Level Electrodes (Limiters) - SPECTORconnect | Gestra

GESTRA SPECTORconnect – Level Electrode Limiters

The GESTRA SPECTORconnect level electrodes are designed for use in steam boilers and hot water systems as level limiting devices. Measurement is based on water conductivity: the electrode rod is detected as immersed or non-immersed, with the switching point determined by rod length.

Operating Versions

• NRG 16-60 / 17-60 / 19-60 / 111-60: Low-level limiter. If the water level drops below the LW threshold, the URS 60 / URS 61 unit triggers an alarm and interrupts the burner/heating circuit.
• NRG 16-61 / 17-61 / 19-61 / 111-61: High-level limiter. If the HW threshold is exceeded, water supply can be interrupted or a control valve closure command can be issued.

Technical Specifications

• Connection: G¾ A EN ISO 228-1 for NRG 16/17/19, G1 A for NRG 111
• Pressure classes: PN40, PN63, PN160, PN320
• Typical limits: NRG 16 PN40 32 bar at 238°C, NRG 19 PN160 100 bar at 311°C, NRG 111 PN320 183 bar at 357°C
• Supply voltage: 24 V DC ±20%
• Power consumption: up to 7 VA
• Ingress protection: IP65
• Conductivity range: 0.5–10,000 μS/cm (most versions)
• Communication: CANopen via CAN bus ISO 11898
• Operation/indication: URB 60 or SPECTORcontrol

Standards and Safety

When combined with URS 60 / URS 61, the electrodes are integrated into a safety circuit up to SIL 3 according to EN 61508. Compliance with PED 2014/68/EU, Low Voltage Directive, EMC, and RoHS is documented.

Installation Points

Installation is vertical or at an angle up to 45°. For inclined mounting, rod length is limited to 1000 mm. External level pots require regular flushing of connecting lines and use of SRL 6-60 for monitoring flushing time and sequence.

Maintenance

Inspection includes checking for rod deposits, insulation loss, connection tightness, CAN bus faults, and alarm logs. Do not remove the electrode under pressure or at elevated temperature.