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What is the best Way to Test A Hot Tub Heater?




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If there is one part of your hot tub that you don’t want to break, it’s the heater. It’s not called a hot tub for anything.

Even if you live somewhere incredibly hot, sitting outside in a cold tub of water is not pleasant. 

So, if you have recently found yourself sitting in a pool of lukewarm water, it’s a good idea to test your hot tub heater. 

There are a couple of reasons why your hot tub heater might be playing up. So here’s our guide to checking all of the potential causes.

Plus a few tips and tricks for making sure your hot tub is always in good working order and at its best.

Safety Warning

Just before we get started, there are a few safety measures to consider. Your hot tub heater will be electric and testing anything electrical yourself can be dangerous.

Especially when the electric system is combined with water (such as in a hot tub). So, if you don’t feel 100% confident about testing your hot tub heater, we suggest that you call in a professional.

If you are feeling confident then the number one safety rule is: shut off the power. This is the rule for pretty much any electrical work. Make sure that everything is turned off before you get started. 

This can save you from any accidental damage to both yourself and your hot tub. Your hot tub is supposed to make you more relaxed and the risk of an electric shock is definitely not relaxing!

hot tub in winter

Testing Tips

Okay, now we’ve got that out of the way, here are a few ways to test your hot tub heater yourself.

As mentioned above, testing your hot tub heater is a pretty professional process. So you’re going to need some kit. 

Testing your hot tub heater involves testing the electrical current. So you’re going to need an Ohm meter. You can find these for relatively affordable prices online.

Check the Heating Elements

Your hot tub heater is made up of several different elements. The specifics of the system will depend on the brand, style, and technical capabilities of your hot tub.

But here are the basic steps for testing the heating elements:

  1. Make sure everything is powered off.
  2. Remove the copper tabs or disconnect the wires that are on the heating element terminals. 
  3. Set the Ohm meter to the lowest setting
  4. Take the tips of the Ohm meter testing leads and place them on the tips of the element terminals.
  5. Take the reading.

This might seem simple but you still need to know exactly what you’re doing and where to look. You also need to know what to look for.

A good reading will be around 10-14 Ohms. Anything less than this means that there is not a strong enough resistance. This could be the case if your hot tub is heating up slowly.

If there is a reading of zero, then your heater likely needs replacing. This reading will be caused by damage to part of the heating element.

Check the Thermostat and Temperature Controls

This might seem obvious but it’s worth double-checking. If you’re having trouble with your hot tub heating up, the problem might not be with the heater itself.

So it’s also worth checking the temperature controls.

The temperature controls on your hot tub will vary depending on how old it is. Some very old hot tubs have manual dial thermostats.

Whereas more modern hot tubs have simple up and down arrows or a digital temperature display.

If your hot tub is a good few years old, then it might have a manual thermostat. If it does, try altering the temperature significantly.

The Heater and The Pump

If the temperature of the water doesn’t change or is slower than normal to heat up, then the problem could be with the thermostat. 

If you know what you’re doing, then you can take the thermostat off the hot tub and check the wiring.

But if you’re not used to working with electric wires, then we recommend you call an electrician or a hot tub technician. 

Top Tips

So, now that you know the best way to test your hot tub heater. But how can you keep things in good working order generally?

There is a lot of information around that tells you the best way to clean and maintain your hot tub.

But not very much of it relates to the technical side. So here are a few more tips on how to keep the electrical aspect of things running smoothly. 

  • Keep track of what you remove. When testing your hot tub heater, you’re going to need to remove a few different components. Before you begin unscrewing or dismantling anything, make sure to look over the instruction manual (if you still have it). This will give you a detailed diagram with labeled components. Keep this with you as you work. It will help you if you get confused and forget in which order you took things apart. 
  • Positioning. It’s more than likely that your hot tub was installed by a professional. And they likely chose the best placement for your hot tub. So, one of the best things you can do to ensure a good electrical supply is to leave it there. It’s easy to forget about the electrical side of a hot tub. But, without electricity, it’s simply a big cold bathtub in your backyard. So, even if you have found a sunnier spot in your garden, it’s best to still leave your hot tub where it is.


So, that’s the easiest way to test your hot tub heater. It’s not the most complicated process.

But it is still something that should be left to a professional electrician if you’re not feeling confident about safety measures. 

But, if you are feeling confident (and know your way around all the parts of a hot tub) then this should be a pretty easy job for you. Just always remember to shut the power off first!

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