Why is my spa pool not heating? Step-by-step troubleshooting guide

You’re ready to have a relaxing warm soak, but you realised your spa isn’t heating or isn’t as warm as you would like. Why is your spa not heating? There are several possible reasons why. In this article, we’ll cover the top 5 reasons why the spa is failing to heat water, along with troubleshooting guides to fix them.

why is my spa not heating

There's nothing quite like a relaxing soak in a spa pool, but if the water is not heating up properly, it can be frustrating and unsatisfying.

There can be several reasons why your spa pool may not be heating up, and in this article, we'll explore some of the most common causes and what you can do to fix them.

Important note: All electrical work must be carried out by a licensed electrician. Any electrical information included here, whether it is troubleshooting or other instructions, are provided for use by a licensed electrician only. Local electrical codes supersede any information found here.

Spa Not Heating Troubleshooting Guide

Why is my spa pool not heating?

Here are the top 5 possible reasons your spa is not heating, including steps on how to fix them.

Power to spa has failed (or breaker tripped)

The main function of the breaker is to monitor the currents flowing into the spa. The power to the spa is switched off if it detects a loss of electrical current. Spa breakers can be highly durable depending on their quality, but they eventually wear out.

Why is there no power to my spa?

If there’s no power to your spa, heating the water isn’t the only problem. Clearly, you won’t be able to get anything working. The most likely cause of no power to your spa is a tripped breaker.

What made it trip? Moisture in the outlet, voltage irregularities such as short circuits, ground faults, and circuit overloads may cause the breaker to trip.

How do I test for a faulty spa circuit breaker?

Step 1: Locate the circuit breaker panel (it is usually found inside a smaller panel hooked up to the spa or near the spa). Or it may be on your main fusebox for the property.

Step 2: Check the circuit breaker, if it is in the OFF position, switch it back to the ON position.

Step 3: If the breaker trips again, turn everything off in your spa and disconnect the main power inlet.

*Note: If your spa or electrical equipment on the circuit is hardwired, you need to consult a registered electrician to disconnect anything.

Step 4: Turn the circuit breaker on again

Step 5: Observe the breaker. If the breaker doesn't trip off this time, some components in your spa could be the problem. If the breaker trips with nothing connected the circuit breaker might be faulty and will need replacing.

The heater element is not working/failed.

Spa heaters come in various shapes and are typically composed of an element in a stainless steel case. Heat is transferred from the element to the water as it passes through. Sensors, like a high-limit switch and thermostat, may also be included in the heater assembly.

If your spa is not heating, often the problem is the heater element itself. There are several tests to be done if this is the case.

How do I know if my heating element is bad in my spa or hot tub?

Testing the voltage to the heater with a multimeter will help determine if your heating element is bad. Before performing the test, it’s crucial to ensure all power to the spa is shut off.

  • Spas operate on 240-voltage power. Using the multimeter tool, if the meter reads 240 volts, the problem could be the heating element. If it reads 0, it may be the circuit board that needs checking.

  • Spas operate on 120-voltage power. The same steps are taken to determine what could be the problem. If the reading is 120 volts, it could be the heating element that needs to be replaced. On the other hand, if it reads 0, the culprit could be the circuit board.

Another way to test if the heating element is faulty is through an OHMs test (impedance test). This testing method identifies the resistance of the element.

  • Step 1: Make sure the spa is turned OFF.
  • Step 2: Unplug the heater element's copper tabs (or wires).
  • Step 3: Switch the multimeter setting to OHM.
  • Step 4: Test both leads on the heater element.
  • Step 5: Check the reading. If the reading shows 9-14 OHMs, the heating element is more likely not the problem. However, if the meter doesn’t show any reading, the issue might be the heating element.

If you are not comfortable performing these tests you should request a licensed electrician or spa technician to assist you.

What to do if the heating element is not working?

If after testing the heating element you determined it is faulty, please do not attempt to repair or replace the heater. The risks of electrical repairs are high, especially around water. We always recommend hiring a licensed electrician or spa technician.

The technician will probably ask you to choose whether you want the entire assembly replaced, or just the heating element. They might suggest replacing the entire heater assembly if it’s a few years old.

Should you need help finding a suitable replacement, email us the photo of your heater or heater element here.

The touchpad display on your spa can alert you with different error messages that help you identify if there is a problem with your spa. If your spa fails to heat the water, check the touchpad display as there might be alerts that require you to take action. Error 3 and Error 4 are the common problems or alerts you might receive.

Your spa has entered economy mode.

If you have a hot tub in economy mode, you may wonder how to switch it back to standard mode. Economy mode is a useful feature that helps to reduce energy consumption and save on operating costs, but it may not be suitable for all situations.

What does an economy mode do on my hot tub?

Running a hot tub or spa pool can be expensive in terms of electricity and maintenance costs. That's why many spas come equipped with an economy mode.

The economy mode on a spa is a setting that helps to reduce energy consumption and operating costs. When you switch your hot tub to economy mode, it uses less energy to maintain the water temperature.

When the economy mode is turned on, the spa pool’s heater will run intermittently, rather than continuously. The hot tub will turn on the heater for a short period to heat the water and then turn it off to maintain the water temperature. This helps to minimise the amount of energy used by the heater, making your hot tub more energy-efficient.

It is important to note that the economy mode may take longer to heat up your hot tub compared to the standard mode. This is because the heater is not running continuously. It is advisable to turn on the economy mode a few hours before you plan to use your hot tub to ensure that the water is hot enough.

How do I get my hot tub out of economy mode?

To get your hot tub out of economy mode, please follow the steps below.

Step 1: Locate the Control Panel

The first step is to locate the control panel on your hot tub. The control panel is usually located on the side of the hot tub or near the top. It contains several buttons and controls that allow you to adjust the settings of your hot tub.

Step 2: Turn off the Economy Mode

Once you have located the control panel, you need to turn off the economy mode. The process of turning off the economy mode may vary depending on the model and manufacturer of your hot tub. Typically, you will need to press and hold a button that says "economy" or "ECO" for a few seconds. This will switch your hot tub back to the standard mode.

Step 3: Adjust the Temperature

After turning off the economy mode, you may need to adjust the water temperature to your desired setting. To do this, locate the temperature control button on the control panel. It is usually labelled with an up and down arrow. Press the up arrow to increase the temperature or the down arrow to decrease the temperature.

Step 4: Wait for the Hot Tub to Heat Up

Once you have adjusted the temperature, you need to wait for the hot tub to heat up to the desired temperature. This may take a few hours, depending on the size of your hot tub and the temperature outside. It is important to note that the hot tub's heater will switch on and off intermittently to maintain the water temperature.

Step 5: Test the Water

After the hot tub has reached the desired temperature, you need to test the water to ensure that it is safe to use. Use a water testing kit to check the pH and chlorine levels of the water. The pH should be between 7.2 and 7.8, and the chlorine level should be between 1 and 3 ppm.

In conclusion, getting your hot tub out of economy mode is a simple process that can be done by following these steps. Remember to adjust the temperature, wait for the hot tub to heat up, and test the water before using it. If you are unsure about how to switch your hot tub out of economy mode, it is best to consult the manufacturer's manual or contact a professional hot tub technician.

Your set temperature has been reached.

Most spas are built with electronic or digital controls to set the desired water temperature. One of the features of these spa controls is enabling users to set a specific temperature for their spa.

If your spa is not heating as it typically does, you might have accidentally set the temperature low (or maybe a child fiddled with the temperature setting) then the heater may have turned off when the set temperature was reached.

Tip: To avoid children from fiddling with your spa display, you may lock the spa keypad to learn how to do this.

How to know if the set temperature for a spa has been reached?

The display of your spa can show the current and set water temperature of your spa. If you set the default display mode of the keypad to water temperature, you’ll easily know what temperature the water is at and what temperature it is set by just looking at the display. Please note that not all spas are built the same. Please refer to your user’s manual.

How to adjust the temperature of a hot tub?

The steps in adjusting the spa temperature may be different depending on the brand of control system your spa has. To guide you in adjusting the temperature of your spa, we are going to use one of the most popular control systems in Australia, the SpaNet™ control keypad.

  • Step 1: Press and hold the up or down arrow.
  • Step 2: Once the display flashes the current temperature of the spa, this means you can now start adjusting the temperature.
  • Step 3: Push the up and down buttons until it reaches your desired temperature.
  • Step 4: Press the OK button to confirm the changes.

Watch: Spa-Net SV Spa Controller Instructions

The maximum temperature has been reached.

To protect the users from the potential health risks of overheating, spas have set a maximum temperature which is 40°C (104°F). When the spa has reached the maximum temperature, it will stop heating. In some cases, the keypad display may show it has reached the maximum temperature but the water isn’t as hot as it should be.

An uncalibrated thermostat, malfunctioning spa heater, inefficient spa cover, bad sensors, and very low outdoor temperature are some of the possible reasons why this could happen.

To determine what might be the problem, we recommended having a registered technician examine your spa.

How hot can a spa get?

In general, spa temperatures range between 32°C (90°F) and 40°C (104°F).

The U.S. Consumer Product Safety Commission (CPSC) recommends that water in the spa shouldn’t exceed 40 degrees Celsius (104 °F). The World Health Organization also states that water temperatures exceeding 40°C may pose risks to your health.

What temperature should a hot tub be?

You can make your spa as enjoyable and therapeutic as possible by following the recommended temperature.

  • Healthy adults. The recommended safe temperature for adults without health conditions is between 37°C (100°F) to 40°C (104°F).
  • Pregnant women. Medical professionals advise pregnant women to keep their body temperature below 39°C, especially during the first trimester, as higher temperatures can lead to birth defects like brain and spinal cord issues.
  • Seniors. The warm water may help relieve joint and muscle pains which are common in most elderly. The ideal temperature for seniors is between 36°C and 100ºF, not exceeding 39°C or 102ºF. We highly recommend seniors with health conditions (especially those taking medication) consult their doctor before using a spa or hot tub.
  • Kids. Young children should not be allowed in hot tubs until they are able to stand on the bottom and keep their heads above water, according to the Pool & Hot Tub Alliance (PHTA). Kids tall enough to use a spa should not stay in more than five minutes if the tub is at 104ºF (40°C). If the temp is at 98ºF (37°C), they can extend their stay, but not beyond 15 minutes.


In this article, we discussed the 5 possible causes of spa heating problems and shared a step-by-step guide on how to fix them. We also shared helpful hot tub temperature tips to ensure a safe and therapeutic spa experience.

Disclaimer: All electrical work should be carried out by a licensed electrician or spa technician.

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