Steca TR 0502 U

5 inputs, 2 outputs


The Steca TR 0502 U controller was developed specifically for the North American market as a variant of the basic Steca TR 0502 controller. Special approval (ETL mark) via a testing laboratory recognised in the United States as an NRTL (Nationally Recognized Testing Laboratory) means that the relevant safety standards and minimum requirements of the North American market have been met.

In the installation housing, the device connection is created either as a plug & play solution for grid and pump connections or alternatively with 1/2 inch apertures.

This controller offers everything required to operate your solar thermal system safely and continuously. The Steca TR 0502 U controller 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 large graphic display shows animated control loops to visualise the operating states of the respective system. The clear display guarantees easy operation through the consistent use of pictograms. Pre-programmed equipment systems enable universal use. Steca TR 0502 U has five inputs for temperature or pulse detection and two partially speed-controlled outputs for controlling pumps or switching valves.

Steca TR 0502 U technische Zeichnung


Product features

  • Compact, multipart designer casing
  • Electronic speed control
  • High level of operational safety through fault diagnosis
  • Hours-of-operation logger
  • Software update possible
  • Storage tank target temperature loading
  • Daily pump start
  • Plug & play for 120 V AC mains and pump connections in installation casing
  • Screwed connections facilitate fast sensor installation
  • Integrated Steca TPC 1 bus


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


  • Multilingual menu navigation
  • Side switch for manual, auto, off


  • Installation casing with 1/2 inch cut-outs as an alternative to plug & play


  • Heat quantity (Grundfos Direct Sensors™, pulse generator, determination)
  • Heating return increase
  • Reduction of stagnation phases
  • Holiday (storage tank recooling)
  • Circulation (controlled by temperature / time / pulse)
  • Back-up heating
  • Solid fuel boiler
  • Storage tank quick charge
  • Thermostat
  • Differential thermostat
  • Timer
  • Interval / tube collector
  • Anti-freeze
  • Display storage tank top
  • Alarm output
  • Two loading zones


  •  Steca TR 0502 U productdatasheet DE · pdf · 0,953 MB
  •  Steca TR 0502 U productdatasheet EN · pdf · 0.953 MB
  •  Steca TR 0502 U manual EN · pdf · 5.985 MB
  •  Steca TR 0502 U product pic drawing · jpg, 300 DPI, high quality · 0.590 MB
  •  Steca TR 0502 U product pic drawing · jpg, 72 DPI, web quality · 0.292 MB

Technical data

 TR 0502 U
System voltage
120 V AC, 60 Hz
System voltage optional
240 V AC, 60 Hz
1.57 W [0.003 HP]
Temperature control class
Energy efficiency
1 %
Number of inputs
4 x temperature (Pt1000), 1 x temperature (Pt1000) or pulse
Additional inputs
1 x Grundfos Direct Sensors™ (temperature / flow rate)
Number of outputs
1 x triac for speed control (R1), max. 230 W / 0.3 HP (120 V AC); 1 x switch output relay (R2), max. 400 W / 0.5 HP (120 V AC) or R2 voltage free
Additional output
1 x alarm output
Line cord
75 inch, 3 x 18 AWG at 221 °F
Hydraulic schemes
Ambient temperature
0 °C [+32 °F] … +45 °C [+113 °F]
RS-232, RS-485 (Steca TPC 1 bus)
Degree of protection
IP 20 / DIN 40050
Dimensions (X x Y x Z)
170 x 178 x 90 mm [6.69 x 7.00 x 3.54 inch]
1400 g [45.01 oz]
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