Yacht Sauna Display Shows Incorrect Temperature

The sauna display is essential for controlling temperature, but on yachts it may sometimes show incorrect readings: too high, too low, or fluctuating inconsistently. When this happens, the heater cannot regulate heat properly, resulting in uneven cabin heating. This issue is common on boats, where salt, humidity, vibrations, and long wiring runs can affect sensor accuracy.

Below, we explore the most frequent causes of faulty readings and the checks needed to ensure optimal sauna operation.

 

1. Temperature sensor incorrectly positioned

The most common cause of inaccurate readings is a sensor placed incorrectly. To function properly, the sensor should be located about 160 cm (5 ft 3 in) above the floor, installed on the side opposite the heater, and free from slats or obstacles. It is also important to avoid placing it near air intakes or overly cold areas, which could give misleading readings.

If the sensor is too close to the heater → display shows high temperatures.
If it is too low → display shows low temperatures.

 

2. Oxidized sensor (very common on yachts)

On boats, salt and marine humidity can oxidize the sensor tip, terminals, and contacts behind the display. This shows as rapidly changing values, temperatures rising or falling without reason, or a display stuck on an incorrect value.

Recommended solution:

  • Gently clean contacts with anti-oxidation/contact-cleaning spray
  • Ensure terminals are tightly secured
  • Replace the sensor if the problem persists

 

3. Faulty sensor or damaged internal element

During navigation, vibrations and minor impacts can damage the sensor cable or internal thermistor, affecting sauna operation. Symptoms may include fixed incorrect readings (e.g., 20°C / 68°F or 90°C / 194°F), display not responding to actual temperatures, or the heater shutting off unexpectedly or staying on continuously. The only effective solution is replacing the sensor with a marine-grade model.

 

4. Crushed or broken sensor cable

On yachts, sensor cables often run long distances behind walls or slats, exposing them to accidental cuts during maintenance, crushing by panels or slats, or moisture infiltration in conduits. These issues alter electrical resistance, causing false readings and inaccurate temperature control.

 

5. Display oxidized or damaged by condensation

Condensation inside the display can cause micro-oxidation on buttons or stress the internal fuse. Symptoms include slow temperature rises on the display, numbers changing in steps, or erratic flashing. To fix this, clean the display internally, replace the fuse, and if the issue persists, consider replacing the entire display unit.

 

6. Insufficient ventilation in the sauna cabin

Poor ventilation causes hot air to stagnate, leading the sensor to register incorrect values. Ensure that the lower air intake grille is open, the upper outlet is free, and no objects or panels block airflow.

 

7. Incorrect control unit calibration

Some sauna models require a reset or temperature calibration.

Typical yacht-related causes:

  • Voltage fluctuations when switching from shore power to generator
  • Sudden blackouts
  • Minor generator power spikes

In these cases, a simple reset can often resolve the issue in seconds.
 

When to contact Centro Italia Yachting

If you notice any of the following, contact Centro Italia Yachting promptly:

  • Display shows temperatures that do not match actual conditions
  • Sauna shuts off too early or does not reach the set temperature
  • Heater runs continuously
  • Smell of overheating
  • Visible or suspected sensor damage

For technical assistance or spare parts, call Italy Toll-Free: 800 931 931 or International: +39 327 612 0605. Requests can also be submitted via the Contact page for fast, professional support from a qualified team.