Smart Sauna Sensor & MyHarvia 2 app - Troubleshooting
Page content
- Connection problems
- Login and account problems
- Why Smart Sauna Sensor and Fenix control panel show different temperatures?
- User manual
Connection problems
Cannot connect to WiFi
- Make sure the WiFi network you're connecting to has a strong signal.
- Move the router closer to your sauna. The walls of the sauna room may significantly block the Wi-Fi signal.
- The network frequency must be 2.4 GHz. Smart sauna sensor does not support 5.0 GHz network frequency.
- The network name (SSID) cannot contain any special characters.
- The WiFi module requires access to port 8883 (secure MQTT), which must be opened in the firewall. Additionally, there must be access for Network Time Protocol (NTP) servers. Also check that other ports are not blocked, especially 443, 8443 and 8883.
WiFi connection interruptions
- WiFi signal is too weak. Move the router closer to your sauna if you experience connection interruptions. The walls of the sauna room may significantly block the Wi-Fi signal.
Outdated information in MyHarvia 2 app
- The information displayed in MyHarvia 2 app - such as the WiFi signal strength or sauna temperature - is based on the most recent sauna session. The latest information is always updated during your next sauna session.
- The sensor will not turn on or update any information displayed in the app if the sauna room temperature is below 40 °C, or if no movement has been detected in the sauna during the last 60 minutes.
Login and account problems
MyHarvia 2 app login problems
- Cannot log in to MyHarvia 2 app or password recovery is not working: User account has not been created or may have been deleted → Create a new user account.
Why Smart Sauna Sensor and Fenix control panel show different temperatures?
Many sauna users notice that the temperature readings on the MyHarvia Smart Sauna Sensor and the Harvia Fenix control panel can differ significantly, especially while the sauna is heating up. The difference can temporarily be as much as 10–20 °C. In most cases, this is completely normal and does not mean that either sensor is measuring incorrectly. To understand these differences, it is helpful to first consider how heat behaves in a sauna and why these two sensors are designed for different purposes:
The temperature in a sauna is not the same everywhere. Unlike in many indoor spaces, the temperature in a sauna is not distributed evenly. During heating, significant temperature differences develop in the sauna, both vertically and across different parts of the room. For this reason, two sensors located in different spots may display completely different temperatures at the same time, even though both are measuring correctly.
Why Smart Sauna Sensor and Fenix control panel show different temperatures?
The simple answer is that they are intentionally measuring different things:
Fenix ensures safe operation of the sauna heater
Fenix sensor is located above the stove, at the ceiling line. This is the hottest spot in the sauna. The sensor’s primary function is to control the heater and ensure safe operation. The sensor also includes an overheating protection feature designed to detect potential hazards as quickly as possible. This is precisely why the sensor must be installed above the stove, at the ceiling line. If the sensor were placed in a cooler location, it would no longer be able to monitor the heater’s operation as intended.
Smart Sauna Sensor measures the thermal environment of the sauna
MyHarvia Smart Sauna Sensor is installed according to the instructions, approximately 20 cm below the ceiling on the wall opposite the heater. The purpose of this location is not to control the heater but to measure as accurately as possible the thermal environment in which the sauna user is actually located. The temperature measured by the sensor typically better reflects the heat felt around the sauna user’s head and shoulders than the measurement taken by a control sensor located near the ceiling.
Why are temperature differences highest during the heating phase?
During the initial phase of heating the sauna, thermal equilibrium has not yet been reached. The heater heats the air quickly, but the walls, ceiling, benches, and other structures are still cool. At this point, the air near the ceiling heats up significantly faster than the rest of the sauna. At the same time, the stove is by far the strongest source of heat radiation. As a result:
- Fenix sensor located at the ceiling edge heats up quickly.
- Smart Sauna Sensor heats up more slowly.
- Temperature stratification is at its strongest.
- Differences in heat radiation across the sauna are at their greatest.
For this reason, a temperature difference of 10–20 °C during heating is a completely normal occurrence in many saunas.
When might a large temperature difference indicate an incorrect installation?
During the heating phase, a temperature difference of 10–20 °C is often completely normal. However, it’s a good idea to check the installation if:
- Smart Sensor is not on the wall opposite the sauna heater.
- Smart Sensor has not been installed at the height specified in the instructions.
- Fenix sensor is not located above the sauna stove, at the edge of the ceiling.
- The sensors are directly exposed to the water.
- There is particularly strong airflow near the sensor.
User manual
Download MyHarvia Smart Sauna Sensor user manual from the link below:
Let's sauna