Steca Solar Controls
steca solar controller

Steca 301U

3 Inputs
1 Output


The Steca model TR0301U temperature differential controller provides for the automatic, safe, and reliable operation of domestic solar water heating systems. The control output is wired to a pump that circulates the heat transfer fluid between the solar thermal collectors and the storage tank during the course of the day. This microprocessor-based control utilizes two RTD type sensors to monitor collector and tank temperatures with digital accuracy.

The LCD gives the homeowner a variety of real time information including system temeratures at up to three separate locations. The consistent use of simple pictograms ensures ease of operation and troubleshooting. In addition to the primary function of turning the circulating pump on and off during the day, the TR0301U provides important diagnostic and safety functions. For example, the LCD pictograms will indicate fault conditions such as sensor shorts or pump failure. The installation manual also clearly describes the fault symptoms, possible causes and remedies.

The control features a total of three inputs and one 120 VAC output for the circulating pump. Varistors protect the sensor inputs against high voltage spikes. The load side is fuse protected. The control package includes two RTD type (resistance temperature detector) sensors, a seven foot line cord and a spare fuse. An optional third sensor displays the upper tank temperature and eliminates the need for an analog thermometer and fittings.

The numerous additional features of the TR0301U include an adjustable on/off differential (8 - 20 F) and high limit (32 F - 205 F), an evacuated tube collector function, vacation overheat protection to minimize collector stagnation, and a freeze-recirculation option. Temperatures can be displayed in either Fahrenheit (F) or Celsius (C).


● Digital Accuracy
● LCD Provides Real Time Operating Temperatures At Up To Three Locations
● Animated Representation of System Operation
● Sophisticated Monitoring and Fault Diagnostics
● Fused Output Protection For Pump Circuit
● Varistor High Voltage Spike Protection
● RTD Type 1000W Sensors
● Adjustable On/Off Differential and High Limit
● Evacuated Tube & Freeze Recirculation Functions
● Vacation Overheat Protection
● Accessible Side-Mounted On, Off, Auto Switch
● Three Temperature Sensor Inputs/One 120 VAC Output

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