Grinder pump running constantly
Short answer
A grinder pump should run in short cycles and stop. If it runs nonstop, stop using water, check for a running toilet or dripping fixture, and request service; do not switch the pump off. Causes: a hung or failed float, the selector in Hand, air lock, a clogged grinder or check valve, or too much inflow.
A grinder pump constantly running is either being told to run by a level control that will not release, or is running without moving enough water to reach its shut-off point. Every manufacturer table says the same thing in different words: a float hung up or failed, the selector switch in Hand, air lock, a clog or closed valve, or more water coming in than the pump can push out.
A normal grinder pump runs for a short burst and stops. If you can hear yours humming for minutes on end, or the run light never goes out, read on.
Safe steps, in order
Nothing here opens the panel or the basin. If a step does not clear it, stop and make the call.
Step 1: Confirm it really is running
Keen panels show an amber pump-run light, Myers a yellow one, E-One Sentry a Pump Running light. Listen near the lid for a continuous hum. Note how long it has been going.
Step 2: Stop using water and look for water you did not know you were using
A toilet flapper that leaks, a tub spout that drips, a humidifier or softener draining, irrigation tied into a drain: all of these keep a basin filling. Keen, Liberty and Barnes each list leaking fixtures or excessive inflow. Lift each toilet tank lid and listen; that is the whole homeowner inspection.
Step 3: Do not turn the pump off
It is tempting to cut the breaker to save the motor. E-One asks owners not to disconnect power to the unit, and a pump that is running at least has a chance of keeping the level down. Leave the panel alone.
Step 4: Request service
A pump that will not shut off is a same-week repair even when nothing is backing up. On BCSS or Gulf Shores Utilities, their first-call rules apply only once the alarm light is on; a constantly running pump without an alarm can go straight to a plumber.
Likely causes, in order
Combined from the Keen, Myers, Liberty and Barnes tables for a pump that will not turn off.
- A float that is defective, restricted, hung up on the basin or held by debris (Keen, Liberty, Barnes). The Off float never drops, so the pump never gets its stop signal.
- The Hand-Off-Auto switch left in Hand (Keen, Myers, Liberty, Barnes). The pump is being commanded to run regardless of level. A technician switches it back; it is inside the enclosure.
- Air lock. The pump runs but moves little or no water, so the level never falls (Keen, Myers, Barnes).
- A partially clogged grinder, a clogged check valve, or a closed gate or street valve (Myers). The pump runs against a restriction and cannot lower the level.
- Excessive inflow: leaking fixtures, ground water entering the basin, or a house that outgrew its pump (Keen, Barnes).
- Total head beyond the pump's capability (Liberty), typically after a pump of the wrong model was installed, or where the pressure in the street main has risen.
- A failed panel or contactor that stays closed (Liberty, Keen).
How often should a grinder pump run?
There is no fixed number, because the pump starts whenever the basin reaches its On level and stops at its Off level; a household's water use sets the count. The manufacturers set limits from the other direction. Liberty's duplex float instructions say to set the On and Off differential so the pump does not exceed 12 starts per hour. Goulds says to check the operating range for a run time of at least two minutes. E-One's level control is a differential pressure switch rather than floats, with the same purpose: a few minutes of running, then rest.
So a pump that cycles briefly a handful of times a day is normal. A pump that runs for ten minutes without stopping, or starts every two or three minutes, is not.
Brand specifics
Myers: a yellow run light that stays on has a short list: Hand mode, a failed level control, a partially clogged grinder, a clogged check valve or closed valve, or air lock.
Keen: a pump that will not shut off is a defective or restricted float, the switch in Hand, air lock or excessive inflow. The panel manual adds a failed contactor, and notes that chattering contactors come from failing floats or floats in turbulence.
Liberty: runs but will not turn off is the selector in Hand, a float hung on the basin, or a failed panel or float. Liberty also lists the discharge blocked and a check valve stuck or backwards under the same heading, because a pump that cannot discharge keeps running.
Barnes: a float restricted, excessive inflow, air lock, or Hand mode.
What we check
Float position, tether and movement, and grease on the stems; the selector switch position and contactor; running current (a pump running against a closed valve or clog draws differently from one running on air); the check valve and discharge valves; the basin level while the pump runs, which separates air lock and restriction from inflow; fixture leaks with a meter test; and whether ground water is entering the basin.
After heavy rain
If the pump only runs constantly during storms, the basin is probably taking on ground water. The pump may be fine. The lid seal, inlet joint and tank are where the fix lives.
Still not right? Ask from here
Your name, a way to reach you and what the pump is doing. That is all we need to start. Town and utility are optional.
Sewage backing up or overflowing? Stop using water and call now: (251) 850-8031. On a utility-owned pump, call your utility first.
Questions people ask
Why does my grinder pump keep running?
Most often a float that is stuck or has failed, so the pump never gets the signal to stop. Next: the selector switch left in Hand, air lock, a clog or closed valve the pump cannot push past, or more water entering than it can move. Service sorts out which; none of it is a homeowner repair.
Is it bad for a grinder pump to run continuously?
Yes. The manufacturers size cycles in minutes, not hours, and they treat an overload that trips after a long run as a sign of damage. A pump that cannot stop is also usually a pump that cannot lower the level, which is how backups start.
My grinder pump is not shutting off but the alarm is not on. Is that still a problem?
Yes. The level may be sitting between the Off and Alarm points, so the alarm never trips while the pump runs flat out. Request service before the next heavy-use evening pushes it over the alarm level.
Can I just turn it off until the plumber arrives?
E-One asks owners not to disconnect power to the unit. A running pump is doing some work; a pump that is off is doing none, and your storage starts counting down. Leave it on, cut your water use, and get the visit booked.
Sources and facts
- Keen O&M p.9 and control panel O&M p.4: won't shut off: defective or restricted float, H-O-A in HAND, air lock, excessive inflow; panel: H-O-A in HAND, failed floats, floats hung up, failed contactor, air lock; chattering contactors from failing floats or floats in turbulence. Keen Pump O&M-KPCG (May 2022), keenpump.com/…; Keen Pump General O&M, Control Panel, keenpump.com/… (read 2026-11-04)
- Myers manual p.9: yellow run light stays on: H-O-A in Hand, failed level control, partially clogged grinder, clogged check valve or closed gate/street valve, air lock. Pentair Myers WG(X)20 owner's manual 23833A744, www.pentair.com/… (read 2026-11-04)
- Liberty PRG manual p.10: runs but won't turn off / doesn't pump: selector in Hand; float hung on basin; failed panel or float; discharge blocked; check valve stuck or backwards; valve closed; total head beyond pump capability. P.11: cycles or runs with no fixtures in use: basin too small, leaking check valve, improper float setting, leaking fixtures. P.6: duplex ON/OFF float differential set to not exceed 12 starts per hour. Liberty Pumps ProVore PRG-Series installation manual 2399000, www.libertypumps.com/… (read 2026-11-04)
- Barnes OGV manual p.12: won't turn off: float restricted, excessive inflow, airlock, H-O-A in HAND; cycles too often: check valve, leaking fixtures, ground water entering basin. Barnes OGVF/OGVH installation manual (Form 108890 Rev X), d1pkofokfruj4.cloudfront.net/… (read 2026-11-04)
- Goulds IM038 p.5: check operating range for a minimum two-minute run time; pumps that run but do not pump are probably air locked. Goulds Water Technology IM038R08 grinder pump manual, www.xylem.com/… (read 2026-11-04)
- E-One Product Family brochure p.2: differential pressure switch level control. E-One user instructions p.15: do not disconnect power to the unit. E/One Product Family brochure (LM000365 Rev D), eone.com/…; E/One DH071 Installation Instructions incl. User Instructions (NA0061P01 Rev H), eone.com/… (read 2026-11-04)
- E-One Sentry brochure p.1: Pump Running indicator. E/One Sentry Alarm Panels brochure (LM000323 Rev H), eone.com/… (read 2026-11-04)