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5 inputs, 3 outputs

  • For residential and commercial use
  • Ideal solution for double-circuit systems
  • Extremly low own consumption


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



  • Data logging to a MicroSD card
  • Heat quantity (Grundfos Direct Sensors™, pulse generator, determination)
  • Display showing CO2 savings
  • System pressure monitoring (e.g. Grundfos Direct Sensors™)
  • 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 A503 TTR controller

SKU: 364215375135191
  • The TR A503 TTR has two speed-controllable Triac outputs, that can also be configured as PWM outputs for controlling high-efficiency pumps and a relay switched output for additional controller functions. The equipment is rounded off by five inputs for recording temperature and pulses. A specially constructed switching power supply provides maximum efficiency and economic operation. This reduces own consumption to a minimum. The variable input voltage range allows universal use of the device worldwide.

    The integrated calorimetry system allows the acquisition of numerical information on the solar yields of the system. For more demanding requirements, this can of course be expanded using an external pulse encoder or an additional Grundfos Direct Sensors™.

    Steca TR A503 TTR controller monitors and controls solar thermal systems with two differently oriented collector arrays and a maximum of two domestic hot water or buffer storage tanks. The third controller output can be individually customised for additional controller functions.

    Eleven pre-programmed systems enable universal usage. The Steca TR A503 TTR also provides important monitoring and safety functions such as special error messages to quickly troubleshoot faults.

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