Is FL1 the same as FLO?

They are closely related. Both indicate insufficient flow, but FL1 is typically a 'low flow' warning while FLO usually indicates the flow switch itself has failed or is stuck open.

Can a dirty filter cause FL1?

Yes — a clogged filter is the #1 cause of FL1. Always clean or replace the filter first before testing other components.

Do I need a plumber to fix FL1?

Usually no. Cleaning the filter or replacing a flow switch / circulation pump are DIY tasks for most spa owners.

🚀 New launch promo — 10% off orders over $300. Use code LAUNCH10

Not sure which part you need? Upload a photo and we'll find it. →

Back to diagnostic

Error Code

FL1 Spa Error — What It Means and How to Fix It

FL1 means your spa is detecting low water flow. The most common cause is a dirty filter cartridge or a blocked circulation pump impeller.

How to diagnose FL1

Check and clean (or replace) your filter cartridge — this fixes FL1 most of the time.
Inspect the circulation pump intake for blockages or debris.
Test the flow switch with a multimeter for continuity when the pump runs.
If steps 1–3 pass, replace the circulation pump or flow switch.

Parts that fix FL1

Iron Might Circulation Pump 3J10020-1E 0.67HP 230V - Bubbles Supply

Frequently asked questions

Still stuck? Our parts team can help.

🔒 Secure checkout · SSL encrypted·🇺🇸🇨🇦 Serving the US and Canada·↩️ 30-day hassle-free returns·📦 Same-day fulfillment

FL1 Spa Error — What It Means and How to Fix It

How to diagnose FL1

Parts that fix FL1

Iron Might Circulation Pump 3J10020-1E

5.5KW 230V Low Flow Heater C3550-1

Pump Seal Assembly SEAL48WTC0153CI

Frequently asked questions