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15 

Model 850 Maintenance 

 Replacement of Sensor

 

• Remove sensor guard screen.  

 

• Remove damaged or malfunctioning sensor from the socket located at the end of the 

telescoping probe. 
 

• Use a small screwdriver to carefully and incrementally loosen the sensor from the 

socket.  
 

• Once it is loose, pull the sensor out of the sensor housing.  

Summary of Contents for 850

Page 1: ...1 www graceindustries com M850TM1215 December 2015 Model 850 Investigator s Aid Accelerant and Gas Detector Operation and Maintenance ...

Page 2: ...ing Sensitivity 7 Operation Scanning for Gases 9 Operation Electronic Purge 11 Operation Battery Life 12 Operation Charging the Battery 13 Maintenance Battery Maintenance 14 Maintenance Sensor Maintenance 15 Maintenance Replacement of Sensor 18 Model 850 Warranty Information Model 850 Table of Contents ...

Page 3: ...d Audio Annunciator HI LO Range Switch ON OFF Switch and Sensitivity Adjust Control Mute Switch Charge Indicator Battery Charge Jack Purge Indicator Battery Transfer Switch Indicator LEDs Analog Meter Retractile Cord Removable Guard Screen Rubber Grip Telescoping Wand Locking Clips ...

Page 4: ... a 6 foot coiled sensor cord Audio and Visual displays indicate the detection of suspect gases Powered by Nickel Cadmium rechargeable batteries with operating time of approximately 8 hours of use Corrosion resistant painted steel enclosure Electronic Purge permits quick recovery of sensor element Mute Switch turns off audio tones and permits discreet investigation Applications Arson Investigation ...

Page 5: ...y Adjust Control clockwise until a click is heard Allow approximately three 3 minutes for the sensor to attain operating temperature and stabilize A Mute switch is located on the side of the detector and can be switched ON to silence the audio Mute Switch ON OFF Sensitivity Adjust Control ...

Page 6: ...er just starts to deflect Place the Range switch in the HI position Place the Purge and Mute switches in the down position The Model 850 is now ready for use and has a sensitivity of approximately 50 parts per million ppm for methane as the test gas ON OFF Sensitivity Adjust Control Mute Switch Purge Switch ...

Page 7: ...wed for this to occur usually 4 to 5 seconds When attempting to locate very small leaks or hydrocarbon vapors slowly scan the area in question holding the Model 850 at a 45 degree angle and one inch from the area being examined When gas or accelerants are detected the audio and visual indicators will beep and flash in synchronism Beep and flash rates will increase when higher concentrations of gas...

Page 8: ... days than on cold damp days These factors will influence the volatility of hydrocarbons If there is an area of suspicion and you do not get a reading put the Model 850 in its most sensitive mode indicated by a very slow beep and flash rate and observe if any change in beep rate occurs upon further investigation of the suspect area Model 850 Operation Scanning for Gases ...

Page 9: ...e Yellow Purge Indicator Light will glow Red Leave the Purge Switch in the ON position for 15 to 30 seconds There may be rapid beeping as the sensor burns off residual vapors After 15 to 30 seconds slide Purge Switch to OFF position The unit will rapidly cease to annunciate and the Model 850 is now ready to detect another sample Before attempting to detect another sample Turn Purge Switch OFF and ...

Page 10: ...rm up period when the unit is initially turned on When the Purge Switch is in the ON position the detector s circuits are disabled and the Model 850 will NOT detect the presence of gas or accelerants in this mode Turn Purge Switch OFF before attempting to detect a suspect area Purge Switch ...

Page 11: ...wered by two nickel cadmium cells Operating time for each cell is 4 hours Total operating time is approximately 8 hours When battery power is low a slow beeping sound will be observed Note the low battery indication is audio only Battery Transfer Switch ...

Page 12: ...850 Turn unit OFF and insert charger plug into the Battery Charging Jack on the side of the unit Plug the charger adapter into power source outlet Battery Charging Indicator Light will glow Red while the unit is charging NOTE Both battery banks charge simultaneously ...

Page 13: ...owing procedure should be observed to maintain peak performance Turn the unit ON and let the batteries completely discharge When battery power is low a slow beeping sound will be observed Let the batteries fully discharge before turning the unit OFF and recharging the batteries NOTE the low battery indication is audio only This procedure conditions the battery for maximum power and also re sensiti...

Page 14: ... and observe if any material is dislodged The white paper will readily show any foreign debris that may have been lodged in the sensor If the sensor should accidentally become submerged in liquid let the sensor dry out for 24 hours Turn unit ON for 8 hours until the batteries are exhausted Charge the batteries and repeat above procedure Spare sensors are available from the factory if replacement b...

Page 15: ... guard screen Remove damaged or malfunctioning sensor from the socket located at the end of the telescoping probe Use a small screwdriver to carefully and incrementally loosen the sensor from the socket Once it is loose pull the sensor out of the sensor housing ...

Page 16: ...16 Model 850 Maintenance Replacement of Sensor Plug in new replacement sensor by carefully aligning the sensor pins into the socket ...

Page 17: ...7 Model 850 Maintenance Replacement of Sensor Gently and firmly press the replacement sensor into the socket until it is secure Allow for required warm up period approximately three 3 minutes before use ...

Page 18: ... or abuse while in possession or control of the consumer This warranty is void if any attempt to repair or replace parts was made or attempted by other than qualified Grace Industries Inc personnel This warranty is void if any of the sealed compartments are opened or tampered with Send all returned merchandise prepaid to Grace Industries Inc Repair Division 305 Bend Hill Road Fredonia PA 16124 USA...

Page 19: ...19 Model 850 Investigator s Aid www graceindustries com M850TM1215 December 2015 ...

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