Gestra NRS1-3b Level Switch

Issue Date: 3/06
GESTRA Steam Systems
Product Range B1
Level Switch
NRS 1-3b
NRS 1-3
Description
Technical Data
Two-channel low-water-level alarm with test button in conjunction with the GESTRA multiple level-control
electrode type ER... or level-control electrode type
ER 16.
Application in steam boiler plants to TRD 401 and TRD 602.
Type-approval no.
TÜV·WR/WB·03-302
Function Type-approved two-channel level switch with test button in conjunction with the multiple level-control electrode type
ER... or level-control electrode type ER 16/NRG 16-4.
Design Plug-in unit in plastic case for installation in control cabinets. The terminals in the case are accessible after
loosening two screws and unplugging the unit from its base. To avoid confusion with other plug-in units of the
GESTRA range, inserts are fitted in the bases so that only the correct unit may be plugged into each base.
The plug-in units may be snapped onto a 35 mm supporting rail or screwed into position on a mounting panel.
Field enclosures for several plug-in units are available on request.
Note:
TÜV·WR... applies to NRS 1-1, 1-2, 1-5, TÜV·WB... applies to NRS 1-3;
combinations of water-level controllers (WR) and low-level alarms (WB) are possible due to the type
approval Input 2 connections for one electrode tip Output 2 potential-free relay contacts mounted in series;
max. contact rating: 250 V, 500 W, 3 A resistive with a life of 4 x 105 switching cycles or 0.35 A inductive with a life
of 2 x 106 cycles;
contact material silver, hard-gold plated Sensitivity 10 µS/cm (other values available on request)
Electrode supply voltage 11 V AC, free from DC voltage Indicators and adjustors
2 LEDs “low-level alarm (LW)” 1 “Test” button for checking electrical circuits
1 “Reset” button for resetting burner-protection circuit after “lock-out” (the connection of an additional push
button on site is possible; by removing the wire link the reset button is without effect)
Mains supply 24 V, 110 V, 120 V, 220 V, 240 V, 50... 100 Hz, 3.5 VA (please state voltage when ordering),
24 V DC supply also possible with the ancillary unit type URN-1 Protection
IP 40 Permissible ambient temperature 0... 50 °C Case materials Base: ABS plastic, black
Cover: polystyrene (highly shock-resistant), stone grey Approx. weight 0.8 kg
Level switch NRS 1-3b