My hot tub doesn't get hot, or not hot enough

You turned your spa on yesterday, but the water still remains warm, or even cold? You might have a heater problem, but other - often more simple - reasons can also be the source of the problem. We'll explain, step by step, how to identify the cause of these malfunctions.

We strongly recommend that you call a qualified electrician or technician to carry out electrical operations. If in doubt, contact us.

First of all, check your control panel

Is there an error message?

If the answer is yes, refer to the manufacturer's instructions for use, or our page (this page for Gecko control panels) listing the main error messages that can be found on a control panel, and follow the instructions.

If the answer is no, there is a good chance that the problem comes from the heater if the water remains cold or if the water heats up, but not properly.

The water doesn't get hot

Your heater isn't producing any heat, but there's no error message? This could mean that the resistance in the heater has failed, which means you need to replace the resistance.

A more accurate representation of the problem can be made by comparing the resistance to a bulb, and the continuity between the terminals of the resistance to the bulb filament. The filament is broken: no more lighting. The continuity between the resistance terminals is broken: no more heating.

There are many causes, but most often they are voltage variations in the power lines while your spa requires a stable and constant voltage around 230 V. You may think of an overvoltage during storms, for example, or an undervoltage due to the too long distance between the spa and the electrical panel, if your power cable is too thin.

To determine the value of your resistance, expressed in ohm (symbol: Ω), a multimeter is required.

Always turn off the power to the spa before performing this operation!

If the multimeter indicates a value between the two terminals, your resistance has no problem (the value will be different depending on the power, expressed in kW, of the heater). If the multimeter indicates OL, -- or 0, you must change the resistance (see the video opposite for replacing a resistance)

The water is heating, but too slowly

Your spa is heating up, but the heat is too low and your water remains warm? The problem is not your heater: it either works or does not work, there is no in-between.

On average, a spa gains between 1 and 3░C per hour, depending on its size, insulation, weather conditions, etc. It will not help you to put your hand in front of the heater outlet (or on the heater!) to judge the warming: the water at the heater outlet may be slightly warmer than the pool water, but the difference is so small that you may not notice it.

The easiest way to check whether the heater is heating or not, in addition to determining the value of your resistance with a multimeter, is to measure the voltage, expressed in volts, with the same device.

The power supply to your spa must be on to perform this operation!

If the voltage is around 230 V between the two terminals, and there is continuity (see previous section) your heater is necessarily heating correctly.

Two probable causes then explain the low warming.

  • Your control system only supplies the heater intermittently. An error message will appear (sometimes intermittently, so check it regularly) on your control panel.
  • Your spa is poorly insulated, and therefore loses its heat. The use of a good cover is then essential.