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What HL means on a hot tub, by control system

Short answer

HL means two different things. On Gecko packs it is a high-limit trip: the water inside the heater reached 119°F (122°F on Hot Spring's FreeFlow). On some Balboa panels HL is short for heater flow loss, a low-flow warning. Check which system your tub has before you act on it.

Updated By the HotTubFinder research desk

What to check first for a hot tub error code: for an overheat code, stay out and take the cover off; otherwise clean the filter, top up the water, open the valves and purge any air lock, reset the breaker once, then call a technician
What to check first for any code, in order, before you call a technician.

What you can check yourself

  1. Stay out of the water.
  2. Take the cover off so the water can cool.
  3. Clean the filter, or replace it if it is worn.
  4. Open any closed valves and jets.
  5. Turn the power off at the breaker for 30 seconds, then back on. Once.

Where the owner's part ends

Anything else: turn off power at the breaker and call a technician.

A high limit that trips again after one reset is a service call. Turn off power at the breaker. Never bypass or jumper a high-limit switch or sensor.

On Gecko packs

High limit tripped

Water inside the heater reached 119°F (48°C). Stay out of the water.

On some Balboa panels

Heater flow loss

Too little water through the heater; it retries after about a minute.

How do I tell which HL I have?

Find out who made your control. The brand table on the error codes page shows what each maker's manual prints, by model line. Bullfrog's 2026 A Series, Master Spas' Legend and Cal Spas' Gecko models print Gecko's list, where HL is the high limit. Tubs with Balboa equipment show HFL or HL for low heater flow; on Balboa's VL panels, five of them in 24 hours turn into LF.

If you cannot tell, treat it as the high limit: stay out, let the water cool, and check the filter.

Every HL and high-limit code, system by system

13 codes
Every HL and high-limit code we recorded, by the system or manual that defines it
CodeWhat it meansWhat to do
M016Also: HFLBalboa, M codesPanel: The water flow is lowNot enough water is moving through the heater to carry the heat away. The heater waits about a minute and tries again.Check first
  • Check the water level and top it up to the line in your manual.
  • Clean the filter, or replace it if it is worn.
  • Open any closed valves and jets.
  • Purge an air lock the way your owner's manual describes.

Call if it keeps coming back after the checks.

HFLAlso: HL, HTR FLOW LOSSBalboa panel lettersPanel: Heater flow is reducedLow flow through the heater during heating; the heater retries after about a minute. Same fault as M016. Balboa's service manual lists HL as another panel's name for it.Check first
  • Check the water level and top it up to the line in your manual.
  • Clean the filter, or replace it if it is worn.
  • Open any closed valves and jets.
  • Purge an air lock the way your owner's manual describes.

Call if it keeps returning.

HLGecko Y series, in.xeWater inside the heater reached 119°F (48°C) and the high limit tripped. The heater body may be very hot.Stay out
  • Stay out of the water.
  • Take the cover off so the water can cool.
  • Clean the filter, or replace it if it is worn.
  • Open any closed valves and jets.

Call if it trips again after one power reset.

HLGecko in.k1000Panel: High Limit circuit has trippedThe heater's high-limit safety circuit has tripped.Stay out
  • Stay out of the water.
  • Take the cover off so the water can cool.
  • Clean the filter, or replace it if it is worn.

Call if it trips again.

HLGecko MSPA, SSPAA high-limit fault. It blinks when the water itself reads 112°F (44°C) or more; a steady display points to the high-limit sensor or heater.Stay out
  • Stay out of the water.
  • Take the cover off so the water can cool.
  • Clean the filter, or replace it if it is worn.
  • Open any closed valves and jets.

Call if it does not clear.

Red flashing, all three lightsHot Spring 2026Panel: Protection ModeA high-limit, heater relay or internal fault. Heater and jets are off; circulation stays on.Stay out
  • Stay out of the water.

Call for service.

Blue logo light flashingHot Spring 2026Panel: Power light flashingThe heater high limit has tripped: the water is too hot, or something such as a clogged filter cut circulation.Check first
  • Turn the power off at the breaker for 30 seconds, then back on. Once.
  • Clean the filter, or replace it if it is worn.

Call if it trips again.

-----Hot Spring Hot SpotPanel: ----- with POWER flashingThe heater high limit tripped and the whole spa is off.Check first
  • Turn the power off at the breaker for 30 seconds, then back on. Once.
  • Clean the filter, or replace it if it is worn.

Call if it keeps tripping.

HLHot Spring FreeFlowThe heater shut off when the temperature at the heater reached 122°F (50°C).Stay out
  • Stay out of the water.
  • Take the cover off so the water can cool.
  • Turn the power off at the breaker for 30 seconds, then back on. Once.

Contact your dealer if it does not reset.

Gray logo light blinkingCaldera 2026Panel: Power indicator blinkingThe heater high limit has tripped: water above range, or low circulation such as clogged filters.Check first
  • Turn the power off at the breaker for 30 seconds, then back on. Once.
  • Clean the filter, or replace it if it is worn.

Call if it keeps tripping.

Power blinking, four lines on displayCaldera 2026Panel: Four lines (Paradise)On the Paradise Series, the heater high-limit thermostat tripped.Check first
  • Turn the power off at the breaker for 30 seconds, then back on. Once.
  • Clean the filter, or replace it if it is worn.

Call if it keeps tripping.

HFLAlso: HL, HTR FLOW LOSSVita Spa 2026Panel: The water flow is lowA heater flow problem: the heater stops while the spa keeps running. A plugged filter or low water can cause it.Check first
  • Clean the filter, or replace it if it is worn.
  • Check the water level and top it up to the line in your manual.
  • Open any closed valves and jets.

Contact your dealer if it persists.

HLNordic, Gecko eraWater at the heater reached 119°F (48°C) and the heater shut down. Clear it once the water is 109°F.Stay out
  • Stay out of the water.
  • Take the cover off so the water can cool.
  • Clear the message on the panel once the cause is fixed.

Call if it persists.

What is a hot tub high limit?

A second temperature cutoff on the heater, separate from the thermostat that holds your set temperature. Its job is to switch the heater off when the water inside it gets too hot, even if the thermostat is still calling for heat. Gecko's older MSPA packs used a sensor touching the heater barrel for it. Hot Spring tubs show a trip as a flashing blue logo light and reset it when the power is off for 30 seconds.

It trips for the same reasons flow codes appear. Hot Spring's list is a clogged filter, a plumbing blockage, a circulation pump that is not running, draining without turning the power off first, and an air lock.

Common questions

What does HL mean on a hot tub?

On Gecko-equipped tubs, the heater's high limit tripped because water inside the heater got too hot. On some Balboa panels, HL is the heater flow loss message, which means too little water is moving through the heater.

How do I reset an HL error?

Let the water cool with the cover off, then cycle the power once. Hot Spring's FreeFlow manual says to shut the power off and back on to reset it. If HL comes back, turn off power at the breaker and call a technician.

What trips a hot tub high limit?

Hot Spring's manual lists a clogged filter, a blockage in the plumbing, a circulation pump that is not running, draining the tub with the power on, and an air lock. All of them stop water moving through the heater.

Can I bypass the high limit to get my hot tub working?

No. The high limit is what cuts the heater off when the water inside it gets too hot, whatever the thermostat says. The manuals we read treat a repeat trip as a service call.

Sources

15
  1. Balboa TP400/TP600 user guide (40940_N), panel messages balboawater.com · checked October 2026
  2. Balboa troubleshooting and service manual for EL/VS systems balboawater.com · checked October 2026
  3. Getaway Hot Tubs owner's manual, 2026 (Master Spas) masterspascdn.com · checked October 2026
  4. Gecko troubleshooting guide, Y series and in.xe (9919-101313-D) geckoalliance.com · checked October 2026
  5. Gecko in.k1000 techbook, error messages geckoalliance.com · checked October 2026
  6. Gecko MSPA-1-AX spa pack service manual geckoalliance.com · checked October 2026
  7. Hot Spring Highlife Collection owner's manual, 2026 d1oxc6ayqrhsgs.cloudfront.net · checked October 2026
  8. Hot Spring Hot Spot Collection owner's manual, 2026 d1oxc6ayqrhsgs.cloudfront.net · checked October 2026
  9. Hot Spring FreeFlow Collection owner's manual, 2026 d1oxc6ayqrhsgs.cloudfront.net · checked October 2026
  10. Caldera Spas Utopia Series owner's manual, 2026 d1oxc6ayqrhsgs.cloudfront.net · checked October 2026
  11. Caldera Spas Paradise Series owner's manual, 2026 d1oxc6ayqrhsgs.cloudfront.net · checked October 2026
  12. Vita Spa owner's manual, 2026 res.cloudinary.com · checked October 2026
  13. Nordic Hot Tubs manual with Gecko equipment, 1999 to 2008 nordichottubs.com · checked October 2026
  14. Balboa VL401 user guide (40789_G), diagnostic messages balboawater.com · checked October 2026
  15. Bullfrog Spas A Series owner's manual, 2026 (v1.9) bullfrogspas.com · checked October 2026

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