GESTRA SPECTORcompact – Level Electrodes with Integrated Evaluation
The SPECTORcompact series is applied in steam boilers, pressurized hot water systems, condensate tanks, and feedwater vessels. Unlike systems with separate electronic controllers, signal evaluation is integrated into the electrode head, reducing external modules in the control panel. Proper design of the protection tube or external level chamber remains essential for reliable operation.
Variants and Functionality
- NRGS 11-1 / 16-1: Four-rod electrode with integrated level switching controller for MIN/MAX level detection and pump control.
- NRGS 11-2 / 16-2: Compact controller/limiter with MIN alarm, pump ON/OFF, test, and reset functions.
- NRGS 15-1: Compact PN25 system for low level 1/2, pump control, and high level alarm.
- NRGT 26-1 / 26-2: Continuous level measurement using capacitive principle, analog output 4–20 mA.
Operating Conditions
Conductive compact systems require minimum water conductivity >0.5 μS/cm at 25°C. NRGS 16 is rated up to 32 bar at 238°C; NRGS 15-1 is PN25, 25 bar at 224°C. NRGT 26-2 is PN40, 32 bar at 238°C, with 24 VDC supply, IP65 enclosure, and 4–20 mA output.
Connections and Materials
Standard mechanical connections: G1 A ISO 228 for NRGS, G¾ A or DN50 PN40 flange for NRGT. Wetted parts are stainless steel (e.g., 1.4571), with PTFE electrode insulation.
Standards and Limitations
Compliant with VdTÜV Wasserstand 100, Low Voltage Directive, EMC, and selected UL/cUL certifications. Not suitable for ATEX-classified explosive atmospheres.
Selection Criteria
Selection is based on boiler pressure/temperature, water conductivity, required switching points, relay or 4–20 mA output, electrode length, and installation layout. External level chambers require periodic flushing of connecting lines to prevent blockages.