User Manual - Calibration Technologies
Contents
1. H3 2 Ammonia Sensor ALI esios EC NC JJ u J ce Eri c GasGuard NH3 2 Operating and Installation Manual Table of Contents General description 4 Installatiori c eh bt 4 Locating the Sensor 4 Installation guidelines 5 WING ode etie 6 Operation 2 err eee 7 Sta UD or Ad rS c Mc 7 Calibration rrr 7 M intenance rtr edes e e 9 10 Warrant ice teen cde Lee th ete UR e pd eta 11 Calibration Technologies 866 394 5861 GasGuard NH3 2 Operating and Installation Manual General Description The GasGuard NH3 2 sensor is a 24 VDC three wire 4 20 mA sensor for ammonia It is designed to detect and monitor potentially explosive levels of ammonia vapors in air over the range of 0 20 000 ppm It provides an industry standard linear 4 20 mA output signal compatible with most gas detection systems and PLCs Typical sensor life is 5 years The GasGuard NH3 2 provides real time continuous monitoring of high concentrations of ammonia utilizing catalytic bead sensor technology The transmitter circuit board is sealed in potting compound protecting sensitive electronic components and copper2. are essential to correct for sensor aging characteristics Replacement sensors can be obtained from Calibration Technologies Simply unplug the sensor from the transmitter discard the old sensor and replace it with a new one Refer to the sensor replacement section on page 9 The sensor can then be calibrated after a 24 hour warm up period Specifications Detection Principle Catalytic Bead Detection Method Diffusion Gases Ammonia NH3 Ranges 0 2 0 20 000 ppm Output Signal Linear 4 20 mA max input impedance 700 Ohms Power Supply 24 VDC 250 mA Response Time Tso less than 30 seconds Too less than 60 seconds Accuracy 5 of value but dependent on calibration gas accuracy and time since last calibration Zero Drift Less than 0 196 of full scale per month non cumulative Span Drift Application dependent but generally less than 296 per month Linearity 0 5 of full scale Repeatability 1 of full scale Wiring Connections 3 conductor shielded stranded 20 AWG cable General Cable C2525A or equivalent up to 1500 ft Enclosure Injection molded NEMA 4X polycarbonate sensor housing Captive screw in hinged lid For non classified areas Temperature Range 40 F to 120 F 40 C to 49 C Humidity Range 5 to 100 condensing Dimensions 7 7 high x 6 7 wide x 3 8 deep Weight 2 0 165 Limited Warranty amp Limitation of Liability Calibration Technologies Inc CTI w
3. at or near the end of its useful life If any of these are observed the sensor should be replaced e Slow response to recovery from calibration gas e Failure of the output to reach 50 of the calibration gas value prior to span adjustment e Unable to achieve correct output during span adjustment Maintenance The GasGuard NH3 2 was designed for long life and minimal maintenance For proper operation it is essential that the test and calibration schedule be adhered to Calibration Technologies recommends the following maintenance schedule Maintenance Guidelines e The sensor is shipped with a factory calibration Sensor should be calibrated 6 months from purchase date e Calibrate the detector at least once every 6 months e Calibration should be performed with certified calibration gas Calibration kits and replacement cylinders are available from Calibration Technologies e In highly critical areas a response test should be performed between calibrations to verify proper sensor response and alarm functions This can be done with 296 NH3 calibration gas The response test is not required if multiple sensors are installed in the same room e All tests and calibrations must be logged GasGuard NH3 2 Operating and Installation Manual Sensor Life This catalytic bead sensor exhibits long life and is very reliable Typical sensor life is five years As with all gas detectors regular 6 month calibration intervals
4. tracing from corrosion The specially vented enclosure is made of a highly impact and chemical resistant polycarbonate to protect the sensor Codes specify an electrical shunt trip of the compressor room at a level not higher than 25 LEL 4 or 40 000 ppm to remove potential ignition sources in the event of a serious ammonia leak When mixed with oil ammonia can have an even much lower explosive limit Calibration Technologies recommends an alarm setpoint at 2 which adds an extra safety factor for any leak scenario While primary applications for the GasGuard NH3 2 sensor are electrical shunt trip activation for compressor rooms it can be used almost anywhere high concentrations of ammonia vapors need to be detected or monitored 4 Installation Locating the sensor One of the most important considerations when installing the GasGuard NH3 2 sensor is that it must be easily accessible for calibration and maintenance Depending on the location of the ammonia leak and whether it is liquid or vapor higher concentrations can be found higher or lower in a compressor room Calibration Technologies recommends mounting the sensor five feet off of the floor for easy access As a general rule of thumb try to mount sensors within 30 feet of potential leak sources GasGuard NH3 2 Operating and Installation Manual Installation Guidelines Always mount the sensor vertically Must be easily accessible for calibration and mainte
5. use three conductor insulated stranded shielded copper cable e Do not pull sensor wiring with AC power cables This can cause electrical interference e f cable runs cannot be made without a splice all splice connections should be soldered e Ground the shield at the main control panel Connect the shield wire in the sensor terminal block labeled SHLD e Use only the existing conduit hole for connections to the sensor ik if GasGuarpb NH3 2 Figure 2 Wiring diagram GasGuard NH3 2 Operating and Installation Manual Start up Before applying power make a final check of all wiring for continuity shorts etc It s usually best to disconnect external alarms and other equipment from the sensor until the initial start up procedures are completed Because sensors are normally located at a distance from the main unit the test time required and accuracy of the response checks will be improved if two people perform the start up procedures and use radio contact Note Sensor can be response tested immediately after power up Allow sensor to stabilize for 1 hour before making any zero or span adjustments Start Up Test 1 One person exposes each sensor to calibration gas or ammonia water solution 2 The second person stays at the control unit to determine that each sensor when exposed to the gas is connected to the proper input and responds causing appropriate alarm functions Calibratio
6. arrants this product to be free from defects in material and workmanship under normal use and service for a period of one year gas sensor also covered for one year beginning on the date of shipment to the buyer This warranty extends only to the sale of new and unused products to the original buyer CTI s warranty obligation is limited at option to refund of the purchase price repair or replacement of a defective product that is returned to a CTI authorized service center within the warranty period In no event shall liability hereunder exceed the purchase price actually paid by the buyer for the Product This warranty does not include 8 routine replacement of parts due to the normal wear and tear of the product arising from use b any product which in opinion has been misused altered neglected or damaged by accident or abnormal conditions of operation handling or use c any damage or defects attributable to repair of the product by any person other than an authorized dealer or contractor or the installation of unapproved parts on the product The obligations set forth in this warranty are conditional on a proper storage installation calibration use maintenance and compliance with the product manual instructions and any other applicable recommendations of CTI b the buyer promptly notifying CTI of any defect and if required promptly making the product available for correction No goods shall be return
7. ed to CTI until receipt by the buyer of shipping instructions from CTI and c the right of CTI to require that the buyer provide proof of purchase such as the original invoice bill of sale or packing slip to establish that the product is within the warranty period THE BUYER AGREES THAT THIS WARRANTY IS THE BUYER S SOLE AND EXCLUSIVE REMEDY AND IS IN LIEU OF ALL OTHER WARRANTIES EXPRESS OR IMPLIED INCLUDING BUT NOT LIMITED TO ANY IMPLIED WARRANTY OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE CTI SHALL NOT BE LIABLE FOR ANY SPECIAL INDIRECT INCIDENTAL OR CONSEQUENTIAL DAMAGES OR LOSSES INCLUDING LOSS OF DATA WHETHER ARISING FROM BREACH OF WARRANTY OR BASED ON CONTRACT TORT OR RELIANCE OR ANY OTHER THEORY 11 GG NH3 2 02 2013 oe NC
8. n The GasGuard NH3 2 Sensor comes factory calibrated and should require only minimal adjustments after installation Calibration should be performed six months after installation There are two pots on the preamp that are used for calibration see Figure 3 Note Never measure sensor output in mA Always use mVDC or VDC voltmeter settings Calibration Mode Cal mode is required for calibrating the sensor It clears the deadband factory set at 4 8 mA and averaging Pressing the CAL switch enables cal mode and the green LED will flash To exit out of cal mode press the CAL switch or after 4 minutes it will automatically time out Zero Calibration After the unit is installed and has been powered up for a minimum of 1 hour the unit can be zero calibrated by the following e Be sure the unit is in clean air e Press the CAL switch once to enter cal mode Do not adjust the zero pot if the green LED is not flashing e Adjust the zero pot until the sensor outputs 40 mV from Test to Test see Figure 3 Span Calibration DO NOT ADJUST THE SPAN POT WITHOUT CERTIFIED CALIBRATION GAS Do not remove sensor housing cap during calibration If span adjustment is required the following procedure will span the unit e Press the CAL switch once to enter cal mode Apply 2 NH3 span gas at 0 8 L min span gas must be in air not nitrogen or other carrier e Sensor should react to gas within 15 seconds Once the output signal ha
9. nance Mount the sensor close to the potential leak source For optimum personnel protection mount sensor in the breathing zone 4 5 above floor Take air movement and ventilation patterns into account To prevent electrical interference keep sensor and wire runs away from mercury vapor lights variable speed drives and radio repeaters Protect sensor from physical damage forklifts etc If mounting sensor outdoors consider prevailing wind direction and proximity to the most likely source of leaks Protect the sensor from sun and rain as much as possible Mount sensor enclosure through the mounting holes as shown in Figure 1 7 5 20 4 CEE tot GasGuarp NH3 2 AMMONIA SENSOR INC Figure 1 Mounting dimensions GasGuard NH3 2 Operating and Installation Manual Wiring Electrical wiring must comply with all applicable codes Electrical Power 24 VDC regulated 250 mA Output Linear 4 20 mA output Monitoring equipment may have a maximum input impedance of 700 ohms Cable Recommendation 20 3 shielded cable General Cable C2525A or equivalent Length of cable to sensor should be no greater than 1 500 feet Monitoring Monitoring equipment must be configured to indicate a fault if the signal is below 1 mA All signals over 20 mA must be considered high gas concentrations Alarm setpoints should not be lower than 10 of full scale range Wiring Guidelines e Always
10. s peaked or two minutes maximum adjust the span pot until the correct output is achieved 200 mV see Figure 3 e Calibration is now complete GasGuard NH3 2 Operating and Installation Manual iF ik Green LED indicates power when lit Red LED indicates hardware failure if lit Only unscrew sensor housing cap to gain access for sensor replacement Sensor plugs into socket here Do not remove for calibration purposes 866 394 5861 GasGuarb NH3 2 Span adjustment Zero adjustment 40 200 mV mVDC Figure 3 Sensor board components and zero span adjustments GasGuard NH3 2 Operating and Installation Manual 4mA adjustment Sometimes a fine adjustment of the 4mA signal may be desired to compensate for a slight positive or negative zero signal reading on the control panel Make sure the sensor is NOT in calibration mode Adjust the 4mA pot until the control panel reads zero Sensor replacement If sensor replacement is required follow the procedure below e Unscrew the sensor housing cap e Remove the sensor from the socket by pulling straight out with it Discard old sensor Notice orientation dot on backside of new sensor The dot on the sensor needs to be facing upwards e Carefully plug in new sensor e Refer to calibration section on page 7 to calibrate new sensor Note Below are a few response characteristics which may be an indication that the gas sensor is
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