CONTAMINATED FUEL DETECTOR AEL MK III (CFD)-Cont.

3. Make sure the fuel flask is empty and the drain cock is closed. 4. The falter base and bottle receiver assembly located in the lid should be disassembled into its two components. The section with the rubber stopper is the filter base and should be inserted into the opening in the fuel flask. 5. The millipore filter is a paper-thin white membrane. Place two millipore filters right side up on the filter base. These filters should be handled only with forceps, and only by their edges. Do not handle the filters with your fingers. Reassemble the filter base and bottle receiver assembly. Rotate the locking ring carefully to prevent damage to the filters. 6. Fill the 32-ounce polyethylene bottle to the 800 milliliter (ml) mark with fuel. Place the filter base and bottle receiver over the top of the bottle. 7. Make sure that the drain cock valve is closed or fuel will be pulled out of the drain tank and flood the machine. 8. Insert the ground wire attached to the filter base and bottle receiver assembly into the opening provided. Turn on the pump switch; a vacuum pump is connected to the fuel flask to speed up filtration. 9. Insert the entire assembly (filter base, bottle receiver, and fuel sample bottle) into the fuel flask. During the filtration cycle, the fuel in the sample bottle should be agitated occasionally by gently shaking the bottle to ensure that any contaminants are washed down and not lodged on the inside surface of the bottle. If the sample bottle tends to collapse, gently loosen the bottle in the bottle holder by tilting it slightly during the filtration cycle. After all the fuel has passed through the filters, stop the pump. NOTE Before measuring the contamination on the filters, you should clean the photocell and light window. 10. OPEN the drain cock valve and drain the fuel from the flask through the tygon tubing into a suitable container. When the flask is empty, CLOSE the drain cock valve. 11. With the filter out of the receptacle, ensure the photocell is in the measuring position. 12. Adjust the rheostat knob for a light intensity reading of 0.6 on the milliammeter. 13. Using forceps, pick up the contaminated filter top and wet it with clean (refiltered) fuel. Ensure the entire filter becomes wet with fuel. This prefiltered fuel is called wetting fuel. It is used to keep the entire millipore filter wet. It is NOT used to wash contamination off the millipore filter. By keeping the entire filter wet you do not get a change of reading from the dry areas to the wet. NOTE WETTING FUEL is produced by rerun- ning the same sample through millipore filters several times. Although no exact number of times is required to rerun the sample to make wetting fuel, it is recommended that the sample be rerun until the light transmission readings for both filters are identical. 14. Lift the photocell (or slide out the plate on newer machines) and, using forceps, place the contami- nated filter in the receptacle. NOTE The CCFD or DIGITAL reading instru- ments have a slide plate that you put the filters on and slide under the photocell. The photocell does not move. When you use this design, be careful when putting the filter in the slide and sliding it under the photocell. If you do not put the filter in the slide properly, the filter may come off inside the machine. 15. Swing the photocell (or slide in the plate) back into measuring position and ensure it is fully seated. 16. Record the reading on the milliammeter; this reading is in thousandths of a milliamp. 17. Remove the filter. Check to see that the meter still reads 0.6 milliamps; if not, adjust the meter to 0.6. 18. Repeat steps 13 through 17, using the clean (bottom) filter. 19. Subtract the meter reading obtained from the contaminated filter from the meter reading obtained 3-17