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Custom LeisureScapes • London & Stratford Hot Tub Help
Seeing FLO, HL, OH, NO FLO, DR, M016 or an unfamiliar message? Find out what your hot tub may be telling you, check the safest first steps and know when it is time for a technician.
The quick answer
An error code is a message from the spa’s control system. It may warn about restricted water flow, overheating, a temperature sensor, electrical equipment or a maintenance reminder. The meaning depends on the actual controller and production year—not just the hot tub brand stamped on the shell.
01 · Check the display
Take a photo showing the entire warning, the current water temperature and any other symbols. HL, FLO and Pr can have different meanings on different controllers.
02 · Identify your controls
Select your Bullfrog, MAAX or ŌWOW model below and compare the installed keypad or touchscreen to the manufacturer’s manual. A replacement control can change which codes apply.
03 · Stay safe
If the water is too hot, there is an electrical concern, a pump appears stuck on, or the tub is running dry, stay out and seek qualified help. Never bypass switches or repeatedly reset a fault.
Interactive tool • Step by step
Choose your brand and model, then identify the control panel actually installed on your spa. The finder will show matching manufacturer-documented or controller-family messages, possible causes and owner-safe checks. If your panel is unknown, the guide will not guess what an ambiguous code means.
We never automatically assume that a spa model has the same control system in every year or configuration.
Type letters or words exactly as you see them. On some Balboa panels, an M-number is stored in the fault log while the screen shows a sentence.
READY TO START
Choose Bullfrog, MAAX or ŌWOW above. If you don’t know your model or controller, use the symptom finder below for general, non-electrical first checks.
For an exact diagnosis, refer to the owner’s manual and the identification label for the installed controller. This tool provides educational guidance, not a remote inspection.
Brand-specific troubleshooting
A hot tub’s model number is only one part of the identification. In Southwestern Ontario, owners may be dealing with a newly installed spa, an older model, or a spa whose controller has been replaced during a previous repair. The same two letters can mean entirely different things.
HLIn Bullfrog’s current Gecko-based documentation, HL means the high-limit safety circuit has tripped. On some older Balboa-equipped spas, HL / HFL can instead flag a large temperature-sensor difference associated with poor heater flow.
Do not interpret HL without verifying the control system.
PrIn current Bullfrog A/M-Series message tables, Pr points to defective temperature probes or their detection circuit. On certain older Balboa panels, Pr indicates priming mode at startup—usually not a fault.
Identical letters do not guarantee an identical diagnosis.
Reference library • Easy to scan
These tables help you recognize what an error may mean. They’re grouped by controller family, not just brand; some messages apply only to particular years, optional water-care systems or spa packs. The interactive finder above supplies more detailed first checks after you confirm the control.
| Message | Meaning | Suggested response |
|---|---|---|
HL | High-limit circuit has tripped. | Stop use; assess overheating and seek professional guidance. |
FLO, FLO-L01, FLO-L02 | Water flow condition detected. | Check level, filter condition and normal circulation safely. |
NO FLO / CFLO | No flow or a persistent no-flow condition. | Heating may be stopped. Arrange service if normal flow is not restored. |
OH, HR, Hr | Overtemperature, relay hardware, or thermal safety warning. | Do not enter; qualified service is appropriate. |
Pr, AOH | Temperature-probe fault or high internal equipment temperature. | Professional diagnosis may be needed. |
FLC, SP in, UPL | Pressure-switch, supply-voltage or invalid software condition. | Record the exact code; contact trained service personnel. |
Source: Bullfrog’s 2026 A Series and M Series owner manuals. X Series and earlier production years may have different wording or codes. View Bullfrog owner manuals.
| Code / displayed message | Meaning | What to do first |
|---|---|---|
M016 • Water flow is low | Flow through the heater may be insufficient. | Confirm water level and normal circulation. |
M017 • Water flow has failed | Heater is disabled due to inadequate flow. | Do not repeatedly reset; service if unresolved. |
M028 / M027 | Heater may be dry / heater is dry. | Do not run a dry pump; follow refill/priming guidance. |
M029 / M030 | Spa water overheated / heater overheated. | Do not enter water; follow the safety instructions. |
M015 / M026 | Temperature sensors disagree; persistent mismatch. | Arrange service if the condition persists. |
M031 / M032 | Temperature sensor A / B fault. | Contact a qualified technician. |
M034 / M035 | Possible stuck pump / hot fault. | Power down as directed; do not enter. |
M036 | GFCI safety test failed. | Contact qualified service; never bypass protection. |
This code family requires a confirmed Balboa BP-series control pack. A TP500 or TP700 is the panel name; not every panel/pack combination has every message. ŌWOW manuals.
| Code | What it indicates on compatible older controls | Priority |
|---|---|---|
HH / OHH, OH / OHS | Heater or spa water too hot. | Stop use. |
SA, SB, SN | Temperature sensor faults or disagreement. | Service if persistent. |
HL / HFL, LF | Potential or persistent inadequate heater water flow. | Check water/flow; service if repeated. |
DR, DY | Possible or confirmed dry-heater condition. | Do not force continued operation. |
IC, Pr, -- -- | Freeze protection, priming mode or unknown temperature. | Often informational, subject to context. |
MAAX owner note: These tables are not a claim that all MAAX models use Balboa, Gecko or any one keypad. Check the exact pack and year, particularly on spas sold under MAAX or American Whirlpool names.
Before you book a repair
Flow-related faults often appear after a water change, when a filter becomes restricted, or when water level falls. These checks are deliberately limited to owner-visible items. Do not open a live electrical cabinet, loosen plumbing connections on energized equipment or bypass a protective device.
Compare the water line with the fill indicator in your spa’s manual. A low level can let air enter the circulation system, especially while jets run.
Observe jets, return flow or circulation indicators without opening the equipment. If a pump runs loudly but moves no water, stop following the manual’s instructions.
A dirty or incorrectly seated cartridge may impede circulation. Follow the manufacturer procedure for shutting power off before handling filters, then clean or replace as directed.
An airlock may follow draining and refilling. Use only the owner-level priming procedure specified for your control; do not let a pump run dry.
Some systems use Ready/Rest, Standard/Economy or scheduled heating. A lower setting can mimic a heater fault. Do not override a genuine overheating or no-flow message.
Note the time, message, outside temperature, recent cleaning, power outage, refill or chemical adjustment. A clear service note can help the technician work efficiently.
No code? Still need answers?
Start by comparing current and set temperature, then check the selected heating mode, water level and filter maintenance. A flow problem can prevent heating even while some jets work. A failed heater, sensor or electrical component needs service.
Low water, closed jet controls, clogged filters, trapped air after refilling or a circulation problem may reduce performance. Don’t keep running a noisy pump without normal flow.
Repeated tripping may point to an unsafe electrical condition or faulty equipment. Do not repeatedly reset the breaker or open the spa pack. Contact a licensed electrician or qualified spa technician.
A spa may need to prime its pumps, clear trapped air, recognize a proper water level and re-establish temperature sensing. Follow the exact startup procedure in the manual rather than copying steps from a different brand.
Possible causes include trapped air, flow restriction, a failing pump or a motor issue. If there is grinding, burning smell, unusual heat or no water movement, stop the affected equipment and request service.
This is usually a water-care issue rather than a control-panel error. Start with a reliable water test, assess sanitizer and pH, clean filtration and review bather products. Never mix chemicals or guess at treatment amounts.
Especially important in Southwestern Ontario
Frozen plumbing can turn a manageable heater or flow problem into a much larger repair. Cold weather does not change what an error code means, but it changes how quickly the problem deserves attention.
Confirm the display has resumed normally, the spa is still heating and water is moving. Don’t assume automatic recovery without looking at the actual water temperature.
If water flow stops or the temperature keeps falling, seek qualified advice promptly. Do not disable freeze protection, repeatedly cycle faulty equipment or leave an unattended spa without heat.
Water can remain inside plumbing and pumps even after the shell is empty. Winterization requires the correct model-specific procedure, not just opening the drain.
For a season-long plan, read Is My Hot Tub Ready for Winter?. If you are shutting the spa down, see hot tub winterizing and closing rather than treating a standard drain as winterization.
Frequently asked questions
FLO usually points to a water-flow or circulation condition on compatible controllers, but the exact meaning and response depend on the installed spa pack. Check the correct fill level, visible circulation and filter maintenance according to your manual. If the heater is disabled or the warning persists, arrange service.
It depends on the controller. In Bullfrog’s 2026 A/M-Series documentation, HL means the high-limit safety circuit has tripped. On some older Balboa controls found in other spas, HL/HFL refers to a sensor-temperature difference that may suggest inadequate flow. Never use an HL definition without confirming your panel.
On applicable Bullfrog controls, Pr is listed as a temperature-probe or detection-circuit warning. On some older Balboa panels, Pr means priming mode after startup. The safest next step is to identify the controller and year before doing anything more.
Check the actual temperature, heat mode, scheduled filtration and water level first. A dirty filter or insufficient heater flow can sometimes disable heating. Sensor faults, heater problems and electrical components require qualified diagnosis.
No. MAAX and American Whirlpool spas have used different controls across models and production years. Confirm the installed keypad and equipment pack or the exact owner manual before using a Gecko- or Balboa-specific message table.
On applicable Balboa BP-series controls, M016 indicates low heater flow, M017 indicates failed heater flow and M029 indicates excessive spa-water temperature. The actual screen may show words instead of the M-number, which can appear in a fault log. These definitions should not be applied to a portable VL260 panel.
Only when your model’s manual instructs you to, after the underlying cause has been corrected. Do not repeatedly clear overheating, dry-heater, pump, electrical or high-limit faults. Never bypass flow switches, GFCI protection or thermal safety devices.
Treat the loss of heat or circulation as time-sensitive. Record the exact message, check only owner-visible items, and contact a qualified spa service provider promptly. Do not simply drain the shell; freezing water may remain in the plumbing and equipment.
Custom LeisureScapes offers hot tub diagnostics and service for London, Stratford and surrounding Southwestern Ontario communities. You can describe the brand, model, symptoms and error message through its hot tub service request page.
Local service, real answers
Based in London and Stratford, Custom LeisureScapes helps spa owners across Southwestern Ontario with hot tub troubleshooting, diagnostics, maintenance and seasonal care. Save the error code and a clear photo of your display before you request service.
London: 775 Wharncliffe Rd S • Stratford: 404 Erie St • Serving Middlesex, Perth, Elgin and Oxford Counties and surrounding communities.
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