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Basics of Hot Tub Electronics

Hot tub electronics play a huge role in the functionality and comfort provided by a hot tub. Without these critical components, you would be essentially besitting in a puddle that is room temperature. Hot tub electronics provide the heat, the jets, and the water movement that we’ve all come to love with regard to hot tubs.

Generally speaking, hot tubs are powered by a 240V (volt), 50A (amp) circuit that should be routed through a breaker near the hot tub. This breaker will generally have a throw switch that allows owners to quickly de-energize their hot tub in the case of an emergency. Since this circuit is in the close proximity of water, it should also be a GFCI circuit to prevent electrocution.

Hot tubs contain a number of electronic components that some owners may never see, depending if you’re bold enough to pop the hatch on your hot tub cabinet. Some of these items are obvious, while some may not be so obvious.

As with any electrical and mechanical devices, especially those near in the presence of water, failure is inevitable. Costs of replacement hot tub electronics can range from a few dollars to upwards of $500 depending on the components needing to be replaced.

Now that we’ve gone over the basics of hot tub electronics, let take a look at some common electrical components within a hot tub.

Circuit Boards

Circuit boards are the brain of the hot tub electronics. Similar to a computer, they send signals to components in your hot tub to perform certain actions. Turning on blowers, heaters, and pumps are just a few of the actions initiated by the circuit boards within your hot tub.


A relay is an electronic device that allows you to “switch” a high amount of current. In a typical switched electronic circuit, a switch sits in the middle of the circuit. When the switch is in the off position, it makes the circuit “open” (ie – not connected). When the switch is moved into the on position, it “closes” the circuit, allowing current to flow through the circuit.

This method is fine and dandy when there isn’t a large amount of electricity or current flowing through the circuit. However, for components in a hot tub such as the heater or pump which require a lot of power, a switch in the middle would burn up when exposed to this amount of current. A relay solves this problem by connecting to the switch with a low current, and controlling the open and closed state of the high current circuit.

Spa Packs

Spa packs are the major components of hot tub electronics. Typically spa packs will consist of the pump(s), the heater, the controller, and sometimes the blower. It’s basically the components that are responsible for heating and moving the water – both critical features in a hot tub.

cIt’s not uncommon for these hot tub electronics to go out, and purchasing and installing spa packs are a typical maintenance procedure when it comes to spa ownership.


Some model hot tubs have analog timers. These are similar to those old egg timers people used in kitchens. You rotate the dial to a set amount of time, and the hot tub pump will typically run for this amount of time. Once the timer is up, the pump shuts off. These timers can sometimes come in handy if you’re the type to turn your hot tub pump on and forget to turn it off (it’s happened to all of us!).

Top-side Controls

Top-side controls are the hot tub electronics that interface with the users. Users can set the temperature of the water, turn the jets on or off, and perform other functions depending on the hot tub’s make, model, and features.

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