Maximum Level Switches NGX

1. INTENDED USE
   The maximum level switch NGX with TÜV design approval (certificate No. 968/EL 743.00/11) is designed to protect compressors within a refrigeration plant against liquid hammer (e.g. to conform with TRAS110). The maximum level switch is not suitable to be used as a minimum level switch or level switch.
2. RANGE OF OPERATION
   The mechanical operated NGX can be used on surge drums and liquid receivers and is suitable for all common refrigerants with a density ρ of at least 600 kg/m³. Even when electrical level switches are installed, the use of the design-approved NGX, to switch off the compressors, is mandatory.
   3. SCOPE OF DELIVERY (STANDARD)
   Sensor NGX with junction box
   Brackets to connect the NGX to the 1“ of the stop valve
   Stop valve EA 32 – G1“-I
   Relay BNRt (for installation in the switch gear, see installation instructions W 4651-6.11-)

         Optional
         Stop valve in stainless steel
Socket connection G 1“-NGX (when used with foreign valves)

4. Detail
   A) Switch
   Housing material: 1.4571
   Balancing bar: PTFE/
   Connection: G 1“ outer thread
   Pressure- / Temp.-Range: PB 25 bar / +80°C to –50°C
   Weight: 0.6 kg
   B) Junction box
   Material: Aluminum
   Dimensions: 63 x 58 x 40 mm
   Protection Class: IP 65
   Connections: 2 x PG 9
   Weight: 0.36 kg (Junction box with brackets)
   C) Brackets
   Material: PP – black
   Dimensions: 60 x 71 x 30 mm, hole appr. ø 42 mm
   With EA 32 /G1” or EA 40/G1” valve
   D) Reed-Contact
   Voltage: 14 V AC/DC
   Current: max. 0.5 A
   Cycles: 1000 / s
   Contact: Rhodium

5. DESCRIPTION OF OPERATION
   The switching activating point is located in the center line. Therefore the center line of the maximum level switch
   determines the maximum level in the vessel that is used for the control. In the NGX housing there is a balancing
   bar, which consists on one side of PTFE and on the other side there is a magnet fitted (these are the only
   materials in contact with refrigerant). When the refrigerant level rises within the surge drum to the connection of
   the NGX, the PTFE float will get in contact with refrigerant and start to drift up. The magnet on the other side of
   the balancing bar will move downwards. A reed-contact that is installed outside of the refrigerant surrounding will
   recognize the position of the magnet and will open when about 4mm are passed in the bottom position. The
   signal will be transferred through the relay BR-NWt and an auxiliary contactor within the switchgear to the compressor control.
   An LED display connected in series with the reed-switch is illuminated during normal operation. If the LED is not
   illuminated the following reasons might occur:
   The maximum level in the surge drum has been exceeded
   The power supply was interrupted (cable breakage or misconnected cable)
   The reed-contact is defect
   The magnet has been contaminated (with metal particles).

          Note: The NGX cannot be connected directly to a SPS control. (If the wiring diagram as shown on page 3 of the installation instructions of the BR-NWt W 4651-6.11 is modified, the design approval is void)