inaccessible, or you need to replace the pump. Do not reach into the basin.

Done

Reviewed by Blackbox Atlas

Frequently asked questions

What is an ejector pump?
A pump that moves wastewater from a basement bathroom or laundry to the main sewer line. Used when fixtures are below the sewer level. Similar to a sump pump but for sewage.
Why would an ejector pump not run?
Power loss, tripped breaker, stuck or failed float switch, jammed impeller, or clogged discharge. The float tells the pump when to run; if it is stuck low, the pump never starts.
Can I fix an ejector pump myself?
You can check the breaker and float. Pump replacement and electrical work often require a plumber. Do not reach into the basin—gas and bacteria are present.
When should I call a plumber?
Call if: the breaker keeps tripping, the pump hums but does not run, the float is stuck or inaccessible, or you need to replace the pump. Do not reach into the basin.

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