Steca TF A603 MC+

Fresh water controller (stand-alone)


The Steca TF A603 MC+ is a stand-alone fresh water controller for heating domestic hot water directly and hygienically using the instantaneous water heater principle.

Thanks to an innovative control algorithm, the Steca TF A603 MC+ controller is able to transfer the energy of a buffer storage tank to the domestic hot water circuit particularly quickly and efficiently. Already after the first commissioning, the self-learning control algorithm of the controller synchronises itself with the individual conditions of the respective system, ensuring a constant domestic hot water temperature from a hygienic perspective.

This is done primarily with the aim of achieving the lowest possible return temperature to the buffer tank in order to further increase the efficiency and yield of a solar system. This is supported by the function of a zone feeding of the buffer storage water using a 3-way switching valve.

The Steca TF A603 MC+ can also control a circulation pump. The controller offers time, temperature or pulse dependent control methods for this purpose.

As a special highlight, the Steca TF A603 MC+ stores the operating data of the system on an SD card. The large graphic display shows the animated control loops to visualise the operating states of the respective system. The Steca TF A603 MC+ has six inputs for temperature or pulse detection as well as an additional Grundfos Direct Sensors™ input for combined temperature and flow measurement. Three partially speed-controlled outputs are used to control pumps and switching valves.

Note: The Steca TF A603 MC+ is only available in conjunction with a fresh water station approved by KATEK.

Steca TF A603 MC  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
  • Daily pump start
  • 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


  • Auto-adaptive control algorithm
  • Data logger on SD card
  • Heat quantity (Grundfos Direct Sensors™, pulse generator)
  • Circulation (controlled by temperature / time / pulse)
  • Back-up heating
  • Thermal disinfection
  • Alarm output


Product data sheet

  •  Steca TF A603 MC+ productdatasheet DE · pdf · 0,996 MB
  •  Steca TF A603 MC+ productdatasheet EN · pdf · 0.996 MB

Product pics, technical drawings, etc.

  •  Steca TF A603 MC+ product pic 3D · jpg, 300 DPI, high quality · 1.379 MB
  •  Steca TF A603 MC+ product pic 3D · jpg, 72 DPI, web quality · 0.436 MB
  •  Steca TF A603 MC+ product pic · jpg, 300 DPI, high quality · 1.251 MB
  •  Steca TF A603 MC+ product pic · jpg, 72 DPI, web quality · 0.374 MB
  •  Steca TF A603 MC+ product pic drawing · jpg, 300 DPI, high quality · 0.517 MB
  •  Steca TF A603 MC+ product pic drawing · jpg, 72 DPI, web quality · 0.263 MB

Technical data

 TF A603 MC+
System voltage
230 V AC (± 15 %), 50 Hz
System voltage optional
115 V AC (± 15 %), 60 Hz
Own consumption
≤ 2 W
Number of inputs
5 x temperature (Pt1000), 1 x temperature (Pt1000) or pulse
Additional inputs
1 x Grundfos Direct Sensors™ (temperature / flow rate)
Number of outputs
2 x triac for speed control (R1, R2), max. 250 W (230 V); 1 x switch output relay (R3), max. 800 W (230 V) or R3 voltage free
Additional output
1 x alarm output or backup heating requirement
Ambient temperature
0 °C … +45 °C
SD card, RS-232, RS-485 (Steca TPC 1 bus)
Data logging
SD card
Degree of protection
IP 20 / DIN 40050
Dimensions (X x Y x Z)
170 x 170 x 46 mm [0.00 x 0.00 x 0.00 inch]
450 g [0.00 oz]
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