UV Flame Detector 3966

UV Flame Detector - Model 3966 

The model 3966 UV flame detector is designed to detect unwanted fires and output appropriate alarm information. The model 3966 senses ultraviolet radiation in the appropriate wavelength for extremely fast fire detection. The model 3966 will sense both hydrocarbon and non-hydrocarbon fires, a technology which has proven itself over decades of reliable service.

The model 3966 is available in two versions, one for standard industrial applications where a maximum operating temperature of 85°C is the norm, and a second High-Temp version which is capable of operating at a maximum sustained temperature of 125°C.

The High-Temp version is especially well suited for turbine enclosure and high-temperature industrial applications. Both versions are available with an automatic self-test function to monitor the detector’s ability to sense fires and report a fault condition when impaired.

Typical applications for the model 3966 UV flame detector are: 

  • Turbine enclosures
  • Power plants
  • Compressor stations
  • LPG/LNG facilities
  • Hangars


uv flame detector
1. Superior response times

Extremely fast (to 15 msec.) fire detection

2. Functional Temperature  

High-Temp model up to 125°C operating range

3. Fire Range Detection  

120° field of view and long-range detection

4. Advanced through-lens self-test

Automatic through-the-lens diagnostic with continual self-test

5. Intelligent, thoughtful design

Crafted with decades of real-world experience to simplify the installation, commissioning, maintenance 



Model Number


Spectral Response

UV peak sensitivity of 0.22 μm 

Performance Ratings 

Responsive to Flame Types:

  • Hydrocarbon (gas, propane, methane, alcohol, etc.)
  • Non-hydrocarbon (hydrogen, silane, hydrazine, magnesium, etc.)

3rd Party Certified to Detect:

  • Saturating signal source in 15 milliseconds
  • 1 sq. ft. gasoline fire at 50 ft. in 1 sec typical
  • Horizontal field of view of 120°
Operating Temperature Range 

Standard Model: -40o to 185oF (-40o to 85oC)

High Temp. Model: -40o to 257oF (-40o to 125oC)

Mechanical Specifications 

Weight: (aluminum) 2.4 kg (5 lbs)

Weight: (stainless steel) 6.3 kg (13 lbs) 

Height x width x depth: 114 x 140 x 153 mm (4.5 x 5.5 x 6.0 in)

Conduit entry: 3⁄4-14 NPT or M20-1.5

Detector Inputs


  • Nominal voltage: 24 VDC (ripple voltage <240mV)
  • Range: 20 to 30 VDC

Power consumption:

  • Standby: 90 mA
  • Alarm: 110mA
  • Auto and manual test: 250 mA
Detector Outputs 


  • Relays (2): fire, trouble, dry contacts, hermetically sealed 
  • Rated: 2 A at 28 VDC. User selectable NO or NC
  • Fire relay: use selectable latching or non-latching 
Environmental Ratings 

Class I, Division 1, Groups B, C & D (explosion proof)

Class II, Division 1, Groups E, F & G (dust ignition proof)

Type 4X weatherproof, dust-tight, watertight
CE0081 II 2 G/D

Ex db IIB+H2 T5 Gb for gas (standard model)
Ex tb IIIC T100°C Db IP66 for dust (standard model)

Ex db IIB+H2 T4 Gb for gas (high temp. model)
Ex tb IIIC T135°C Db IP66 for dust (high temp. model)


Part No. - Description:

3900-01 - SS Tilt mount for Aluminum Enclosures
3900-02 - SS tilt mount for Stainless Steel Enclosures
3900-04 - Air Shield 
3900-05 - SS Sun Shade/Rain Guard
3900-07 - Universal Tester 
3900-08 - Battery Pack for tester # 3900-06, 3900-07
3900-09 - Charger for tester (model # 3900-06, 3900-07)
3900-10 - UV Tester only, CSA, US voltage 
3900-11 - UV Tester only, CE, Euro voltage 
3900-12 - Battery Pack for tester models # 3900-10, 3900-11, 3900-14
3900-13 - Air Shield, High Temp 
3900-14 - 2" Pole Mount kit for (model # 3900-01 bracket)
3900-15 - 2" Pole Mount kit for (model # 3900-02 bracket)

Sentry IT Fire and Gas Detection Solutions

A brief introduction to the sales, design and manufacturing facilities for Sierra Monitor Corporation's Sentry IT fire and gas solutions.