Steca TR A502 TT

5 inputs, 2 outputs


The Steca TR A502 TT controller is the ideal solution for all 2-circuit systems. It monitors and controls solar thermal systems with up to two differently oriented collector arrays or a maximum of two domestic hot water or buffer storage tanks.

The Steca TR A502 TT is also characterised by the compact housing typical of this series and can therefore be perfectly integrated into solar stations. Wall or top-hat rail mounting is also possible at any time. Thanks to the variable input voltage range, universal and worldwide use is assured.

The solar thermal controller has five inputs for temperature and pulse detection as well as two outputs. These can be optionally used to control high-efficiency pumps. The equipment also includes an additional alarm output. A graphically animated, clear display visualises the operating states.

The integrated heat meter enables the solar yields to be recorded with imputed values or with the aid of an external pulse generator.

The versatile controller has eleven pre-programmed systems and is extremely easy to configure and operate.

The specially designed switched-mode power supply, the basis for all products in this controller series, also guarantees the highest possible efficiency and economical operation with the Steca TR A502 TT. This is particularly characterised by the extremely low controller self-consumption level. The innovative electronic load control protects against overloading and installation errors.

In order to ensure the continuous and safe operation of the entire solar system, the Steca TR A502 TT takes on important system monitoring and safety functions in addition to the controller operation. Special error messages are displayed for quickly rectifying faults.

Steca TR A502 TT technische Zeichnung


Product features

  • Compact, multipart designer casing
  • Installation versions: Solar pump stations, wall installation, mounting rails
  • Wave packet (Triac) and pulse width modulation (PWM) ensure electronic RPM control
  • High level of operational safety through fault diagnosis
  • Hours-of-operation logger
  • Software update possible
  • Daily pump start
  • Screw terminals allow universal and rapid installation
  • Low power consumption thanks to universal and widerange switched-mode power supply
  • Variable input voltage range for worldwide controller deployment
  • Electronic overloading control and protection


  • Multifunction graphical LC display with backlighting
  • Animated representation of the systems and operating states


  • Non-verbal menu navigation
  • Manual switch for manual, auto, off


  • Heat quantity (pulse generator, determination)
  • Display showing CO2 savings
  • Reduction of stagnation phases
  • Active cooling (e.g. to avoid stagnation)
  • Holiday (storage tank recooling)
  • Circulation (controlled by temperature / time)
  • Back-up heating
  • Solid fuel boiler
  • Storage tank quick charge
  • Thermostat
  • Differential thermostat
  • Interval / tube collector
  • Anti-freeze
  • Display storage tank top
  • Alarm output


  •  Steca TR A502 TT certificate CE · pdf · 0.840 MB
  •  Steca TR A502 TT productdatasheet DE · pdf · 0,946 MB
  •  Steca TR A502 TT productdatasheet EN · pdf · 0.948 MB
  •  Steca TR A502 TT manual DE · pdf · 3.754 MB
  •  Steca TR A502 TT manual EN · pdf · 3.717 MB
  •  Steca TR A502 TT manual ES · pdf · 3.711 MB
  •  Steca TR A502 TT manual FR · pdf · 3.719 MB
  •  Steca TR A502 TT manual IT · pdf · 3.700 MB
  •  Steca TR A502 TT manual CZ · pdf · 3.895 MB
  •  Steca TR A502 TT manual PL · pdf · 3.917 MB
  •  Steca TR A502 TT product pic drawing · jpg, 300 DPI, high quality · 0.453 MB
  •  Steca TR A502 TT product pic drawing · jpg, 72 DPI, web quality · 0.243 MB

Technical data

 TR A502 TT
System voltage
115 V AC … 230 V AC, 50 Hz / 60 Hz
0.76 W
Temperature control class
Energy efficiency
1 %
Number of inputs
4 x temperature (Pt1000), 1 x temperature (Pt1000) or pulse
Number of outputs
2 x triac for speed control (R1, R2), max. 250 W (230 V) or PWM control signal for pump speed (PWM R1, PWM R2)
Additional output
1 x potential-free switching output for the safety extra-low voltage
Hydraulic schemes
Ambient temperature
0 °C … +50 °C
Degree of protection
IP 22 / DIN 40050 [without front panel: IP 20]
Dimensions (X x Y x Z)
110 x 160 x 51 mm [0.00 x 0.00 x 0.00 inch]
350 g [0.00 oz]
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