User Manual - Calibration Technologies
Contents
1. hypersensitive Replace sensor element see page 9 for more info 10 Specifications Detection Principle Solid state Detection Method Diffusion Gas Ammonia NH3 Range 0 1 10 000 ppm Output Signal Linear 4 20 mA max input impedance 700 Ohms Power Supply 24 VDC 250 mA Response Time Too less than 30 seconds Accuracy 5 of value Zero Drift Less than 1 per month non cumulative Span Drift Less than 1 of full scale per month non cumulative Linearity 5 of full scale Repeatability 5 of full scale Wiring Connections 3 conductor shielded stranded 20 AWG cable General Cable C2525A or equivalent up to 1500 ft Enclosure 18 ga stainless steel housing Captive screw in hinged lid For non classified areas Mounting Kit Schedule 80 NPT pipe fittings Temperature Range 46 F to 140 F 46 C to 60 C Dimensions 4 8 high x 4 72 wide x 3 35 deep Weight 4 lbs includes mounting kit Limited Warranty amp Limitation of Liability Calibration Technologies Inc CTI warrants this product to be free from defects in material and workmanship under normal use and service for a period of one year including sensor 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 CTs option to refund of the purchase price repair or replacement of a defect2. GASGUARD VENT LINE ammonia sensor GasGuard VL NH3 Operating and Instruction Manual Table of Contents General description rra 4 ASAIO erna a a 4 Locating the sensor 4 Installation guidelineS 5 NA kisa themed ee Ja aadi Mle talk at p alul 6 OPERAUOM AAA iii lella 7 Soliti 7 Galibralions4s solaio 7 Maintenance illa 9 Troubleshoound inernet erkenden neten 10 Specifications lia 10 NARO 2 20455 una T T A n ua aasia saks daa abaku 11 Calibration Technologies 866 394 5861 GasGuard VL NH3 Operating and Installation Manual General Description The GasGuard VL NH3 sensor is a 24 VDC three wire 4 20 mA sensor for ammonia It provides an industry standard linear 4 20 mA output signal compatible with most gas detection systems and PLCs The GasGuard VL NH3 provides real time continuous monitoring of ammonia vapors in refrigeration system vent lines Utilizing a rugged and long life solid state sensor the GasGuard VL NH3 sensor can withstand continuous exposures to high concentrations of ammonia vapors without shortening the life of the sensor The sensor is housed in the mounting kit which is connected to the backside of the sensor enclosure The union of the mounting kit breaks apart allowing for simple sensor field replacement The transmitter circuit board is sealed in potting compound protecting sensitive elec
3. U 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 06 2013 SPECIALISTS IN GAS DETECTION gt J C O L O a mn E ret INC
4. f any adjustments are required there are two pots on the preamp that are used for calibration GasGuard VL NH3 Operating and Instruction Manual Note Never measure sensor output in mA Always use mVDC or VDC voltmeter settings Zero Calibration After the unit is installed and has been powered up for a minimum of 24 hours the unit can be zero calibrated by the following e Be sure the unit is in clean air with no noticeable ammonia vapors e Adjust the zero pot until the sensor outputs 40 mV from Test to Test see Figure 4 Span Calibration It is recommended that the GasGuard VL NH3 sensor be response tested only every six months Refer to the Response Test procedure on this page If span calibration is required the following procedure will span the unit e Unscrew the union nut of mounting kit making sure to support weight of sensor assembly This will expose the sensor and allow for a more accurate span calibration see Figure 5 e Apply 1 NH3 span gas at 0 8 L min e Once the output signal has peaked or one minute maximum adjust the span pot until the sensor outputs 200 mV from Test to Test see Figure 4 GasGuard VL NH3 Operating and Installation Manual 40 Test ti Test SA J K Fault Power KAO Sensor Connector ZERO SPAN OO p IDE Figure 4 Sensor output and zero span adjustments Maintenance The GasGuard VL NH3 was designed for long life and minima
5. ive product that is returned to a CTI authorized service center within the warranty period In no event shall CTI s liability hereunder exceed the purchase price actually paid by the buyer for the Product This warranty does not include a gas sensors that have been wetted by liquid ammonia oil or water b routine replacement of parts due to the normal wear and tear of the product arising from use c any product which in CTl s opinion has been misused altered neglected or damaged by accident or abnormal conditions of operation handling or use d 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 returned 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 LIE
6. l maintenance Calibration Technologies recommends the following maintenance schedule Maintenance Guidelines e The sensor is shipped with a factory calibration Sensor should be response tested 6 months from purchase date e Response test the sensor at least once every 6 months The response test can be performed with propane or butane from an unlit plumber s torch e All tests and calibrations must be logged Sensor Life Typical sensor life of the GasGuard VL NH3 sensor is five to seven years Although extremely reliable a few things can cause the sensor to become faulty including e along period of time e exposure to liquid Sensor Replacement When the sensor becomes faulty a replacement sensor can be obtained from Calibration Technologies To replace the sensor refer to Figure 5 and the following procedure Note Always assume system could discharge at any moment Stay clear of discharge path and have escape route planned GasGuard VL NH3 Operating and Instruction Manual 1 Loosen the screw terminals of sensor connector orange and red wires and disconnect the wires 2 Unscrew the union nut of mounting kit making sure to support weight of sensor assembly This will expose the sensor 3 Remove sensor by pulling it out through the union 4 Install new sensor and tighten sensor screw terminals Make sure the red and orange wires are in their correct terminals 5 Re assemble sensor mounting kit 6 Discard o
7. ld sensor The sensor can be response tested immediately after replacement Zero span calibration may be performed after a 24 hour warm up period Union nut Sensor Cn Mounting kit with union tee nipple and test plug Figure 5 Sensor replacement GasGuard VL NH3 Operating and Installation Manual Troubleshooting Sensor Fault low signal reading Indications any or all e Red LED on transmitter lit e Voltage signal at testpoints is 5 mVdc 5 mA output e PLC displays negative value i e 2150 ppm e Controller indicates sensor fault or sensor failure Possible Cause Solution e Sensor exposed to liquid Replace sensor element see page 9 for more info e Loose connection Check and tighten sensor wires Constant or Intermittent high signal or alarms Indications e Erratic or constant high concentration reading at controller or PLC Possible Cause Solution e Weeping relief valve Check valve by drawing a sample from the header with an accurate portable ammonia detector Be sure to sample 1 to 3 from inside the header to ensure a good reading or loosen union nut and remove sensor assembly from header If signal returns to normal in fresh air investigate relief valve s and replace if necessary e Condenser steam Re install the 72 plug or install pipe in its place lowered below the condenser steam level to allow a fresh air vent to the sensor e Sensor aged beyond its useful life
8. nstruction Manual Installation Guidelines e Always assume system could discharge at any moment Stay clear of discharge path and have escape route planned e Make sure ammonia does not discharge onto sensor assembly or personnel working on sensor i e mount sensor opposite side of discharge e Install sensor enclosure with conduit hole facing down Relief header Atmospheric vent Figure 2 Discharge to Water Tank GasGuard VL NH3 Operating and Installation Manual Wiring Electrical wiring must comply with all applicable Codes a Test mVDC Test p Electrical Power 24 VDC regulated 250 mA ot We Output Linear 4 20 mA output Monitoring Di Ka SHLD GND 24 SIG Fault Power Jr jp KC A p Ale DI A o W A DO KIGE eguipment 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 ID Sensor Em SenS knector N Monitoring Monitoring eguipment 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 50 of full scale range Wiring Guidelines e Use only the existing conduit hole for connections to the sensor e Always use three conductor insulated stranded shielded copper cable e Do not pull sensor wiring with AC p
9. ower cables This can cause electrical interference to signal input of monitoring equipment e If cable runs cannot be made without a splice all to 24Vdc terminal of power supply _ splice connections should be soldered to Ground terminal of power supply e Groundthe shield at the main control panel L to case ground of monitoring equipment Connect the shield wire in the sensor terminal block labeled SHLD Figure 3 Wiring diagram Start up Before applying power make a final check of all wiring for continuity shorts grounds etc Itis usually best to disconnect external alarms and other eguipment from the sensor until the initial start up procedures are completed After power up allow at least 12 hours for the system to stabilize before testing the sensors Because sensors are normally located at a distance from the main unit the test time reguired and accuracy of the response checks will be improved if two people perform the start up procedures and use radio contact Response Test 1 One person removes the plug in the tee and injects a small amount of propane butane from an unlit plumber s torch 2 The second person stays at the control panel to determine that each sensor when exposed to the gas is connected to the proper input and responds causing appropriate alarm functions Calibration The GasGuard VL NH3 Sensor comes factory calibrated and should not reguire any adjustments after installation I
10. tronic components and copper tracing from corrosion The stainless steel enclosure protects the transmitter from chemical and UV damage Recommended alarm setpoints for ammonia system vent lines are typically 0 5 1 0 NH3 12 20 mA Setpoints lower than this may result in occasional false alarms due to inclement weather or interference gases i e truck exhaust condenser steam etc 4 Installation Locating the sensor Warning Outdoor installation only Never install the sensor indoors i e Engine Room Note The 7 nipple of the supplied mounting kit should be welded to the relief header to allow airflow to the sensor Note Removing the 72 plug from the mounting kit usually allows more fresh air to the sensor and prevents signal rise over time Discharging to Atmosphere The GasGuard VL NH3 sensor assembly should be installed outdoors three to five feet above the roofline where the relief header discharges to the atmosphere see Figure 1 Discharging to Water Tank The GasGuard VL NH3 sensor assembly should be installed on the atmospheric vent on top of the water tank see Figure 2 This type of installation will not catch the weeping relief valves but will detect ammonia vapors from the water during a release event f Mount sensor opposite side of discharge Relief header Sensor cable gt Roofline OI Figure 1 Discharge to Atmosphere GasGuard VL NH3 Operating and I
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