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Fix a hot tub that will not circulate

We'll confirm the symptom, rule out power and air lock, then isolate the cause—clogged filter, pump impeller, or circulation pump—or tell you when to call a pro.

Troubleshooting · Home appliances
15–45 min
What you'll need
  • Screwdriver or wrench (for pump union)
  • Filter cleaner or hose (optional)
  • Replacement filter (if damaged)
Diagnostic graph validation issues: Terminal node n_pump_runs must have null branches; Terminal node n_air_lock must have null branches
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Steps

Goal: Confirm the symptom, rule out power and air lock, then isolate the cause—filter, pump, or suction.

  • Turn on the hot tub jets. Check if the pump runs and if water moves visibly.
  • Good: Pump runs and water moves—circulation works.
  • Bad: Pump runs but water does not move, or pump does not run. If the pump hums but does not turn, shut off power immediately—do not let it run. See When to get help.

Check power

Goal: Rule out power loss and GFCI before opening the hot tub.

  • Verify the hot tub is plugged in or the breaker is on. Hot tubs use a GFCI—check the outlet or subpanel for a tripped GFCI. Press the reset button if tripped.
  • If the breaker trips immediately when you turn on the pump, do not reset repeatedly—call a pro.
  • Good: Power is on and GFCI is reset. Proceed to Purge air lock.
  • Bad: Breaker keeps tripping—call a pro.

Purge air lock

Goal: Remove air trapped in the pump so water can circulate.

  • With the pump off, loosen the union at the pump inlet (one turn—do not remove). Turn on the pump briefly; water and air will purge. Tighten the union when water flows.
  • Some pumps have an air bleeder valve—open it, run the pump, close when water flows.
  • Good: Water flows and circulation returns. The air lock was the cause.
  • Bad: Still no circulation—proceed to Filter and suction.

Filter and suction

Goal: Check the filter and suction for blockage that restricts flow.

  • Turn off power. Remove the filter cartridge and inspect for debris, scale, or damage. Rinse with a hose or soak in filter cleaner if dirty. Replace if torn or damaged.
  • Confirm the skimmer and main drain are not covered by debris. Check suction covers for clogs.
  • Good: Filter is clean and suction is clear. Reinstall and test. If still no circulation, the pump or impeller may need repair—call a pro.
  • Bad: Filter is severely clogged or damaged—clean or replace, then test.

When to get help

Call a pro if:

  • The pump hums but does not turn (seized impeller or motor).
  • You smell burning.
  • The breaker trips immediately when you turn on the pump.
  • You are not comfortable with electrical or plumbing work.

Pump replacement requires draining and plumbing. Never work on electrical components with wet hands or while standing in water.

Verification

  • The pump runs and water moves visibly in the tub.
  • Jets produce strong flow.
  • No humming without rotation, no burning smell.
  • The heater receives flow (if the tub heats, circulation through the heater is working).

Escalation ladder

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

  1. Confirm symptom Verify the pump runs or does not; note if water moves.
  2. Power and GFCI Check breaker and GFCI; do not reset repeatedly if it trips.
  3. Purge air lock Loosen pump union or use air bleeder to purge trapped air.
  4. Filter and suction Clean or replace filter; check suction and intake for blockage.
  5. Call a pro Pump hums but does not turn, burning smell, 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.

  • Whether the pump runs, hums, or does nothing
  • Whether water moves when the pump runs
  • Filter condition
  • Steps already tried

Does the pump run but water does not move?

Turn on the jets. Listen for the pump and check if water moves visibly.

Turn on the hot tub jets. Good: pump runs and water moves—circulation works. Bad: pump runs but water does not move, or pump does not run or hums without turning. If pump hums but does not turn, shut off power immediately.

Yes No

You can change your answer later.

Does the pump run and water move?

If circulation works, the issue may be resolved or intermittent.

If the pump runs and water moves, circulation is working. If the pump does not run at all, check power and GFCI first.
Question

Does the pump run and water move?

Done

Is power on and GFCI reset?

Hot tubs use GFCI. A tripped breaker or GFCI prevents the pump from running.

Check the breaker and GFCI. Reset if tripped. If the breaker trips immediately when you turn on the pump, do not reset repeatedly—call a pro.

Yes No

You can change your answer later.

Did purging air lock fix it?

Air trapped in the pump prevents circulation. Loosen the pump union briefly while running the pump.

With the pump off, loosen the union at the pump inlet (one turn). Turn on the pump briefly; water and air will purge. Tighten when water flows. If circulation returns, the air lock was the cause.
Question

Did purging air lock fix it?

Done

Is the filter clean and suction clear?

A clogged filter or blocked suction restricts flow.

Remove and clean the filter. Check suction and intake for blockage. Reinstall and test.

Yes No

You can change your answer later.

Does the pump hum but not turn?

A humming pump that does not turn usually means a seized impeller or failed capacitor.

If the pump hums but the impeller does not turn, shut off power. Do not let it run. Call a technician.
Question

Does the pump hum but not turn?

Continue

You can change your answer later.

Call a technician

Call a pro if the pump hums but does not turn, you smell burning, the breaker trips immediately, or you are not comfortable with electrical or plumbing work. Pump replacement requires draining and plumbing.

Done

Reviewed by Blackbox Atlas

Frequently asked questions

Why would a hot tub pump run but not circulate water?
Common causes: air lock (air trapped in the pump), clogged filter, blocked suction (skimmer or intake covered), or a failed impeller. Purge air first, then check the filter and suction. A humming pump that does not turn usually means a seized impeller or failed capacitor—call a pro.
Can I fix hot tub circulation myself?
Yes. Power checks, air lock purging, and filter cleaning are DIY. Replacing a circulation pump or impeller requires draining and plumbing work—call a pro if you are not comfortable. Never work on electrical components with wet hands or while standing in water.
When should I call a technician for a hot tub that will not circulate?
Call a pro if the pump hums but does not turn (seized impeller or motor), you smell burning, the breaker trips immediately, or you are not comfortable with electrical or plumbing work. Pump replacement requires draining and plumbing.

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