How Do I Know If My Heating Element Is Bad In My Hot Tub?


In order to find out whether the heating component, a part of it, or a completely unrelated section is causing the hot tub heating element any issues, proper and careful testing is required. The hot tub owner is required to take action and perform several steps of testing to reach an accurate conclusion.

Before getting started with the testing phase and identifying the potential cause of the issue, shutting all power to the hot tub at the service panel is an absolute necessity. This ensures no dangerous accidents happen during the tests and/or repairs, that should only be performed by a qualified engineer. Fully disconnecting the power from the spa is also highly recommended.

  • Step: To test if a heater issue is caused by a tripped breaker, disconnecting the copper wires from the spa pack, leading up to the heater element is a good place to start. Once the power is turned back on – if the breaker also stays on, it identifies the fact that the heater is malfunctioning.

The solution to this problem is to identify the element of the heater that needs to be replaced and do so immediately.

  • Step: Spas and hot tubs may operate on a 240 voltage power, or 120. In case the hot tub heater is not bad or malfunctioning (not tripping), but the hot tub still has no heating, a voltage test is next in line. It‘s performed with a multimeter that measures voltage. The test is performed while the hot tub or spa is running, with both leads on the element simultaneously.

For 240 voltage spas and hot tubs, if the meter reads 240 volts, it can be concluded that the issue is in the element itself. However, if the meter is reading 0 volts, the circuit board is the culprit.

For 120 voltage hot tubs and spas, the same test is carried out and the same results are expected. If the multi-reader is showing 120 volts, the element is faulty, but if it is showing 0, again, the circuit board is not functioning properly.

  • Step: Alternative testing methods – another efficient and popular way the heater‘s functionality is tested, is by performing an OHMs test (Ohm – unit for measuring electrical resistance). This test is designed to determine if the electrical resistance of the element is working.

It‘s completed in 4 phases:

  • Phase A: All power to the hot tub is turned off.
  • Phase B: Copper wires (tabs) connected to the heater element are disconnected.
  • Phase C: The multimeter is set to the OHM setting.
  • Phase D: Both leads on the heater element are tested.

In case the multimeter shows a measurement of 9 to 14 OHMs, the element itself is not the issue. But, if the reading on the multimeter is 0 or “open”, the heating element is bad and not working properly.

How do you test a hot tub temperature sensor?

Testing spa or hot tub thermometer sensors and ensuring they work properly is extremely important. Testing the hot tub or spa temperature sensors is performed in separate steps.

1. Step – all power to the breaker and hot tub needs to be shut off;

2. Step – Set the OHM meter to 20K setting;

3. Step – Locating the end of the wires and removing the plug from the board

4. Step – Placing the meter leads onto the red and green wires

5. Step – Comparing the meter readings to Thermistor Resistance against the Temperature Chart.

Thermistors are called hot tub high limits and most of them have a reading of 10 thousand at 77° Fahrenheit (25° Celsius). Colder water produces higher readings (up to 50 thousand) and warmer water a lot lower readings. In case the reading is at 0, either the cable or the sensor is bad. Hot tubs usually have more than one temperature sensor. They can also have a water temperature sensor, an air sensor and a heater temperature sensor.

How do I reset my hot tub thermostat?

Hot tubs are known for their hydrotherapy, providing a soothing environment by pumping and circulating water in through pumps and jets and regulating temperature. A hot tub thermostat is a heater that regulates the desired temperature of the hot tub user. It may need to be reset if it has stopped working completely or tripped and there are steps on how to properly reset it.

1. Step – Locating the high limit hot tub reset button, that is usually red in colour. It might be located on the heater itself and covered with a rubber nipple.

2. Step – Pressing the high-limit reset button. When pressed, it will “click” in when it is reset.

3. Turning on the hot tub again and observing it work. If there‘s no power, a breaker panel switch may have tripped or a GFCI (Ground Fault Circuit Interrupter) outlet.

4. Rest the GFCI outlet by pressing the reset button on it or flip the break panel switch to restore power again. When turning on the spa again, if the heater element fails again, it most likely needs to be replaced and that was the main issue.

What to do if the hot tub is overheating?

Although owning a hot tub can be quite a blessing, especially in the midst of the summer, during the hot, long days, there is always the danger of overheating if certain precautionary measures.These measures include:

  • 1. Step: Turning off the hot tub as soon as you spot the issue of overheating. Most hot tubs have an automatic shutdown system, if the temperature reaches 112 degrees Fahrenheit or 44.4°C.
  • 2. Step: calling the dealer or the manufacturer regarding service options. Different hot tub brands and manufacturers may offer different customer service options.
  • 3. Step: Checking the water level in the hot tub. Low water levels can and often lead to overheating, so adding more water may be a simple solution for the problem.
  • 4. Checking the valves in the hot tub. If they are closed while the hot tub heater is on, it may cause significant issues with overheating.
  • 5. Cleaning the hot tub filters. If filters are not regularly kept clean, they may block the flow of water and cause it to overheat.
  • 6. Turning the power back on after finding out what exactly the problem was, after talking to the hot tub dealer. The hot tub will probably not start back up until the water reaches a safe temperature.

Why does my hot tub temp keep going down?

There are several reasons that can cause the temperature in a hot tub to drop down, most of them pointing to other, perhaps more serious issues. Such reasons include:

  • A faulty part, perhaps a failed heater
  • A low speed of the water circulation indicating an issue with the hot tub pump
  • The pressure switch or the hot tub‘s thermostat may not be working properly

An indicator that the temperature in the hot tub is not regulated nor maintained in a proper manner can be a high fluctuation of the water temperature. This means that the water flow is causing a fluctuation more than a few degrees inside the hot tub.

A good example of this issue would be if, for the sake of argument, the temperature on the thermostat is set to 103 degrees, but the water is falling below 100 degrees before the heater has started to work at all. It can happen vice versa, of course. For example, the temperature rising over 105 degrees before the hot tub heater has begun to work.

However, before taking any action, it is important to establish if the control panel of the hot tub is showing accurate temperature readings from the thermostat. A faulty thermostat is one of the most common parts that are not functioning properly, so ruling this matter out needs to be considered a priority.

Once this has been completed and it is confirmed that there are no issues with the thermostat, the owner can move on in determining what exactly is causing the drop in temperature of the hot tub water.

The following components need to be thoroughly checked and have their accuracy confirmed:

  • The hot tub water flow, meaning checking the filters to see if anything is interrupting their functionality;
  • The test switch, as well as any other switches included in the hot tub working system. This can include a pressure switch, a high-limit switch for the temperature, a pressure switch, also known as the flow switch, or any other switch that‘s a part of the system;
  • Sensors for the heating system or any other kind that can affect proper functioning;
  • Additional (other) factors, such as loose connections between the parts of the heating system, hot tub cover used for insulation from outside temperatures, plumbing lines and other relevant components and circumstances.

How do I know if my hot tub circuit board is bad?

The first signs of a faulty circuit board are usually the obvious ones, such as damaged cables, plug-ins that don‘t work, or lack of any screen on the display, located on the top side of the panel. In order to make sure the circuit board is not working, one can try turning off the spa and turning it back on. If there is still no response, the issue is with the circuit board.

Sometimes resetting the hot tub can resolve the issue, but if the circuit board is not functioning, it will not be helpful. Issues with the circuit board can be related to the electrical current coming from the source, but there are also several factors that may be included. The top side of the board may be faulty, moisture could have gotten to a sensitive part inside. On occasion, part of the circuit board can overheat, burn or even melt. One of the ways of identifying the problem is checking each wire with a meter.

However, the best thing to do before getting started on trying to resolve the issue yourself, is to call the manufacturer. The manufacturer will be able to provide some simple guidelines on how to check everything regarding your circuit board safely and thoroughly.

How do I know if my hot tub fuse is blown?

Checking if the fuse is blown requires disconnecting the power from the hot tub circuit entirely. Once this is completed, the fuse is tested with an Ohm meter. There are proper test for checking spa fuses:

  • 1. Step – it requires shutting off the power completely to the hot tub;
  • 2. Step – Setting the Ohm meter to 1K setting
  • 3. Step – Remove the fuse from its housing or the board, depending on where it is located;
  • 4. Step – Placing each of the meter leads on each end of the fuse;
  • 5. Step – Comparing the readings from the meter to the ones printed

In case the meter is showing the sign of infinity, it means that the fuse is entirely blown.

For testing purposes, one can use a voltmeter/multimeter, that is set on resistance. If the fuse is properly working, it should show a reading of 0, but if not, then it will stay at 1. It is important to remember that fuses degrade over time and will inevitably fail at some point. The very purpose of the fuse is to conduct electricity to a certain (pre-determined) level, so if that level has been surpassed, the fuse will blow. It is actually a precautionary measure to prevent an electrical shock.

Also, some hot tubs have an internal fuse system that is designed to blow when the voltage of the currency spikes. Checking the manual of the hot tub manufacturer in order to locate and inspect the internal fuses is always a prudent step.

In cases where the fuse is blown, replacing it with a brand new one is the right solution to this problem.

Is there a reset button on a hot tub pump?

Depending on the make and model of the hot tub, most models have a high-limit reset button. It is usually a red button, located on the heater and covered by a rubber nipple.

In order to successfully reset the hot tub pump, it is recommended to watch a video regarding a thermal reset.

The resetting process begins by turning the pump units on. Afterward, the test button is pressed once and left bleeping for about 10 seconds. Then, the pump unit is turned off and unplugged from the socket and kept that way for about 10 seconds. Plugging the pump back in and turning it back on will complete the reset process.

During the time the pumps work, one should always look out for any humming noises, possibly coming from the engine not turning, or whining noise from worn bearings. Leaks under a pump from potentially damaged pump seals are also always an issue.

How low can you set the temperature on a hot tub?

Although many hot tub owners may not be aware of this, the hot tub can work on lower temperatures as well. Most brands produce hot tubs that can work on as low as 80 degrees Fahrenheit – 26.7 degrees Celsius.

This setting is usually used during the hot summer months when the owner wishes to cool off by taking a refreshing bath inside a cool hot tub. Setting the hot tub on the lowest possible temperature basically turns the heaters off completely.

However, it is not recommended to keep the hot tub below 90 degrees Fahrenheit (32 degrees Celsius). There are other ways to cool down your hot tub that will not affect the minimum setting of the temperature.

  • Aside from dropping the temperature of the water in the hot tub, these ways include:
  • Keeping the cover off – it acts as a sort of insulator, preserving the temperature of the air and water below it, so removing it will allow fresh air to cool down the water;
  • Running the jets on a two-hour cycle also helps, causing the water to circulate
  • Dropping ice (this actually does not cause any issues with the hot tub) into the hot tub water also helps to cool it down
  • Increasing the frequency of water circulation by keeping the filters as clean as possible. Cleaning them twice a week should ensure the best circulation possible;
  • Having additional products to the hot tub, such as a Cool Zone, that is located just outside the hot tub and the water inside is as low as 60 degrees Fahrenheit (15.5 degrees Celsius)

The desire to keep the hot tub water cool during sunny, hot months of the summer is not uncommon and many hot tub owners use some of these pointers to help them enjoy a refreshing, cooling bath during summertime.

Editorial Staff

I'm Adnan Sabanovic, the guy behind Hot Tubs Report. I've had a chance to enjoy hot tubs last few years and have really become interested in owning one of them. Nearly every weekend you'll find me spending time with my family or playing sports. If I am not doing that then I'm here writing about tubs on Hot Tubs Report. This blog is a research for my first hot tub which I decided to document and share publically so others can benefit from it as well.

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