ESR21 R3 Solar controller—Relay output

The ESR21-R3 is easy to use and install for single circuit solar systems for domestic hot water or swimming pools. Part # 01/ESR21R3

The ESR21-R 3 is a differential control unit which has been consciously made easy to install and operate. Its wide range of controls makes it useful in a multitude of applications: with solar thermal systems for domestic water and swimming pools, water heater loading, ventilation control, burner requirements with a holding circuit, air flap control for earth collectors with a temperature window, etc.

• All of the switch-on and switch-off points can be set separately

• Clear display with icons for all of the values displayed

• Status display for immediate recognition of extraordinary conditions

• Solar start function

• Pump blockage if collector overheats

• Anti-freeze function

• Heat meter

• Use of 3 temperature sensors of types KTY (2 k?) or PT1000

• Overvoltage protection at all inputs

• Very easy to install and operate

• Min/Max thresholds -20 to 150deg.C

• Differential temperature 0 to 99deg.C

• Accuracy typ.+/-2%

• Operating voltage 230 V AC 50-60HZ

• Power Consumption max. 3VA

• Rated current load 1.5A resistive-inductive cos phi 0.6

• Transformer short circuit proof 

Controller Manual