A code on the panel is the tub telling you why it stopped. It's worth reading properly before you reset anything, because the fix for one code is the wrong move for another.
The catch is that there's no single list. The control maker decides what the letters mean, and two of them use the same letters for different faults.
Everything below comes from Balboa's and Gecko's own user guides and service manuals, and from the owner's manuals of the spa makers that print their codes. Where they disagree, I say so.
Key takeaways
- The same letters mean different things on different controls. HL is low flow on an older Balboa panel and an overheated heater on a Gecko pack.
- Flow codes, such as HFL, LF, dr and FLO, are the owner's to fix: water level, filter, valves and trapped air.
- Overheat codes, such as OH, OHS, OHH and a Gecko HL, mean don't get in. Take the cover off and let the water cool.
- Balboa shuts the tub down at 110°F in the spa or 118°F in the heater. Gecko's limits are 108°F and 119°F.
- A stuck-pump message means power the tub down and call for service. Balboa says not to enter the water.
- Sensor, memory and hardware codes are for a technician. Balboa and Gecko both say their packs have no user-serviceable parts.
First, find out whose control it is
Look in your owner's manual for the code list. It's in a section called something like diagnostic messages or error codes. The spa makers either reprint their control maker's list or write their own.
- Balboa's messages and M-numbers are printed in the Jacuzzi J-200, Marquis Crown and Cal Spas Escape manuals. Jacuzzi's J-300 and Sundance's 880 list the same faults by number: their "Code 16" is Balboa's M016. Balboa's own service manual says its message codes are the same for all its TP panels.
- Gecko's codes are printed in the Bullfrog, Hydropool and ThermoSpas manuals. Arctic's lists them for its Classic and Core tubs.
- Their own: Hot Spring and Caldera use indicator lights, and Hot Spring's Highlife adds E-numbers. Jacuzzi's J-400 and J-LX show messages in words, and Arctic's Custom series has its own ER codes.
Why it matters. Three examples from the manuals:
- HL. On Balboa's older VL panels it means a big difference between the heater's two sensors, which Balboa says could mean a flow problem. On a Gecko pack it means the water in the heater has reached 119°F.
- Pr. On Balboa's ML panels it's priming mode, which is normal at power-up. On Gecko's in.k500 and in.k1000+ keypads it means the temperature probes are defective.
- Dashes. On a Balboa panel they mean the temperature isn't known yet. On a Hot Spring Hot Spot they mean the heater's high-limit has tripped.
What the codes mean
The codes fall into four groups, and each group has its own first move.
Flow codes: yours to fix
These mean water isn't moving through the heater the way the control expects, so it has turned the heater off to protect it.
| What it means | What happens next | |
|---|---|---|
| HFL or HL (older Balboa) / The water flow is low, M016 | Not enough flow through the heater | Balboa says the heater tries again after about a minute |
| LF / The water flow has failed, M017 | Low flow again and again: the fifth HFL in 24 hours, in Balboa’s older guides | Heater off, the rest runs. Fix the flow, then press a button |
| dr / The heater may be dry, M028 | Too little water in the heater: low water, poor flow or air bubbles | The spa shuts down for 15 minutes, then tries again |
| dY or drY / The heater is dry, M027 | The third dr in a row | Stays off until you fix it and press a button |
| FLO (Gecko) | No flow while the main pump runs | Gecko: check the filter, pump, blockage, air lock and water level |
| NO FLO (Gecko) | The flow problem has persisted | Everything off until it’s fixed |
Balboa's checklist for every flow message names six things: low water level, suction flow restrictions, closed valves, trapped air, too many closed jets and pump prime. Gecko's keypads say to check the filter, pump, blockage, air lock and water level. Gecko's card for the in.xe pack adds open the water valves, clean the filter, and call your dealer if it persists.
The filter first. It's the cheapest thing on either list, and the filter guide has the makers' cleaning steps.
Trapped air after a refill. Balboa's TP700 guide says the pump that feeds the heater has to be free of trapped air, and to remove it "by priming this pump." Balboa's priming mode runs for 4 minutes at power-up, with the heater locked out. Balboa adds two limits: don't run an unprimed pump for more than 2 minutes, and don't switch it off and on more than 5 times to help it prime. The jets guide has the makers' airlock fixes in full.
If it comes back. Balboa's guides say to contact your dealer or service company if a flow problem persists. Its service manual also says LF needs the power cycled before the heater will work again, where its owner guides say a button press. I try the button first.
Too hot: stay out
These mean the water in the spa, or in the heater, is hotter than the control allows. The tub has shut itself down. Balboa's older guides, Gecko, Jacuzzi and Dimension One all say the same thing about it: don't get in.
| What it means | What the maker says to do | |
|---|---|---|
| OHS or OH (older Balboa) / The water is too hot, M029 | Spa water at 110°F | Stay out, cover off. It resets itself below 108°F, or 107°F on older systems |
| OHH or HH (older Balboa) / The heater is too hot, M030 | 118°F in the heater | Stay out, cover off. Press a button once the water is below 108°F |
| OH (Gecko) | Spa water at 108°F | Stay out, cover off, let it cool. Call your dealer if it persists |
| HL (Gecko) | Water in the heater at 119°F | Stay out, cover off, let it cool, then switch the power off and on |
| AOH (Gecko) | The inside of the cabinet is too hot | Open the skirt and wait for it to clear |
Why it happens. Balboa's guides say to check for extended pump operation or high air temperature. Its oldest card says overheating may occur if the filter cycle is set too long. Flow matters here too: Balboa's overheat steps for the heater send you to the same flow checks as above.
Gecko's HL can trip the GFCI. Gecko's troubleshooting guide says its Y-series packs have a circuit that trips the GFCI when an HL occurs. Jacuzzi's J-400 shows "GFCI Trip Error" when the spa has tripped the breaker over "excessive heat." So a tripped breaker after an overheat may be the tub doing its job. The GFCI guide covers the rest.
Sensors and hardware: call for service
These mean the control can't trust its own readings, or something inside it has failed. The manuals give the owner no repair step beyond a reset.
- SnA, Snb, SA, Sb (Balboa): the sensor in jack A or B isn't working. Balboa says it can appear briefly during an overheat and disappear when the heater cools.
- SnS or Sn, and "Sensors are out of sync" (M015, M026): the two sensors disagree. Balboa's guides say it may be temporary if it alternates with the temperature. M026 means it has lasted an hour, and the guides say call for service.
- Prr or Pr (Gecko): a problem with the temperature probe. Gecko's card says call your dealer.
- Hr and HR (Gecko): a hardware error inside the pack.
- Memory, clock and configuration errors (Balboa): the guides say contact your dealer, some only if the message shows on more than one power-up.
- M036, "The GFCI test failed" (Balboa): the control couldn't trip its GFCI, which Balboa says may mean an unsafe installation.
That's the line. Balboa's service manual says its controls have "absolutely no end user serviceable parts," and that non-qualified users should never open or remove covers. Gecko's keypad manuals say only qualified personnel should service the unit.
Stuck pump: power it down
M034, "A pump may be stuck on," and M035, "Hot fault." A pump that's stuck on keeps running, and Balboa's ML260 guide says that can make the water temperature creep up "possibly to hazardous levels." Its older ML panels show StU and HOt for the same two faults. Balboa's TP700 guide gives one instruction for both: "POWER DOWN THE SPA. DO NOT ENTER THE WATER." Then contact your dealer or service company.
- 1
Write down the code and find whose control it is
5 minNote exactly what the panel shows, and whether it alternates with the temperature or flashes on its own. Balboa's guides say a sensor message that alternates may be temporary, and one that flashes alone means the spa has shut down. Then find the code list in your owner's manual.
- 2
Stay out if it's a heat or stuck-pump code
1 minOH, OHS, OHH, HH, and HL on a Gecko pack mean the water or the heater is too hot. Take the cover off and let it cool. A stuck-pump message means switch the power off at the breaker and call for service.
- 3
Check the flow
15 minFor a flow code, check that the water is at the level your manual gives. Take out and clean the filter, open any closed valves and jets, and make sure the suction covers are clear. After a refill, run the priming mode to clear trapped air.
- 4
Reset it the way your manual says
2 minBalboa's guides say any button press resets most of its messages, and some clear themselves. Gecko's card says to switch the power off and back on after an HL. Hot Spring and Caldera reset the heater's high-limit by cutting the power for 30 seconds.
- 5
If it comes back, call for service
5 minA code that returns after you've fixed the flow needs a technician, and so does any sensor, memory or hardware code. Tell them exactly what the panel showed and when. Newer Balboa panels keep a fault log the technician can read.
Messages that aren't faults
Some messages look like errors and aren't.
- Freeze protection. Balboa's "Possible freezing condition," "TOO COLD," ICE and IC mean the control has started the pumps to keep the plumbing from freezing. Balboa's guides call it "an operational message, not an error indication." ThermoSpas says its ICE message starts below 44°F. The winter guide has what the makers say about cold weather.
- Dashes. On Balboa's panels, the temperature isn't known until the pump has run for a minute, or two minutes in some of its guides. In an economy or sleep mode the pump may be off for hours, so the reading isn't current.
- Pr on a Balboa ML panel. Priming mode, for up to 4 minutes after power-up.
- Reminders. Balboa's panels can remind you to check the pH, change the filter, change the water and test the GFCI. Balboa says the spa maker sets how often each appears, and its TP500 guide says a temperature button clears one.
- Water readings. Some Balboa panels show PHL, PHH, SAL and SAH for low or high pH and sanitizer. The water chemistry guide covers what to do about them.
Hot Spring, Caldera and the other makers' panels
Hot Spring and Caldera. The power indicator blinks when the heater's high-limit has tripped: Hot Spring's Highlife blinks its logo light, and Caldera's panel blinks its power light. Hot Spring's Hot Spot shows dashes instead. All three manuals say to cut the power for 30 seconds to reset it, and Caldera's says a tub that comes back on after that points to reduced flow through the heater. Hot Spring's Highlife shows E-numbers with its logo lights: E2 means no flow, check the filter, and E5 and E6, a sensor fault or no power to the heater, mean call for service.
Jacuzzi J-400 and J-LX. Messages in words, such as "Flow Restriction" and "Overheat protection," with a red light. The overheat entries say "Remove spa cover to speed cooling" and contact your dealer. Jacuzzi says an error that isn't fixed reappears in 2 hours.
Dimension One. Its @Home manual gives the overheat point as over 112°F, says to let the water cool below 110°F, then "reset your GFCI to restart your spa." It also says to contact your dealer immediately for service.
Arctic's Custom series. ER01 is the flow switch, ER02 the heater over temperature, ER03 the spa over temperature and ER04 the spa's temperature probe. The manual gives no action for them.
Inflatable tubs
Inflatable tubs have their own codes, and the two brands' lists don't match each other.
Intex PureSpa:
- E90: no water flow. Clean or replace the cartridge, and check the outlet grid and the connections.
- E94 and E95: water too cold or too hot. For E94, the 2025 manual says to add warm water to raise the water above 34°F, and not to use the spa when the air is below 32°F.
- E96: a system error. Unplug it and restart.
- E97 and E99: dry-fire protection or a broken temperature sensor. Both mean contact Intex.
- END: the pump has run 72 hours of continuous heating and has gone to sleep. Press the filter button to start it again.
Bestway, from its US manual:
- E02: not enough water flow. Bestway's first checks are the 2 stopper caps and a dirty cartridge.
- E03: water below 39°F. Unplug the pump and restart it at 50°F.
- E04 and E08: water over 119°F and over 116.6°F. Unplug and let the water cool to 100°F before restarting.
- E18: electricity detected on the ground wire. Call an electrician immediately.
Bestway's fix for E01, where the pump senses flow that isn't there, is to unplug it and "strike the side of the pump but not violently." That's as far as I'd go. Bestway's own warranty excludes pumps that have been "opened and/or tampered with."
Where the makers disagree
- The same letters. HL is low flow on Balboa's older panels and a 119°F heater on Gecko's. Pr is priming mode on Balboa's ML panels and a probe fault on Gecko's in.k500 and in.k1000+.
- When the spa water is too hot. Gecko says 108°F. Balboa says 110°F on its newer systems and 112°F on its oldest. Dimension One says over 112°F.
- When it resets. Balboa's newer guides say below 108°F, its older ones 107°F, and its oldest card 110°F.
- How to reset. Balboa says press a button for most codes. Gecko's card says cycle the power after an HL. Hot Spring and Caldera say cut the power for 30 seconds. Cal Spas says to turn the tub off at the GFCI for 15 to 30 minutes after its heater-too-hot code, and Dimension One says to reset the GFCI.
- A stuck pump. Balboa's guides say power down and call for service. Its Spa Touch mini guide says turn the breaker off and back on to reset.
- The failed GFCI test. Balboa's guides say contact your dealer. Its Spa Touch mini guide says contact a licensed electrician.
- Misprints. Cal Spas' 2025 manual prints the GFCI self-test description under M034, the stuck-pump code. Jacuzzi's J-200 numbers the Sensor B fault M028, which is Balboa's "heater may be dry" code; Balboa's guides say M032.
- Gecko's own documents. Its keypad manuals spell the probe fault Pr in some and Prr in others. They describe Hr as a thermal fuse error, a thermistor error or a general hardware error. The flx.go table defines OH as a hot cabinet, against its own earlier page, which says spa water at 108°F.
- Bestway by market. Its US manual trips E04 at 119°F and E08 at 116.6°F. Its UK Lay-Z-Spa manual trips E04 at 122°F and E08 at 125.6°F.
Frequently asked questions
What does FLO mean on a hot tub?
It's a Gecko code for no water flow. Gecko's card says the system doesn't detect any flow while the main pump is running, and its keypads say to check the filter, pump, blockage, air lock and water level. NO FLO means the problem has persisted and everything has been switched off.
What does OH mean on a hot tub?
Overheat: the spa water is too hot. On a Gecko pack it means the water reached 108°F. On Balboa's older numeric panels it means 110°F, or 112°F on its oldest controls. Don't get in. Take the cover off and let the water cool, and call for service if it doesn't clear.
What does HL mean on a hot tub?
It depends on the control. On a Gecko pack, HL means the water in the heater reached 119°F and the heater has shut down. Don't get in. On Gecko's Y-series packs, the GFCI may have tripped too. On Balboa's older VL panels, HL means low flow through the heater.
What does dr mean on a Balboa hot tub?
The heater may be dry: Balboa's control found too little water in the heater, from low water, poor flow or air bubbles. The spa shuts down for 15 minutes and then tries again. On the third time it shows dY or drY and stays off until you press a button.
What do SnA, Snb and SnS mean on a hot tub?
They're Balboa sensor messages. SnA and Snb mean the sensor in jack A or B isn't working, and SnS means the two sensors disagree. Balboa says any of them can appear briefly during an overheat. If one stays, call your dealer or service company.
Why does my hot tub show dashes instead of the temperature?
On a Balboa control, dashes mean the temperature is unknown until the pump has run for a minute or two, or that the tub is in an economy or sleep mode with the pump off. On a Hot Spring Hot Spot, dashes mean the heater's high-limit has tripped.
Can I clear a hot tub error code by turning the power off and on?
Sometimes. Gecko's card says to do it after an HL, and Hot Spring and Caldera reset their high-limit by cutting the power for 30 seconds. Balboa clears most of its codes with any button press instead. A stuck-pump message is different: Balboa says power down, stay out and call for service.
What do E90 and E02 mean on an inflatable hot tub?
Both are flow codes. On an Intex PureSpa, E90 means no water flow, and Intex says to clean or replace the cartridge and check the outlet grid and the connections. On a Bestway inflatable, E02 means the pump isn't detecting enough water, and the first things Bestway lists are the stopper caps and a dirty cartridge.
