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JTG-Z-JBF4385-Ex point type UV flame detector (hereinafter referred to as flame detector) using specially designed sun-blind UV sensor, and with the built-in high-speed microprocessor and advanced signal processing algorithm can effectively distinguish the real flame radiation and interference sources, improve alarm speed, and greatly reduce the impact of environmental factors. Detectors can set multiple levels of sensitivity to meet the needs of different situations. Excellent explosion-proof design ensures usage in harsh environment.

1.1 Product features


1.2Application scope


Notes: This type of product is not suitable for situations where arc welding is conducted or there is radiation that responses to the ultraviolet band sensed.

1.3Model composition

The point-type UV flame detector is a photosensitive fire detector that responds to 185nm-260nm UV light (sunshine blindness) in the flame radiation spectrum. The product relies on UV sensors to receive light from combustibles (combustibles that generally emit ultraviolet light when ignited are hydrocarbons, hydrogen, silane, hydrogen and metal fires) and detect flame.

Technical Data

Environment features
Working temperature-40~+75℃
Storage temperature-40~+85℃
Relative humidity≤95% (no condensation)
Explosion-proof features
Explosion-proof markExdⅡC T6 Gb/ExtDA21 IP67 T80℃
Electrical features
VoltageRated voltage: DC24V
Working voltage: DC18~28V
Monitoring current17mA~27mA (DC24V)
Alarm current28mA~40mA (DC24V)
Defrost current
130mA~220mA (DC24V) *after the defrost function is activated*
Activation time<1s
IndicatorMonitoring status green light flashing, alarm status red light solid, fault status yellow light solid.
Communication features
Outputs1) Three sets of dry node outputs (fire alarm relays, fault relays and auxiliary relays) with a 2A@30VDC relay contact capacity.
2) RS485 (Modbus Protocol, see “Flame Detector RS485 Application Manual)”
3) 4-20mA isolated output
Addressing rangeNA
Addressing methodNot addressable
Max transmission distanceRS485 1000m
Through JBF4137A relay module to connect JBF-11SF series or JBF50XX series fire control panel
Mechanical features
AppearanceRAL3003 Ruby Red
Housing materialDie-casting aluminum
Protection rateIP67
Electrical interface3×M20×1.5mm
Product weight2.5kg (with installation bracket)
DimensionsL 133mm × W130mm × H182mm (without installation bracket)
Detection features
Protection areaRefer to 3.1
Response time≤5s
Alarm thresholdLow, medium and high 3 adjustable level (factory default settings: medium)
The number of times each green light flashes in the monitoring status indicates the alarm threshold level.
The green light flashes 1 time low, 2 times medium, and 3 times high.
(The detection performance is best when the alarm threshold is low, but the false positive rate increases. When the alarm threshold is high, vice versa)
Alarm delay0-30s adjustable (factory default is 0 second)
Fire certification, Explosion-proof certification
Applied standard
1)GB 12791-2006 Point type ultraviolet flame detectors
2)GB 3836.1-2010 Explosive atmospheres - Part 1: Equipment-General requirements
3)GB 3836.2-2010 Explosive atmospheres - Part 2: Equipment protection by flameproof enclosures “d”.
4)GB 12476.1-2013 “Electrical apparatus for use in the presence of combustible dust - Part 1: General requirements”
5)GB 12476.5-2013 Electrical apparatus for use in the presence of combustible dust - Part 5: Protection by enclosures "D"

Protection area

View range: 120 degrees; Sensitivity level: Level I.

Detection area schematic (horizontal direction)           Detection area diagram (vertical direction)
Source of IgnitionMax. detection distance
Combustible materialIgnition area
Normal Heptane0.1m2(0.3m×0.3m)40m
Office Paper.0.1m2(0.3m×0.3m)15m

Installation and Commissioning.

Installation instructions/steps.

3.1 Installation instructions/steps.
Warning: Always switch off the power supply of the cable before installing the flame detector.
1. On-site installation, according to GB/T 3836.15-2017 standard requirements, use high-temperature cable, cable introduction device and plug with explosion-proof certificate that suits the environment.
2. The setting of the flame detector should follow “Code for design of automatic fire alarm system” (GB 50116) and other relevant specifications for implementation.
3. All connections should use cables of cross-section no less than 1.0 mm2. The end should peel off about 6 mm of the insulation sheath, and connect to the terminals of JTG-Z-JBF4385-Ex flame detector.
4. Check whether the external cable is short-circuit or open.



Front view                           Side view
 Figure 1 Terminals
1FIRNOFire relay contacts are normally open, closed when the fire detector reports fire alarm.
2FIRCOMFire relay common contacts
3FIRNCFire relay contacts are normally closed, and the contacts are open when the fire detector reports fire alarm.
4FLTNONormally open relay; the contacts are closed when powered on. The contacts are open when the detector has fault. If the detector reports fire alarm at this time, the contacts remain open.
5FLTCOMFault relay common contacts
6FLTNCNormally closed relay; the contacts are open when powered on. The contacts are closed when the detector has fault. If the detector reports fire at this time, the contacts remain closed.
7AUXNOAuxiliary relay, normally open, contacts closed when flame detector reports fire. 1
8AUXCOMCommon terminal of auxiliary relay 1
9AUXNCNormally closed auxiliary relay; the contacts are disconnected when the flame detector reports fire. 1
10NCEmpty pin
11+24VDC 24V power input, polarity-free
12GNDDC 24V power input, polarity-free
13L2Fire bus loop L2 , polarity-free (this product is not addressable)
14L1Fire bus loop L1 , polarity-free (this product is not addressable)
15NCEmpty pins
16485_ARS485 Loop A,RS485+
17485_BRS485 Loop B,RS485-
18LP+4-20mA current loop +
19LP-4-20mA current loop
Note 1: The auxiliary relay is connected according to the actual needs of customers, and it can provide voltage-free normally open / normally closed contacts with the capacity of 2A@30VDC. External devices or loads should not exceed the contact capacity of the auxiliary relay.
Form 1 Terminal description

Figure 2 Flame detector and JB-QB-JBF5010 diagram

Figure 3 Flame detector and PLC wiring diagram


  1. Address JBF4137A relay module using electronic encoder.
  2. Complete the wiring following Figure 2. Register the module on fire alarm control panel.
  3. In front of the flame detector window, move the fire source or the simulated fire source. The flame detector should give fire alarm and the control panel should show fire information.
  4. Reset the fire alarm control panel, and the flame detector should restore normal monitoring status.
  1. Follow figure 3 to complete the wiring, and complete the settings on the PLC.
(Fault: 5mA, 5%; Normal: 10mA-5%; Alarm: 15mA-5%)
  1. In front of the flame detector window, move the fire source or the simulated fire source. The flame detector should give fire alarm and the PLC show fire information.
  2. Through the industrial control machine, cut off the flame detector DC24V power for 2s, and then re-power, the flame detector should restore normal monitoring status.


Fault PhenomenonCause AnalysisSolutions
The patrol light is off, and fault is reported1. The power cord is not connectedCheck and connect the power cable
2. Poor contactRewire
3. Wiring errorCheck and connect the cable correctly according to the wiring diagram of the terminals
No output signal after flame detector alarms1. The output cable is not connected properlyCheck the output cable and connect it correctly according to the wiring diagram
2. The output cable is wear off or open
Flame detector frequently reports false alarms after powered-on1. On-site environmental impactClear the interference sources in surrounding environment
2. There is problem with the sensitivity settingAdjust the sensitivity according to the actual situation on site



Out-of-box Check

After opening the package, this product should include:
JTG-Z-JBF4385-Ex flame detector×1
Installation bracket×2
Inner hexagonal cylindrical head screw    M16×35   ×1 (Used to connect product and installation brackets)
Inner hexagonal cylindrical head screw    M10×16   ×2 (Used to fix the installation brackets)
Inner hexagonal flat head screw         M6×8     ×1 (Used to fix the installation brackets)
Spring washer 16                  ×1 (Used to fix the installation brackets with the product)
Flat washer 16                   ×1 (Used to fix the installation brackets with the product) 10PIN terminal block         ×1 (Used to output / provide power to external devices)
9PIN terminal block          ×1 (Used to output / provide power to external devices)
If any item is missing or damaged, please contact us as soon as possible. We will immediately complete the missing item, or unconditionally replace with new product if it is determined caused by non-human factors.

Precautions, disclaimers.