Hot tub showing a FLO error?
A FLO / FL / FL1 code means the flow switch can't sense enough water past the heater. In about 80% of cases it's a dirty filter or low water — start there. If that's clean, suspect closed valves, an air lock, scale, a failing circ pump or a bad flow switch.
from $149 · $69 diagnostic credited to your repair
A safety switch that's protecting your heater
FLO, FL and FL1 are all flow faults. Before the board lets the heater fire, a flow or pressure switch has to confirm that water is actually moving past the element. If that switch doesn't see enough flow, the board throws the code and locks out the heater so it can't run dry and scorch — exactly the protection you want.
The good news is that most of the time the equipment is fine and the flow is the problem. In roughly 80% of FLO calls the culprit is a clogged filter choking the water path, or simply a low water level pulling air at the skimmer. Closed or half-closed valves after service, and an air lock after a refill, do the same thing. These are the first things to check, and often the cheapest to fix.
When the filter is clean, the water's up and the valves are open, the cause moves to the equipment: scale or biofilm narrowing the plumbing, a circulation pump that's weakening and no longer pushing rated flow, or a flow switch itself that has failed and won't close. That's where a diagnostic earns its keep — measuring actual flow and testing the switch instead of guessing.
We'll confirm which for $69 — credited to the repair
Try the free checks first; if the code stays, these clues point to the cause.
Likely a flow/filter issue if…
- The filter is overdue for a clean or replacement
- The water level sits low at the skimmer line
- It started right after a drain, refill or service
- A valve may have been left partly closed
Likely the pump or switch if…
- The filter is clean and water is full, yet FLO persists
- The circ pump is quiet, intermittent or warm
- Flow feels weak even with everything open
- The code returns minutes after every reset
Restore flow first, then test the switch and pump
Confirm flow
We rule out filter, water level, valves and air lock, then measure the actual flow the heater is seeing.
Flat quote
If it's equipment, you get the published price up front — the $69 diagnostic credited 100% to the work.
Repair
We replace a failed flow switch, rebuild or replace a weak circ pump, or clear scale from the plumbing as needed.
Verify
We confirm the heater fires and holds without the FLO code returning before we leave.
Most flow-error repairs are completed same-day across Palm Beach County.
Try this before you call
Pull and rinse the filter, top the water above the skimmer, and make sure both pump valves are fully open. A surprising share of FLO codes clear right there. If it comes back with a clean filter and full water, the switch or pump is the next suspect — that's our part.
Flat-rate, published up front
Price depends on whether it's the flow switch, the circ pump or a wet-end repair — confirmed at your $69 diagnostic.
Not quite your symptom?
HL / low-flow error
Persistent low flow — a circ or jet pump not pushing water.
PumpLow flow, weak jets
A failing pump, an air lock, or a clogged filter or impeller.
PumpAir lock after a refill
Trapped air stopping the pump from priming.
HeaterWon't heat at all
A locked-out heater from a flow fault or a failed element.
Answers before you call
FLO, FL and FL1 all mean the flow switch can't confirm enough water moving past the heater, so the board locks out heating to protect the element. It's a flow problem, not necessarily a broken part.
Start with the basics: rinse or replace the filter, top the water above the skimmer line, and confirm both pump valves are fully open. Roughly 80% of FLO codes clear with a clean filter and proper water level.
If it returns with a clean filter and full water, the flow itself is short — usually a weakening circulation pump, scale narrowing the plumbing, or a failed flow switch that won't close. Those are diagnosed and repaired on site.
From $149 for a flow/pressure switch, up to a circulation pump replacement or a wet-end repair if the pump is the cause. You get the flat price before we start.
Same-day across most of Palm Beach County, with a real arrival window rather than a vague all-day wait.
Clean filter and still flowing FLO? We'll fix it today.
Flat-rate from $149. Same-day. $69 diagnostic credited to your repair.
Tell us what you've tried — we'll call back within the hour
No call center. Just a local, licensed tech who'll measure your flow and quote the price before any work.
Quote request sent
We'll call you back within the hour. Hot tub out cold right now? Call us at (561) 555-0143.