Instruction Sheet General Purpose pH ORP Sensor Sensors LIQ MAN ABR 3900 August 2013 General Purpose pH ORP Sensor The wetted sensor materials may not be compatible with process com position and operating conditions Application compat ibility is entirely the responsibility of the user CAUTION SENSOR PROCESS APPLICATION COMPATIBILITY Before removing the sensor be absolutely certain that the process pressure is reduced to 0 psig and the process temperature is lowered to a safe level WARNING Specifications Sensor Type General purpose 3900 Measured Range pH AccuGlass 0 14 ORP 1500 to 1500 mV Percent Linearity Over pH Range Operating Temperature 10 to 100 C 14 to 212 F Automatic temperature compensation 10 to 100 C 14 to 212 F Maximum Pressure 790 kPa abs 100 psig at 100 C 212 F CRN rating 60 psig up to 100 C 212 F Materials of Construction stainless steel glass Teflon polyphenylene sulfide PPS and EPDM Range Linearity 0 7 97 1 7 98 4 7 98 7 10 99 7 12 97 7 13 96 7 14 95 Materials of ORP Platinum Process Connections Front facing 3 4 and 1 MNPT Rear facing 1 MNPT Integral Cable 32 ft 10m cable with integral SMART preamp 15 ft 4 7m cable without preamp sensor VP8 Cable use 24281 XX 2 5 ft 8m to 100 ft 31m Weight Shipping Weight 0 45 kg 0 9 kg 1 lb 2 lb The solution used during calibration is an acid and should be handled with care Follow the directions of the acid manufacturer Wear the proper protective equipment Do not let the solution come in contact with skin or clothing If contact with skin is made immedi ately rinse with clean water CAUTION Figure 1 3900 Insertion Submersion Sensor 2 General Purpose pH ORP Sensor Instruction Sheet August 2013 LIQ MAN ABR 3900 Storage 1 It is recommended that electrodes be stored in their original shipping containers until needed 2 Do not store at temperatures below 10 C 14 F 3 Electrodes should be stored with a protective cap containing KCl solution PN 9210342 4 For overnight storage immerse the sensor in tap water or 4 pH buffer solution 5 A pH glass electrode has a limited shelf life of one year Electrode preparation 1 Remove electrode from shipping container 2 Remove the protective boot covering the electrode bulb 3 Rinse away salt film with clean water then shake the electrode so that the internal solution fills the bulb thus removing any air trapped there Installation For sensor orientation see Figure 2 For sensor dimensions see Figure 3 For mounting options see Figures 4 7 For wiring see Figures 8 41 For additional wiring information please visit our website at Wrap the sensor threads with six or seven 6 7 turns of Teflon tape to prevent leakage Do not over tighten the sensor into it s receptacle Hand tighten the sensor and then tighten one or two 1 2 turns with a wrench Two point buffer calibration Select two stable buffer solutions preferably pH 4 0 and 10 0 pH buffers other than pH 4 0 and pH 10 0 can be used as long as the pH values are at least two pH units apart NOTE A pH 7 buffer solution reads a mV value of approx zero and pH buffers read approximately 59 1 mV for each pH unit above or below pH 7 Check the pH buffer manufacturer specifications for millivolt values at various temperatures since it may affect the actual value of the buffer solution mV pH value 1 Immerse sensor in the first buffer solution Allow sensor to equilibrate to the buffer temperature to avoid errors due to temperature differences between the buffer solution and sensor temperature and wait for reading to stabilize Value of buffer can now be acknowledged by analyzer transmitter 2 Once the first buffer has been acknowledged by the analyzer transmitter rinse the buffer solution off of the sensor with distilled or deionized water 3 Repeat steps 1 and 2 using the second buffer solution 4 The theoretical slope value according to the Nernst equation for calculating pH is approximately 59 1 mV pH Over time the sensor will age both in the process and in storage which will result in reduced slope values To ensure accurate readings it is recommended that the electrode be replaced when the slope value falls below 47 to 49 mV pH Recommended pH Sensor Standardization For maximum accuracy the sensor can be standardized on line or with a process grab sample after a buffer calibration has been performed and the sensor has been conditioned to the process Standardization accounts for the sensor junction potential and other interferences Standardization will not change the sensor s slope but will simply adjust the analyzer s reading to match that of the known process pH Maintenance for pH electrode Electrodes should respond rapidly Sluggishness offsets and erratic readings are indicators that the electrodes may need cleaning or replacement 1 All pH ORP sensors have a plastic enclosure which must only be cleaned with a damp cloth to avoid the danger due to a build up of an electrostatic charge 2 All pH ORP sensor models are intended to be in contact with the process fluid and may not meet the 500V r m s a c tes