Inflatable hot tub not heating: Intex, Lay-Z-Spa, SaluSpa

Safety first. Unplug the pump before cleaning ports or removing it, and never open the pump casing. If the GFCI plug trips by itself or fails its test, leave the tub off.

Common symptoms

You turned the heater on hours ago and the water still feels cool.
The display reads the same temperature it did this morning.
The water warms up, then cools off again overnight or after a soak.
The heater light is green, but the water is not as hot as you set it.
An error code appears, such as E90 on an Intex or E02 on a Bestway tub.
The heater worked for days, then stopped on its own.

Quick checks before anything else

The heater is on (the heat light is red) and the set temperature is above the water temperature.
The cover is on and buckled. The bubbles are off while it heats.
The filter cartridge is clean, or you have swapped in a new one.
The water is between the MIN and MAX lines, and the stopper caps are out.
The GFCI plug passes its test (TEST, then RESET).
No heater timer is set to stop or delay heating.
The pump is not in direct sun on a very hot day.

Why is my inflatable hot tub not heating?

It is heating, just slowly Small heaters add only a few degrees an hour, and cold air, wind, an open cover or the bubbles slow them more.
A setting is wrong The set temperature is low, the heater is in standby, or a timer has switched it off. The water cools and nothing seems broken.
Low water flow A dirty cartridge or blocked port stops the heater as a safety step, often with a flow code.
A temperature lockout Water that is too cold or too hot, or a pump that got too hot, locks the heater out until it is back in range.
A failed heater or sensor The water does not change at all after hours of heating with the cover on and good flow.

Slow heater or broken heater?

Set the temperatureAbove the water temperature, heat light red
Cover on, bubbles offClean cartridge in place
Note the readingRun the filter a minute first
Has it risen after 4 to 5 hours?

Yes: the heater works. Give it time, and use the heat-up tips below.

No: check for a code, clear the flow, then reset. If still no change, contact the maker.

Step-by-step: getting an inflatable hot tub to heat

We start with settings and patience, because a heater that looks dead is often just slow. Unplug the pump before you clean the ports, remove the pump or touch anything inside the tub.

Check the set temperature. Intex PureSpa models start at a default of 68 F, so a new tub only heats that far until you raise it. Bestway SaluSpa and Lay-Z-Spa pumps start at 95 F. Both top out at 104 F. Press the heat button and set the number you want.
Read the heat light. On both brands, red means the heater is working and green means the water reached the set temperature and the heater is resting. On an Intex, the heater restarts once the water drops 1.8 to 3.6 F below the setting. If the water has cooled while it sat in standby, Intex says to press the heat button twice.
Clear the timers. On an Intex, a heater start timer can delay heating for up to 120 hours, and a heater duration timer shuts the heater off when its time runs out, even if the water is not hot yet. On a SaluSpa, the power-saving timer runs once and does not repeat until you set it again. Intex pumps also go into hibernation after 72 hours of nonstop heating and show END; the manual’s fix is a button press on the panel to restart the filter pump.
Cover it and turn off the bubbles. Intex lists four things that slow heating: air below 50 F, wind above 8 to 12 mph, the bubbles running while it heats, and no cover. Bestway says heating slows below 59 F air and with the cover off. Never run the bubbles with the cover on.
Give it real time. Intex rates its 4-person PureSpa at about 2 to 3 F per hour, and its 6-person models at about 1 to 2 F per hour. Bestway’s chart for the 120-volt Coleman SaluSpa, with the cover on, shows about 20 hours to reach 104 F from 68 F water and air, and about 32 hours from 50 F. Start with lukewarm fill water to save time, but never pour in water above 104 F.
Clean or swap the cartridge. A dirty cartridge cuts flow, and both makers list it as a cause of slow heating. Intex says to replace cartridges every 1 to 2 weeks; Bestway says to check and clean them daily and change them weekly. Intex suggests a short test run without the cartridge: if a flow code clears, the cartridge was the problem.
Fix any flow code. E90 on an Intex and E02 on a Bestway both mean the pump senses no water flow, and the heater will not run until it does. Check the water level, remove the stopper caps, clean the suction grids or debris screens, and see that the cartridges sit on the right connections. Our Bestway Lay-Z-Spa error codes guide walks through a full E02 flush.
Bring the water into range. Bestway pumps are not designed to run with water below 40 F (E03), and Bestway says to fill with water above 42.8 F. Intex shows E94 when the water is too cold and says to add warm water to bring it above 34 F. If the water is too hot (Intex E95, Bestway E04), unplug and let it cool first.
Reset the heater. On a Lay-Z-Spa with a thermal reset button, Bestway says to press it with a thin object if the temperature has not changed 4 to 5 hours after heating starts, and after first use or a long break. Bestway’s AirJet manual adds that the heater will not run in air above 104 F or in direct sun. On an Intex, unplug, plug back in and reset the GFCI. Intex’s E98, from 131 F water or air, also uses a reset button on the side of the control unit.
Check the reading with a thermometer. Bestway says to run the filter for at least a minute before the display shows the current water temperature. Bestway notes the display can differ from a thermometer by about 2 C (about 3.6 F). If the display and the thermometer both refuse to move after all of the above, the heater, its fuse or a sensor may have failed.

Stop. Do not open the pump casing to test the heater; Bestway says that voids its warranty, and the unit holds mains power next to water. If the GFCI plug trips on its own or fails its test, unplug the tub and leave it off.

Intex PureSpa vs Bestway Lay-Z-Spa and SaluSpa

What changes	Intex PureSpa	Bestway (SaluSpa, Lay-Z-Spa)
Default set temperature	68 F	95 F
Heating rate or time	About 2 to 3 F per hour (4-person)	About 20 hours from 68 F to 104 F (120V SaluSpa, cover on)
Things that slow it	Air below 50 F, wind, bubbles, no cover	Air below 59 F, no cover
No-flow code	E90	E02
Too cold	E94	E03, water below 40 F
Heater lockout codes	E95 too hot, E97 dry-fire protection, E99 sensor broken	E04 too hot, E08 thermal cut-out
Reset	Unplug and reset the GFCI	Thermal reset button on models that have one

For the meaning of every SaluSpa code, see Coleman SaluSpa error codes explained. For any other code, use our error code lookup.

When to call a pool or spa pro

The water has not moved at all 4 to 5 hours into heating, with the cover on, good flow and a reset done.
Intex shows E97 or E99, or a Bestway shows E05. These need the maker’s service center.
Bestway’s troubleshooting chart names a failed heating element or fuse cut-out as a cause. Neither is a part you should open the pump to reach.
The GFCI plug trips by itself, or your household breaker trips when the heater starts. Intex says that can mean an overloaded or undersized circuit, which needs an electrician.

The heater sits inside the pump unit, and both makers send heater faults to their service teams, so have the model and serial number ready. For hard-shell tubs, see hot tub not heating instead.

Common questions

Why won’t my inflatable hot tub heat up?

Most often it is heating, just slowly, or something is holding it back: a low set temperature, the cover off, bubbles running, cold air or a dirty cartridge. A flow code or a too-cold or too-hot code also stops the heater. Our inflatable hot tub problems page explains how the flow sensors and heater work together.

How do I reset the heater on my hot tub?

On a Bestway pump with a thermal reset button, press it with a thin object, then turn the heater back on. Bestway’s full version is: power off for 10 seconds, Reset, Test, Reset on the safety plug, hold On/Off for 3 seconds, press the thermal reset, then press the heater button. On an Intex PureSpa, unplug, plug back in and reset the GFCI.

Where is the thermal reset button on a Lay-Z-Spa?

It is on the side of the pump, on models that have one. It is small, so press it with a thin object such as a pin. If your pump has no button, unplug it for 10 to 20 minutes, plug it back in and do the safety plug reset.

Why is my Intex hot tub not heating up?

Check the set temperature first, because Intex tubs start at 68 F. Then look for a heater timer, standby mode, the END hibernation after 72 hours of heating, or an E90 flow code from a dirty cartridge. Air below 50 F, wind and running bubbles all slow an Intex heater a lot.

How do I get my inflatable hot tub to heat up faster?

Fill it with lukewarm water, never above 104 F, then keep the cover on and the bubbles off until it reaches temperature. Shelter it from wind and run it with a clean cartridge. Expect roughly 2 to 3 F per hour on a 4-person Intex, and about 20 hours or more on a 120-volt SaluSpa starting from 68 F.

My hot tub isn’t heating up even though there’s no error code. What could be the problem?

With no code, the pump thinks all is well, so look at settings and conditions: set temperature, standby mode, timers, cover, bubbles and air temperature. A dirty cartridge can slow heating before it triggers a flow code. If the water has not risen after 4 to 5 hours with all of that right, reset the heater and then contact the maker.