D7261_13

Select Mode D, Mark 5 deluxe, or Diesel, Mark 10 operation. Depress pushbutton D, or Diesel, for Mode D operation. Sequential illumination of the pushbuttons will cease, and the depressed pushbutton will stay lit. The correct syringe drive speed is set automatically. To remove any contaminants from the syringe barrel and stirrer, run two 50-milliliter portions of the fuel to be tested through the mixing system in clean cycles as follows. Remove the plunger from a new 50-milliliter syringe and wipe the tip using a clean, lintless wipe to remove any sheen caused by excess lubricant. Insert a plug into the exit hole of the syringe barrel at 50 milliliters plus or minus 1 milliliter of fuel and place the syringe barrel on the emulsifier mount, turning to lock in place. To mitigate the buildup of static charge, only nitrile gloves are recommended for use while handling the syringe barrel. Ensure that the syringe barrel is properly aligned concentrically with the mixer shaft and is not touching the propeller. Proper alignment can be verified by grasping the syringe barrel and moving the same until the propeller on the end of the mixing shaft is free and not touching. Misalignment can cause plastic shavings to form and collect on a coalescer filter, resulting in erroneous test results. This applies to all instruments manufactured prior to July 1988 that have not been serviced by MC Electronics, Incorporated, since that date. Since July 1988, with ASTM approval, all new instruments and those returned for service have had a standoff installed on the mixer shaft to prevent the syringe barrel from coming into contact with the mixer blades. Initiate the clean cycle by depressing the Start pushbutton on the Mark 5 or the Clean 1 pushbutton on the Mark 10, as designated by the annunciator light. Warning-- do not operate the mixer without having a syringe with fuel in place. The mixer bearings depend on the fuel for lubrication. At the end of the first clean cycle, when the mixer motor stops, remove the syringe barrel from the emulsifier, discard the fuel, and drain the syringe thoroughly. Add 50 milliliters plus or minus 1 milliliter of fuel into the syringe and place the syringe barrel on the emulsifier mount. Turn to lock in place. Visually inspect that the syringe barrel is properly aligned concentrically with the mixer shaft and is not touching the propeller. Add about 15 milliliters to 20 milliliters of the fuel to be tested into a new vial. Wipe the outside of the vial with a clean, lintless wiper and insert the vial into the turbidimeter well, aligning the black mark on the vial at 90 degrees from the white line on the front of the turbidimeter well. Rotate the vial until the black mark on the vial aligns with the white line on the front of the turbidimeter well. See figure 1 of the written standard. This vial of clean fuel is required for setting the meter reading to 100 in 13.8 of the written standard. Initiate the second clean cycle on the Mark 5 by pressing the Reset and Start pushbuttons sequentially. Initiate the second clean cycle on the Mark 10 by pressing the Clean 2 pushbutton as designated by the annunciator light. At the end of the second clean cycle, when the mixer motor stops, remove the syringe barrel from the emulsifier, discard the fuel, and drain the syringe thoroughly. Add 50 milliliters plus or minus 1 milliliter of fresh fuel sample into the syringe. Handle the syringe in such a manner as to minimize warming of the fuel sample by body heat. Using a fresh plastic tip on the hand pipette, add 50 microliters of double-distilled water, 8.7 of the written standard, to the fuel sample as follows. Holding the pipette in hand, give a slight twist to the plastic tip to ensure a tight seal. Push in the plunger. Immerse the tip just below the water surface. Release the plunger and withdraw from the water slowly to avoid water drops adhering to the outside of the tip. Immerse the tip of the pipette just below the fuel surface in the center of the syringe, figure 5 of the written standard. To ensure the water drops break away cleanly and fall to the bottom, push and hold in the plunger, withdraw the pipette, and release the plunger. Place the syringe barrel on the emulsifier mount, turning to lock in place. With the syringe in place, initiate the automatic portion of Test Mode D on the Mark 5 by pressing the Start pushbutton, figure 6 of the written standard, or the run switch, figure 2 of the written standard on the Mark 10. If, for any reason, it is desired to interrupt the sequence and start over, the Reset pushbutton will cancel the test in progress and reset the program to the beginning of the clean segment of the test cycle. The automatic program for the Mark 5 starts with a read meter indication-- four short tones followed by a 10-second full-scale adjustment period. During this period, depress the illuminated arrow pushbuttons on the Mark 5 to adjust the meter to read 100, figure 7 of the written standard. The 100 reading is automatically set on the Mark 10 and does not require any adjustment. After the full-scale adjustment period, the mixer motor activates, and the emulsion process is initiated. If the Mark 5 meter adjustment cannot be completed at this time, final adjustment may be accomplished during the second meter adjust period, occurring later in the test sequence. A few drops of fuel can seep from the hole in the emulsifier head during a high-speed mixing operation. This should not affect the test results. If the emulsifier speed of the Mark 10 is outside of acceptable limits, the error alert indicator on the Mark 10 will illuminate, and ERR-05 will be displayed. The Mark 5 does not have an error alert. When the mixer stops after emulsification, remove the syringe barrel from the emulsifier and partially insert the plunger to seal the open end of the syringe. Invert the syringe, exit hole up, remove the plug, and exhaust the entrapped air in the syringe barrel without significant fuel loss by carefully inserting plunger to a 50-milliliter mark. Use a clean wipe over the exit hole to capture the small amounts of fuel which may be extruded as foam. Affix a new coalescer, 8.3.4 of the written standard, to the end of the syringe barrel. Warning-- use of an incorrect coalescer, such as a jet fuel coalescer, will give erroneous results. Place the entire syringe assembly into the syringe drive mechanism, figure 8 of the written standard. To minimize the effect of plunger resistance-- drag-- in the syringe barrel, align the syringe assembly vertically in the syringe drive mechanism with the end of the syringe plunger parallel with push bar of the syringe drive mechanism. Position a waste container beneath the coalescer to collect the unwanted portion of the processed fuel sample during the coalescing period. Electrically bond the coalescer to the micro-separometer to prevent buildup of an electrostatic charge that could result in ignition of flammable test fluids. Fasten the alligator clip to the coalescer and insert the plug in the chassis ground jack, figure 8 of the written standard. Other suitable grounding methods may be used for previous models. Each micro-separometer instrument is furnished with a ground lead that has an alligator clip on one end and a banana plug on the other. The second meter adjust period for the Mark 5 will occur after four short tones. Adjust the meter reading to 100 if necessary. The Mark 10 does not require any adjustment. The syringe drive mechanism will start down at the end of the meter adjust period, forcing the water and fuel emulsion through the coalescer, figure 8 of the written standard. During this operation, remove the vial from the turbidimeter well and discard the fuel. Collect the last 15 milliliters of fuel sample being processed from the coalescer, figure 9 of the written standard, when the collect sample annunciator lamp, marked C and S, illuminates and a pulse tone of short duration sounds. To lessen the amount of air introduced into the fuel during this operation, position the vial at a slight angle and allow the fuel to flow down the inner surface. Remove the vial just prior to when the last amount of sample is expelled from the coalescer. Wipe the outside of the vial with a clean, lintless wiper to remove any fingerprints and fuel. Place the sample vial into the turbidimeter well. Align the marks on the vial and on the control panel in front of the well. At the end of the settling time, one minute, a steady, four-second duration tone will alert the operator that the meter is about to activate. At the end of the tone, the meter will automatically activate for approximately 10 seconds. Read the DSEP rating, displayed as a whole number, at the midpoint of the 10-second meter read cycle, indicated by a short, one-second tone. Numerical values obtained outside the measurement range from 50 to 100 are undefined and invalid. See 5.2 and note 2 of the written standard.