Yacht Sauna Reaches Excessively High Temperature

On saunas installed on yachts and charter vessels, temperature control is particularly delicate due to factors such as vibrations, marine humidity, and voltage fluctuations. Keeping the heater under control is essential not only for comfort but also for safety. If the sauna reaches abnormal or excessively high temperatures, it usually means that the heater remains on without proper regulation. In most cases, this malfunction is caused by issues with the temperature sensor (thermistor), which does not accurately detect the actual cabin heat.

 

1. Check the sensor position

Correct positioning of the temperature sensor is crucial to ensure the heater regulates heat properly. The sensor should be:

  • Height: 160 cm (5 ft 3 in) from the floor
  • Position: Always on the wall opposite the heater; never above or near the heater
  • Distance from ceiling: At least 20–30 cm (8–12 in)

An incorrect position can produce false readings, causing the heater to continue warming unnecessarily and leading to cabin overheating.

 

2. Sensor may be burnt

A burnt sensor no longer reads the actual temperature, causing the heater to stay on continuously. In this case, the sensor must be replaced by a qualified electrician, since replacement involves:

  • disconnecting wiring
  • checking cable continuity
  • installing a new sensor

On many yacht saunas, the sensor may be housed in a metal channel or protected by wooden slats. If the cable is easily removable, replacement is quick; otherwise, part of the wooden lining may need to be removed to access the sensor.

 

3. Sensor may be oxidized

On boats, salt and humidity can oxidize sensor contacts, especially if the sauna has been off for weeks or months. Signs of oxidation include:

  • sauna temperature rises quickly above the set level
  • heater switches off and on irregularly
  • display shows incorrect readings

Action:

  • gently clean contacts with anti-oxidation/contact-cleaning spray
  • check the sensor for damage or deformation
  • inspect the connection to the control unit terminals

 

4. Other possible causes of overheating on a yacht

Beyond sensor-related issues, sauna overheating on a yacht may result from:

  • insufficient internal ventilation in the sauna cabin
  • malfunctioning or disconnected safety sensors (overheat protection)
  • overheated or oxidized cables along the display–heater path
  • voltage fluctuations from onboard generators
  • incorrect internal lining (panels not suitable for sauna use) that traps excessive heat

 

Technical assistance for yacht saunas

For maintenance, diagnostics, or original spare parts, Centro Italia Yachting offers specialized technical support for saunas installed on yachts and vessels. The team provides fast, professional interventions to ensure your sauna remains efficient and safe.

You can contact the service via the toll-free number in Italy 800 931 931 or, from abroad, at +39 327 612 0605. Thanks to Centro Italia Yachting, every intervention is carried out using certified spare parts and with technical expertise specific to the marine environment.