WATCHGAS 404/404+

1-4 Channel Gas Alarm

The WatchGas 404 has been designed with features that provide an effective response to the detection of gas hazards in a wide range of environments, from commercial premises through to heavy industrial applications requiring hazardous area sensing. Typical monitor locations are public buildings, boiler plant rooms, swimming pools, water treatment works, H&V control systems, manufacturing, and processing plants.

  • Versatile System Configuration;
  • Flammable, Oxygen, Refrigerant and Toxic Gases;
  • 1 to 4 sensors;
  • Plug-in sensor channel cards;
  • Two-alarm stages;
  • Selectable alarm relays;
  • Analogue 4-20mA output;
  • Delay to alarm option;
  • Remote catalytic flammable sensor option.

Size 315mm (W) 265mm (H) 95mm (D)
Weight 3.6KG
Temperature -10 to 50°C
Humidity 0-90 RH (Non condensing)
Alarm Signal Acoustic: Lo, Hi, OR and Fault, 68dB @ 1m, permanent mute option
Visual: Power - Green LED
Mains Fail - Power Indicator change Green to Amber - when battery fitted
Alarms - Red LED and display channel with alarm text
Fault - Amber LED
Display - Gas Readout, alarm status, gas type, location
System Test - Alarm LED's Flashing/Relay
Housing & Material Enclosure: Mild Steel
Finish - Powder coat Ash Grey BSA01
Sensor Cable Core 1.5mm² screened 1.5km
Relays Common Relays
• High Alarm RL2 - D.P.C.O normally energised or de-energised- default set ND
• Latched or Unlatched - default set latched
• Low Alarm RL1 - D.P.C.O. normally energised or de-energised- default set ND
• Latched or Unlatched - default set latched
• Fault Alarm RL3 - S.P.C.O. normally energised or de-energised- default set ND
• Latched or Unlatched - default set latched
• Over-range RL4 - S.P.C.O. normally energised or de-energised- default set ND
• Latched or Unlatched - default set latched
• Global Alarm Relay RL5 - S.P.C.O. changes on all alarms and is resettable at all times
• Inhibit Indicator - RL6 - S.P.C.O. contacts 1A@24v DC

Channel Relays
• High and Low Alarm relays S.P.C.O. normally energised or de-energised- default set ND
• Latched or Unlatched - default set

Power Supply 230/115v AC or 24v DC
12 watts - Full Alarm
Channels 1-4
Sensor Inputs Bridge type 3 wire mv (Catalytic)
2 or 3 wire 4~20mA (Infrared/Catalytic/PID/Semiconductor)
Channel Outputs Analogue output 4-20mA into 200 ohms max load
Measurements Combustible Gas - LEL, %Vol.
Toxic Gas - ppm
Oxygen - %Vol. - Depletion / Enrichment
Refrigerant - ppm
Any 4~20mA Transmitter
IP Rating IP52 *IP65 available with over housing*
EMS EMC BS EN 50270 / Low Voltage Directive BS EN 61010-1
Miscellaneous Remote Accept / Reset
System Lamp Test
Enclosure - 20mm Cable Entry - Base / Rear
Optional Battery Backup - 1 hour
Delay to Alarm Option 10s, 30s, 10m 

  • (Petro)chemical plants and factories
  • Tank storage parks
  • Sewage and wastewater treatment facilities
  • Mining industry
  • Construction sites
  • Governments/first responders
  • Food and beverage industry