Question:
We have a Topspa XS where the display shows 37 degrees, but the water temperature is 39–40 degrees. The sensor is installed correctly and is not loose. What could be causing this?
Answer:
If the temperature behaves as described, it is usually because the sensor is not in the correct position or because cold air is entering from somewhere. This cools down the sensor, causing it to not detect the actual water temperature. As a result, the water continues to heat up, and the temperature shown on the display is what the sensor is measuring.
The most common reason cold air enters and affects the sensor is insufficient insulation between the insulated housing and the wall of the spa.
This also leads to higher energy consumption, as the heating does not operate optimally.
This is mentioned in the instructions on page 3, in the third row of images:
Here are examples of what is meant. If you want to make it look “neater,” the edges can be smoothed out and excess insulation foam can be trimmed away.
Insulating between the spa’s bottom insulation and the housing is also important!