Sauna Controller with Evaporator

Sauna controller with Evaporator
Using this Function Block, a Sauna with an Evaporator can be intelligently automated
All standard Sauna heaters can be controlled (switching of the heating elements, as well as analog control via 0-10 V signal).
An Evaporator can be switched On / Off, but also controlled via an analog 0-10 V signal.

Table of Contents


Abbreviation Summary Description Unit Value Range
Mode Select sauna mode 0 = Off / Manual
1 = Finnish manual
2 = Humidity manual
3 = Finnish sauna
4 = Herbal sauna
5 = Steam bath
6 = Hot-air bath
- 0...6
Fim Finnish manual - 0/1
Hum Humidity manual - 0/1
Fin Finnish sauna - 0/1
Her Herbal sauna - 0/1
Sof Steam bath - 0/1
Hot Hot-air bath - 0/1
Tg Toggle Toggles between Sauna On, Heating, Drying, Fan, Sauna Off. - 0/1
ϑt Target temperature Min: 30°C
Max: 110°C (Finnish manual)
Max: 70°C (Humidity manual)
ϑc Current temperature °
Ht Target humidity % 15...65
Hc Current humidity % 0...100
Fan Toggle fan Switches fan on / off.
The fan can only be switched on when the sauna is On.
- 0/1
St Activate sand timer Activates the sand timer for the duration set in parameter (Std).
Each subsequent pulse on the input restarts the timer.
- 0/1
Dc Door contact The door state is only used for display in the user interface! - 0/1
ϑb Current temperature bench If connected, the bench temperature is used as current temperature. °
P Presence Used for safety shutdown.
If no presence is detected, the sauna will shutdown automatically after the duration set in parameter (Ssdt).
- 0/1
Ws Water shortage If the water supply is low, the Evaporator is switched off. - 0/1
Off Off Pulse: Outputs are reset / switched off.
On: Block is locked.
Dominating input.
The name of the connected sensor is used in the user interface.
- 0/1
DisPc Disable periphery control Disables inputs (Tg), (Fan), (St) when On. (e.g Child lock, cleaning)
Control via user interface is still possible.
- 0/1
On On Activate Sauna - 0/1


Abbreviation Summary Description Unit Value Range
So Sauna output (0-10V) Analog output 0-10V for sauna control. -
L1-3 Sauna phase output (1-3) Phase output (L1-3) for sauna control. - 0/1
Ev Evaporator output (0-10V) Analog output 0-10V for Evaporator control. -
Evd Evaporator digital output Digital output for Evaporator control. - 0/1
On Sauna state On as long as sauna and drying phase are active. - 0/1
Fan Fan Output for fan control. - 0/1
Stt Sand timer remaining time s 0...∞
Dry Drying phase - 0/1
Mode Current sauna mode 0 = Off / Manual
1 = Finnish manual
2 = Humidity manual
3 = Finnish sauna
4 = Herbal sauna
5 = Steam bath
6 = Hot-air bath
Ssd Safety shutdown Pulse when the temperature exceeds the value set in parameter (Ssdϑ). - 0/1
ϑt Target temperature Outputs the target temperature. °
Ht Target humidity Outputs the target humidity. % 15...65
Stoff Sand timer end Pulse when the sand timer ends. - 0/1
St Sand timer state On when sand timer is active. - 0/1
Ready Sauna ready Pulse when target temperature is reached. - 0/1
AC API Connector Intelligent API based connector.
API Commands
- -


Abbreviation Summary Description Unit Value Range Default Value
ϑd Temperature deviation Deviation current temperature to seat temperature (if the input current bench temperature (ϑb) is not used). ° 0
Dryϑ Drying phase temperature The temperature required to start the fan when in drying phase. ° 70
Dryd Drying phase duration Fan duration after reaching the drying phase temperature (Dryϑ). s 0...∞ 1800
Std Sand timer duration s 0...∞ 600
Ssdϑ Safety shutdown temperature If exceeded, all outputs are switched off, except for the output (Ssd). ° 139
Ssdt Safety shutdown time The sauna is automatically switched off at the set time.
If input (P) is used, the time starts to run when presence is no longer detected.
s 0...∞ 7200
PWMp PWM period Specifies the PWM period for the phase outputs (L1-3). s 0...∞ 180
G Gain Controller gain for the PWM modulated output.
If the value is decreased, the temperature control responds slower, if it is increased, it responds faster. If necessary, change the value in small steps to adapt the control to the sauna.
- 0...∞ 1
Pm Phase mode Number of phases used:
0 = 3 phases
1 = 1 phase
2 = 2 phases in Evaporator mode or 3 phases in mode without Evaporator.

Parameter is only displayed if phase outputs (L2) and (L3) are used.
- 0...2 2


Using this block, a Sauna can be Automated Optimally. All common sauna stoves can be controlled. (Switching of the Heating Elements, as well as Analogue control via 0-10V Signal). Also integrated in the block is a Sand Timer function, Airing, and Drying. There is also a Safety Shutdown, if you forget to switch off the heater. You can choose between different Operating modes such as: Hot Air Bath, Herbal Sauna, Finnish Sauna, etc… In Addition, the Sauna module can be operated via the Web Interface/App and, therefore, remotely. Please ensure you follow the relevant Safety and Legal Regulations for your respective Country.

Basic Programming

The sauna temperature sensor is linked to input (ϑc) and the humidity sensor to (Hc).

The output (So) and the phase outputs (L1-3) are used to connect the respective outputs. If the sauna heater requires only one phase, use (L1). The fan is connected to output (Fan).

Phase outputs (L1-3) are pulse-width modulated by the controller to emulate an analog value. For example, a value of 20% means that the outputs are on for 20% of the period and off for 80%.

The steam generator is connected either to the output (Ev) (analog 0-10V) or to (Evd) (digital on/off) depending on the type of control.

No Remanence

For security reasons, the block has no remanence.
Therefore, it is always switched off after a Miniserver restart.