TDC Solar Controls

Temperature difference controllers by SOREL: versatile and user-friendly. Thanks to the clear operator guidance, various types of solar systems can be operated intuitively – from small to complex.



“Small” Temperature Difference Controller for simple systems for 9 solar, storage and solid fuel boiler-systems



“Medium” temperature difference controller for medium-sized systems for 25 basic systems with switchable functions for unused relays



“Large” temperature difference controller for larger solar systems for 42 basic systems with switchable functions for unused relays



Xtra large for flexible controlling of complex solar thermal systems with up to 4 storages

Midsize Temperatur Differenz Controller für einfache Solar-Systeme


Midsize temperature difference controller for simple solar systems with electronic roof heating up to 3 kW.

Large Temperatur Differenz Controller für einfache Solar-Systeme


Large temperature difference controller for simple solar systems with electronic roof heating up to 3 kW and circulation pump control.

Pool TDC M


Solar Pool Controller

Pool TDC M


Solar pool controller with filter pump running time control

Advantages of SOREL solar controls

Full text menu

Clearly understandable, context-sensitive help texts explain each setting value.

Setup Wizard

Guides step by step through all necessary settings for quick and easy commissioning.

Graphic display

Animated visualisation of the system, clear characteristic curves and energy statistics.

Modular principle

The systems can be flexibly expanded by activating additional functions using free relays.


Various menu languages can be freely selected for clear communication.


Free Windows software simplifies training, functional testing and technical support.


Controllers can be networked via CAN bus or connected to the Internet.

0…10V/PWM outputs

For speed control of high-efficiency pumps.

Data logging

Via Micro SD card for storage and evaluation of system data.


For internet connection via the data logger or for system optimisation through communication with our system controllers.

Sensor inputs PT1000346834
Relay outputs 230V123612
Relay output voltage-free111
Outputs 0..10V or PWM signal
for speed control of high-efficiency pumps
Number of applications925+42+48+48
Extension of pre-defined systems
by selectable additional functions
LEDs red/green for display of operating status
Statistics and graphic analysis of data memory
Flow based heat metering via Grundfos direct sensor (VFS / VVX)22
Pressure monitoring via Grundfos direct sensor (RPS)22
Battery-backed Real Time Clock > 24h
Time and Temperature-controlled thermostat function
Legionella function via solar
Legionella protecion via additional heating
Cooling function
Setup wizard
System protection
Collector protection
Storage protection (CP Tmax)
Anti-freeze protection
Start logic for vacuum tube collectors
Control program for self-dumping systems (drain-back)
Function control and error memory with date and time
Menu blocker
Power supply for universal voltage range (100…240VAC) and reduced standby consumption
CAN bus connection for SOREL Connect
Data logging on microSD cardvia data loggervia data logger
Ethernet connectionvia
data logger
via data logger✓(only at V2)
Dimensions Height x Width x Depth in mm115 x 86 x 45163 x 110 x 51163 x 110 x 51228 x 180 x 53163 x 110 x 51163 x 110 x 51
Housing colourRAL 9003RAL 9003RAL 9003RAL 9003RAL 9003RAL 9003
Protection ClassIP40IP40IP40IP40IP40IP40
Mounting Hardware, Spare Fuse and User Manual



The setup wizard guides you quickly through the settings to be made in a logical sequence. This prevents incorrect settings and facilitates parameterisation.


The current measured values and operating states are displayed in an animated overview. In addition, important functions are shown as symbols in the display.


Settings with full text – Explanations

Relay assignment

Additional functions: Relay selection

Relay function

Selection of the Additional functions

Relay setting

Setting the Additional function Thermostat


Functional control and long-term monitoring of the system is made possible by recording and evaluating the data.


Graphical evaluation Legend

  • Temp. difference
  • Pressure monitoring
  • Heating circuit
  • Always On
  • Booster pump
  • Error message

  • Antilegionella
  • Storage transfer
  • Cooling
  • Return flow increase
  • Reheating
  • Solid fuel boiler

  • Antilegionella
  • Storage transfer
  • Cooling
  • Return flow increase
  • Solar bypass
  • Parallel operation

MTDC System 1 + Solar Bypass


Solar with storage with additional function Solar Bypass

LTDC System 14 + solid fuel boiler

LTDC_solid fuel boiler

Solar with heat exchanger with additional function Solid fuel boiler

XTDC System 20 + additional heating


Solar with 2-zone storage and switching valve with additional function thermostat (additional heating)


PC Simulation

Virtual simulators of any SOREL controller are available free of charge for easy product trial, technical trainings or to facilitate your customer support.

Request Simu

Where to buy

Find your national SOREL contact person or the nearest SOREL retailer:

Find contact person