Hot Tub High Limit Switch Location (Troubleshooting)

In this guide, we are going to talk about hot tub high limit switch location and troubleshooting. It can be immensely frustrating when you lift the cover of your hot tub, all ready to jump in, only to realize that the water is still cold in your hot tub.

Most people get angry because of this, but there’s not a lot to worry about. Instead of thinking the worst, you may want to look at the high limit switch. It may have tripped, thus preventing your hot tub from overheating altogether.

Most hot tub owners are not exactly aware of the switches and components that work underneath. For those who don’t know, a high limit switch is essentially a simple switch that’s added to hot tubs for safety reasons.

When the switch is flipped, it simply deactivates the heater when the temperature of the water goes higher than it should have. This is designed to prevent the hot tub from overheating and eventually causing a fire.

There are several reasons why this temperature sensor may flip. First of all, you need to find the appropriate reasons before you think about troubleshooting the whole thing.

Hot Tub High Limit Switch Location

Most people don’t bother looking for the high limit switch as long as their spa is working fine, and why would they? Most of us don’t bother tinkering with their hot tubs as long as everything is going smoothly.

However, when something happens to the switch and you realize that the water is cold, your mind may start wondering what’s happening.

To make things easier for you, the following paragraphs contain a lot of information about the temperature switch, and the steps you need to take to fix the problem.

A high limit switch is generally located in the heater enclosure. It’s most commonly found in the lower left corner of your enclosure, and is usually white in color. You will identify it thanks to a distinct red button that’s situated in the center.

When the water isn’t heating up properly, it’s important that you check the limit switch before you start checking other things.

Hot Tub High Limit Switch Troubleshooting

The high limit switch has a built-in circuit breaker that automatically breaks the circuit so that electricity doesn’t reach the heater. Here are some of the many reasons why the switch may flip.

Trapped Air

If you recently drained out and refilled your hot tub and noticed that your high limit switch starts tripping, it’s probably due to an air lock in the internal system.

When air is trapped inside the pipes of your hot tub’s plumbing, it could interfere with the flow of water that passes through the heater.

As a result, the heater may receive less water than it needs, or it may not get any water at all. Needless to say, the heater heats up more than it should, and as soon as this temperature spike is detected by your light switch, it trips.

This is designed to prevent a breakout of dry fire that could not just damage the equipment, but is likely to cause serious damage to the environment as well.

Therefore, the first thing that you need to do is get rid of all the trapped air in your hot tub. To do that, you may want to bleed the water valves.

When the air escapes, you will hear a hissing sound coming from the valves. Once that is done, tighten the valves again, and then see if it trips.

A Dirty Filter

The filter in your hot tub is designed to keep all of the contaminants and dust particles out of the water in your hot tub. If you haven’t cleaned the filter in a long while, it is likely to cause the temperature switch sensor to flip.

When debris clogs up the filters, the overall water circulation is slowed down considerably. As a result, the heater doesn’t receive the maximum amount of water that it should to operate at optimal levels.

This ultimately reduces the rate at which water flows from the jets as well. As a result, the spa skimmer installed in your hot tub doesn’t receive enough water either.

Ultimately, it starts sucking up the air instead of water, which could ultimately cause damage to the heater. Instead of heating up the water, the heater starts heating up the air.

To fix this problem, you may want to start by removing the filter and then cleaning it as thoroughly as possible. Make sure that there is no dirt or debris on the filter before you fix it back in.

Once you clean it, just plug it back in and then flip the switch. See if that solves the problem.

Corrosion on the Heater

Another major cause is corrosion on the heater. Corrosion could prove to be disastrous for your hot tub, and it could cause the limit switch to flip as well.

If the problem is caused by rust, it’s easy to identify. You may want to closely look at the wiring, or just take out the component board and see if the internals are all corroded.

If rust has eaten away the circuitry or the internal components, your only option is to buy a replacement. It’s going to be expensive, but you absolutely need to invest in one to prevent major problems down the line.

Issues with the Thermostat

Is the thermostat working properly? There’s a possibility that the calibration on the thermostat is all wrong, and as a result, it might not be giving out the right temperature.

You may want to re-calibrate the thermostat by checking the instructions from the owner’s manual. This will make it easy for you to determine whether the issue is caused by the thermostat or not.

Try all of these fixes and then see if that resolves the issue. As long as you do everything by the book and don’t go over the top with your tinkering, you should be fine!

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