Technische Alternative ESR 21 Series

Questions and Answers

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Andrew JamesAug 3, 2025
Why is my Technische Alternative ESR 21 displaying incorrect temperatures?
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  Darrell CummingsAug 3, 2025
  If your Technische Alternative Control Unit shows values like -999 (sensor short-circuit) or 999 (interruption), it doesn't automatically indicate a hardware issue. Ensure the correct sensor types (KTY or PT1000) are selected in the menu under SENSOR, as the default setting is PT (1000). To check the sensor, replace the potentially faulty sensor with a known working one on the terminal strip to verify the display.
A
agarciaAug 12, 2025
What to do if my Technische Alternative ESR 21 Control Unit system is not in operation?
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  Stanley FisherAug 13, 2025
  If your Technische Alternative Control Unit isn't working despite having power, check the 3.15A quick-blowing fuse that protects the control system and the output. Replace the fuse if necessary.
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Kristina DeanAug 23, 2025
How to troubleshoot a malfunctioning Technische Alternative ESR 21 Control Unit with realistic temperature values?
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  joshua47Aug 23, 2025
  If your Technische Alternative Control Unit is malfunctioning but displaying plausible temperatures, consider these checks: * Verify the program number. * Examine the switch-on and switch-off thresholds and the set differential temperatures to see if they've been reached. * Check if settings in the submenus have been altered. * Test the output in manual mode to ensure it can be switched on and off. If it responds correctly during an endurance run, the unit is likely in order. * Confirm that all sensors are connected to the correct terminals. You can test a sensor by heating it with a lighter and observing the display.

Summary

Hydraulic Diagrams

Program 1

Details about program 1 for solar thermal systems with an additional storage limit.

Sensor Installation

Sensor Lines

Information on sensor line cross-sections, extension limits, and connection methods.

Installing the Device

Instructions for physically mounting the control unit and connecting internal components.

Electrical Connection

Data Link (DL)

Details on the bi-directional data link for PC communication and compatible hardware.

External Sensors

Instructions for reading external sensors via the DL connector.

Safety Requirements

Operation

The Main Level

The Parameter Menu Par

Changing a Value (Parameter)

The Menu Men

Status Display Stat

Tips on Troubleshooting

EU Declaration of Conformity

Technische Alternative ESR 21 Series Specifications

General

Housing Material	Plastic
Connection Type	Screw terminals
Number of Relays	4
Number of Analog Inputs	4
Inputs	Digital, Analog
Outputs	Relay
Display	LCD
Humidity	non-condensing
Relay Contact Rating	230 V AC
Analog Input Type	0-10 V, 0-20 mA