differential thermostat solar water heating pump controller 220VAC 7A with probe

Ideal for home solar water heating system! 220V Version with direct 220V output .
Manufacturer: Deselectra
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Item Description


Ideal for home solar water heating system!

220V Version with direct 220V output . 

Technical data:

  1. Voltage - 220VAC
  2. Temperature range: from 0 C to 90 C
  3. Differential range form   - 0.3  to 50C - set with trimmer.
  4. Direct Output : 7A/250V AC
  5. Sensors - NTC 10K not waterproof.                     

Plate dimensions – 35 x 49 mm.

Length of wires on probes - 25 cm, can be extended up to 15 m. 

Led indication for working load and power on.

Thermostat is not insulated from main supply, so plate is prohibited to be touched with hands, when is live. 

Must be follow the input Live(f) and ground (N).

USE insulated screwdriver to set differential temperature.

Make good insulation of wires when probes are extended.


Method of work - Whenever the Probe 2  is measured to be hotter than the Probe 1 , the output NO contact of the relay close and led come on. The output remains on until the measured temperature difference between the two sensors has fallen depending of the set differential by the trimmer.

Setting differential temperature:

The trimmer needs to be at average position initially. Rotate it at left and right precisely until led go off.

In this way thermostat is set at the lowest differential temperature and is ready for work.

When you rotate it counterclockwise - increase differential temperature. Please note that trimmer is not so precise and small rotating make big change of the temperature between two sensors.  

For example - Probe 1 can be located at the output pipe of hot water boiler and Probe 2 - to Output pipe of the solar panel. The output  can drive 220V up to 10A water pump.

In this way - when solar panel is hotter than boiler - the pump will come on.

When Differential temperature of the two probe come equal to the set by trimmer - the relay will be deactivated.