Hot tub OH, OHH and overheat codes
Short answer
OH means the spa water is too hot: 108°F on Gecko packs, 110°F on Balboa (shown as OHS or M029), and 112°F on the 2017 Jacuzzi J-300 and 2016 Sundance 680. Stay out of the water, take the cover off and let it cool.
What you can check yourself
- 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.
Where the owner's part ends
Anything else: turn off power at the breaker and call a technician.
A stuck pump, a failed sensor or a heater that will not switch off is a service call. Turn off power at the breaker. Never bypass the high limit or a temperature sensor.
Every overheat code, system by system
30 codes
| Code | What it means | What to do |
|---|---|---|
| M029Also: OHSBalboa, M codes | Panel: The water is too hotA sensor read 110°F (43.3°C) in the spa water and spa functions stop. It resets on its own below 108°F (42.2°C). Long pump runs or hot weather can cause it. | Stay out
Call if it does not reset once the water cools, or keeps happening. |
| M030Also: OHHBalboa, M codes | Panel: The heater is too hotA sensor read 118°F (47.8°C) inside the heater and the spa shut down. It can be cleared only once the water is below 108°F (42.2°C). | Stay out
Call if it happens again after one reset. |
| M034Balboa, M codes | Panel: A pump may be stuck onA pump appears to be stuck running, and the water may be overheating. | Stay out
Power down the spa and call for service. |
| M035Balboa, M codes | Panel: Hot faultA pump appears to have been stuck on when the spa was last powered. | Stay out
Power down the spa and call for service. |
| OHHAlso: HTR TOO HOTBalboa panel letters | Panel: Heater is too hot118°F (47.8°C) inside the heater; the spa shuts down until the water is below 108°F and the message is cleared. Same fault as M030. | Stay out
Call if it happens again after one reset. |
| OHSAlso: WATR TOO HOTBalboa panel letters | Panel: Water is too hot110°F (43.3°C) in the spa water; functions stop until it falls below 108°F. Same fault as M029. | Stay out
Call if it keeps happening. |
| OHGecko Y series, in.xe | Spa water reached 108°F (42°C). Gecko lists hot weather and long filter cycles as causes. | Stay out
Call if it returns once the water has cooled. |
| AOHGecko Y series, in.xe | The air inside the spa skirt is too hot, pushing the control's internal temperature past its limit. | Technician Call if it does not clear once the equipment area cools. |
| OHGecko in.k1000 | Panel: Spa temperature is too highThe spa water is too hot. | Stay out
Call if it returns once the water cools. |
| AOHGecko in.k1000 | Panel: Elevated internal temperatureThe control's internal temperature is high. | Technician Call if it persists. |
| Flashing temperatureGecko MSPA, SSPA | Panel: Water temperature flashingOn SSPA packs, the water reached 112°F (44°C). It resets by itself at 109°F (43°C). | Stay out
Call if it keeps happening. |
| AOHHot Spring FreeFlow | The equipment compartment reached 194°F (90°C), heating the control past its limits. | Technician Hot Spring says to let the compartment cool until it clears; call if it returns. |
| OHHot Spring FreeFlow | Spa water reached 108°F (42°C). The jet pump stops when the water is about 2°F over the set point to limit friction heat. | Stay out
Call if it persists. |
| OHJacuzzi 2017 | Panel: *OH*Water reached 112°F (44°C). The circulation pump runs and the spa's red lights flash. | Stay out
Contact your dealer if it persists. |
| -- -- -- --Jacuzzi 2017 | Panel: WATCHDOG CALL FOR SERVICEThe watchdog software shut the spa down after detecting a problem that could damage it. | Stay out
Contact your Jacuzzi dealer. |
| Code 29Jacuzzi 2025 on | Panel: Spa OverheatThe water is too hot; spa operation pauses until it cools. | Stay out
Contact your dealer if it keeps happening. |
| Code 30Jacuzzi 2025 on | Panel: Heater OverheatThe heater is too hot; spa operation pauses. | Stay out
Contact your dealer if it keeps happening. |
| Code 34Jacuzzi 2025 on | Panel: StuckOne of the pumps is running continuously. | Technician Contact your dealer. |
| Code 35Jacuzzi 2025 on | Panel: HotWater too hot because a pump is running continuously. | Stay out
Contact your dealer. |
| OHSundance 2016 | Water reached 112°F (44°C); the low-speed pump runs to move water through the heater. | Stay out
Contact your dealer if it persists. |
| - - -Sundance 2016 | Panel: WatchdogThe watchdog software shut the spa down after detecting a problem. | Stay out
Contact your Sundance dealer. |
| Code 29Sundance 880, 2025 | Panel: Spa OverheatSpa water is above acceptable limits. Do not enter the water. | Stay out
Call if it keeps happening. |
| Code 30Sundance 880, 2025 | Panel: Heater OverheatThe heater is too hot. Do not enter the water. | Stay out
Call if it keeps happening. |
| Code 34Sundance 880, 2025 | Panel: StuckA pump may be stuck. | Technician Contact your dealer. |
| Code 35Sundance 880, 2025 | Panel: HotHot fault. | Stay out
Contact your dealer or service company. |
| OHHAlso: HH, HTR TOO HOTVita Spa 2026 | Panel: The heater is too hot118°F (48°C) or more inside the heater; the heater stops until it falls below 108°F. Vita lists long low-speed pump runs, overlapping cycles or a faulty pump as causes. | Stay out
Contact your dealer if it persists. |
| OHSAlso: OH, WATR TOO HOTVita Spa 2026 | Panel: The water is too hotWater entering the heater is 110°F (43°C) or more; the heater stops until it falls below 108°F. | Stay out
Contact your dealer if it persists. |
| Service Code 8Master Spas Legend | Panel: VMS pump: over temperatureThe variable-speed pump overheated. | Check first Nothing to do: this is the spa working as designed. Let it cool; call if it repeats in normal use. |
| Red fire triangleMaster Spas Twilight | Panel: Over-temp errorWater at 108°F (42°C) or higher on the flx.go dial. Master Spas points to heat creep from long filter cycles. | Stay out
Call if it continues after shorter filter cycles. |
| OHNordic, Gecko era | Water reached 112°F (44°C); only freeze protection stays on. Clear it once the water is 109°F (43°C). | Stay out
Call if it persists. |
What is the difference between OH, OHS and OHH?
Where the heat is measured. OH and OHS read the spa water; OHH reads the water inside the heater, which runs hotter. Balboa trips OHS at 110°F in the water and OHH at 118°F in the heater. Gecko's matching pair is OH at 108°F and HL at 119°F. Balboa sends OHH to its flow checklist and Gecko checks for blocked flow on HL, so both lead back to the filter and the valves.
Why does a hot tub overheat?
Mostly from heat it makes without the heater. Pumps warm the water by friction, and a well-insulated tub keeps that heat. Hot Spring's FreeFlow stops the jet pump once the water is about 2°F over the set point for this reason. Jacuzzi calls its version summer logic: from 95°F up, the circulation pump shuts off when the water is 2°F over the setting. Master Spas calls it heat creep and blames long filter cycles.
The other cause is a pump stuck on. Balboa's M034 and M035 say to power the spa down and stay out, because a pump that never stops keeps adding heat. Jacuzzi's watchdog message also shuts the spa off and says to stay out.
What should I do when my hot tub shows OH?
Keep everyone out first. Then let it cool, and only then look for the cause.
If it happens on hot days, shorter filter cycles are the fix the manuals give. See hot tub temperature settings and the HL code.
Common questions
What temperature is too hot for a hot tub?
Jacuzzi's J5 manual warns that water above 104°F (40°C) may be harmful to your health. The overheat codes trip higher than that, at 108°F to 112°F depending on the system, so an OH code means the water is already past that limit.
Will an OH error reset itself?
Often, once the water cools. Balboa's M029 clears by itself below 108°F; Gecko's older SSPA packs reset at 109°F. Balboa's heater message M030 (OHH) waits for you to clear it once the water is under 108°F.
Why does my hot tub overheat in summer?
Pumps add heat as they run, and an insulated tub holds it. Long filter cycles on hot days can push the water past the set point without the heater ever turning on. Gecko and Master Spas both point to shortening filter cycles.
What does OHH mean on a hot tub?
On Balboa systems, the heater is too hot: a sensor read 118°F (47.8°C) inside the heater and the spa shut down. Balboa sends it to the same flow checks as its low-flow messages. Clear it once the water is below 108°F; call a technician if it returns.
Sources
13
- Balboa TP400/TP600 user guide (40940_N), panel messages
- Gecko troubleshooting guide, Y series and in.xe (9919-101313-D)
- Gecko in.k1000 techbook, error messages
- Gecko SSPA-1-AX quick reference card
- Hot Spring FreeFlow Collection owner's manual, 2026
- Jacuzzi J-300 owner's manual, 2017
- Jacuzzi J5 owner's manual (rev A)
- Sundance Spas 680 Series owner's manual, 2016
- Sundance Spas 880 Series owner's manual, 2025 (rev E)
- Vita Spa owner's manual, 2026
- Master Spas Legend Series owner's manual, 2026
- Master Spas Twilight Series owner's manual, 2026
- Nordic Hot Tubs manual with Gecko equipment, 1999 to 2008
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