SGC26H Differential Regulator
Differential controllers SGC26H

Differential controllers SGC26H

SGC universal differential controllers are designed to control solar water heating systems and to support space heating. Advanced operating algorithms ensure optimum utilisation of solar energy and enable the control of energy-saving circulators. SGC controllers have pre-set hydraulic schemes built in, allowing quick and easy set-up.


  • in domestic hot water heating systems with conventional or vacuum collectors,
  • in domestic hot water heating systems with supplementary heat sources,
  • in storage tank heating systems with solar thermal and supplementary heat sources,
  • in pool heating systems.
Solar Collectors

Advanced settings for switching on an additional source of domestic hot water heating when there is insufficient solar energy

The SGC26H, SGC36HV and SGC67HV differential controllers have advanced settings for switching on an additional source of domestic hot water heating when solar energy is insufficient:

  • the possibility to set the heating of the domestic water with an additional source to a minimum temperature (yes/no options),
  • the option to switch on the additional source of domestic hot water immediately or only when the collectors cannot heat the domestic hot water to the desired temperature within a certain time,
  • Determine the time interval during which only collectors are allowed to heat domestic water. The controller will not switch on an additional source if it calculates that it can heat the domestic water to a temperature outside the desired temperature within this time interval.

Setting up a domestic hot water heating timer

The SGC Differential Controller allows you to set up timer programmes for heating sanitary water. You can set when the system heats the water and to what temperature. The time programme can be adjusted as and when needs change. This way, you will have heated water exactly when you actually need it.

Holiday mode of operation

When you go on holiday, you can switch on the holiday mode, which will heat the water to a minimum temperature, or switch off the water heating. The holiday mode is set for the period of your holiday or extended absence from home. If we set the duration of the holiday programme to heat the tap water for a few hours before we return home, we will have the tap water heated to normal temperature when we return home and we will not even notice that the system has been switched off during the carnal period.

One-time instantaneous switch-on of sanitary water

If you need heated water outside of normal heating hours, you can switch on the one-time heating of the water. The controller will switch on the heating, heat the tap water and then continue heating according to the normal timing programme.

Display of the energy generated from a solar system

Differential controllers are typically used in solar water heating systems. The controller keeps track of how much free energy has been recovered. You can view the data archive in a graphical display for a weekly monthly or yearly period.

Displaying the Energy Generated from a Solar System

Smart Control via Mobile App

Smart control via mobile app

SGC controllers can be connected to the SeltronHome platform, which allows you to remotely control heating management via smartphone or tablet. Remote control is possible via the CLAUSIUS app for the end user and the KELVIN app for the installer. For example, the app can be used to activate the once-through heating function for domestic hot water outside the timed programme, if required.

Key features of the SGC26H differential controller

  • 22 preset hydraulic schemes,
  • 1 output for free programming,
  • speed control of 1 conventional pump (RPM),
  • speed control of 1 energy-saving pump (PWM, 0-10 V),
  • regulating systems with 2 collector fields,
  • regulating systems with 2 heat sinks,
  • the possibility to regulate heating systems with a solid fuel boiler,
  • a wizard to start your device quickly and easily,
  • measuring and displaying the energy generated,
  • Protecting the solar system when the collectors overheat,
  • notifications of activated safety functions and warnings of system faults,
  • the ability to simulate sensors and analyse system performance,
  • remote monitoring using SeltronHome.
In domestic hot water heating systems with conventional or vacuum collectorsYesYesYesYes
In domestic hot water heating systems with supplementary heat sourcesYesYesYesYes
In storage tank heating systems with solar thermal and supplementary heat sourcesNoYesYesYes
In swimming pool heating systemsNoYesYesYes
For one-step filling of the storage tankNoNoYesYes
For two-stage filling of the storage tankNoNoNoYes
Number of preset hydraulic schemes5225365
Number of mechanical relaysNo114
Number of electronic relays1122
Number of inputs for temperature sensors6667
Number of collector fields1222
Number of storage tanks1233
Measuring the energy generated (kW/h)YesYesYesYes
Flow measurement option with pulse meter (l/min)YesYesYesYes
Flow measurement option with Vortex VFS sensor--YesYes
Speed control for energy-saving pumps (PWM, 0÷10 V)1 pump1 pump2 pumps2 pumps
Speed control for conventional pumps (RPM)1 pump1 pump2 pumps2 pumps
Free programming option-1 exit2 exit3 exit
With collector fields1222
With heat storage1up to 2up to 3up to 3
Heating domestic hot water with a solar thermal system and an additional heat sourceNoYesYesYes
Heating supportNoYesYesYes
Heating the poolNoYesYesYes
With solid fuel boilerNoNoNoYes
Quick start function for cold storageNoNoNoYes
Conventional or vacuum collectorsYesYesYesYes
Solid fuel boilerYesYesYesYes
Solid fuel boiler with pellet heaterNoYesYesYes
Liquid fuel boilerNoYesYesYes
Combined boilerNoYesYesYes
Gas-flow boilerNoYesYesYes
Heat pumpNoYesYesYes
Heat storageYesYesYesYes
Heating with an electric heaterNoYesYesYes
The controller has the possibility to determine whether the additional source heats the water to a minimum temperatureYesYesYesYes
Possibility to determine whether the primary energy source is switched on immediately or only when the collectors cannot heat the water within a certain period of timeNoYesYesYes
Possibility to set the time to allow the water to warm up collectors only - the controller will not switch on the primary heat source if it calculates that only collectors can heat the water within the set timeNoYesYesYes
Continuous operation in "OPTIMAL" mode means optimum use of solar energy to heat all storage tanks, taking into account the priority storageNoYesYesYes
AUTO mode automatically switches between winter, summer and a predefined calendarNoYesYesYes
Continuous operation in "SUMMER" mode means heating only the priority storage tank, the other storage tanks are heated only when it reaches the desired temperatureNoYesYesYes
Continuous operation in "WINTER" mode means alternating parallel heating of all storage tanksNoYesYesYes
Heating of all storage tanksNoYesYesYes
Heating of domestic water according to a timed programmeYesYesYesYes
Holiday mode of operationYesYesYesYes
One-time - instant start of domestic hot water heatingYesYesYesYes
Legionella protection (for regulated energy source)YesYesYesYes
Protection against freezing of collectorsYesYesYesYes
Forced pump switch-on at maximum collector temperatureYesYesYesYes
Switching off the collectors when the safety temperature is exceededYesYesYesYes
Protecting the solar system when the collectors overheatYesYesYesYes
Overheating protection for the storage tankYesYesYesYes
Reverse cooling of the storage tank to the desired temperatureYesYesYesYes
Periodic start-up of pumps during inactive periodsYesYesYesYes
Graphical display of temperatures by day for the last weekYesYesYesYes
Detailed display of temperatures for the current dayYesYesYesYes
Archiving and graphical display of solar energy dataYesYesYesYes
Notifications of activated safety functions and system fault warningsYesYesYesYes
Possibility to simulate sensors and analyse system performanceYesYesYesYes
USB connection to PCYesYesYesYes
Connectivity to the SeltronHome platform, allowing remote control via smartphone or tabletYesYesYesYes
Wizard for easy and fast device start-upYesYesYesYes
13 language user interface EN, DE, FR, NL, PL, ES, SL, IT, CS, LT, GR, HU, HRYesYesYesYes
Setting the operation by selecting the hydraulic schemeYesYesYesYes
"Help" key for quick help with settingsYesYesYesYes
Graphically configurable time programmesYesYesYesYes
Possibility to simulate system operationYesYesYesYes
Logging and displaying changes to settingsYesYesYesYes
Ability to retrieve basic settings in case of loss or unwanted changesYesYesYesYes
Possibility to programme free outputsYesYesYesYes
Wall or DIN-rail mountableYesYesYesYes
Easy installation and connectionYesYesYesYes
Illuminated graphic displayYes
Operating hours counterYes
Weekly programme hourYes
Connection voltage230 V ~, 50 Hz
Own consumption2,5 VA
Standby power consumptionMax. 0.5 VA
Number of entrances6 x temperature sensor (Pt 1000)
1 x pulse input
Additional inputs1 x Grundfos VFS flowmeter
Number of outputs1 x Triac speed control (R2) 1 x PWM or analogue 0÷10 V (Y2)
Relay outputs4 (1) A ~, 230 V ~
Triac output1 (1) A ~, 230 V ~
Clock power supplyBattery CR2032 (Li-Mn) 3 V
Time display accuracy+/- 1 s (24 h) at 20 °C
Degree of protectionIP20 / EN60529
Safety classI according to EN 60730-1
Type of operation1B to EN 60730-1
Type of temperature sensorsPt1000 or KTY10
Housing materialASA - thermoplastic
Permissible ambient temperature0 ÷ 40 °C
Storage temperature-20 °C ... +65 °C
Weight400 g
Number of pieces per packing unit6 pieces

Electrical connection
Electrical Connection SGC26H

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