Omega Engineering manual CDE681 Part 3 Service and Maintenance

M3594&0603-CDE681Series.qxd 7/17/03 2:14 PM Page10 m

CDE681 Part 3 - Service and Maintenance

PART THREE - SERVICE AND MAINTENANCE

SECTION 1 - RECOMMENDED CLEANING PROCEDURE

Keep the sensor reasonably clean to maintain measurement accuracy. The time between cleanings (days, weeks, etc.) is affected by the characteristics of the process solution and can only be determined by operating experience.

1.Remove most contaminate buildup by carefully wiping the inner electrode rod, and the concentric outer electrode tube (inner and outer surfaces) with a soft clean cloth. Then rinse the sensor with clean, warm water.

2.Prepare a mild soap solution. Use warm water and dishwashing detergent, Borax hand soap, or a similar soap.

3.Soak the sensor for 2 to 3 minutes in the soap solution.

4.Use a small bristle brush, cotton swab (Q-tip), or pipe cleaner to scrub the entire measuring end of the sensor, thoroughly cleaning the electrode surfaces. If detergent solution cleaning cannot remove surface deposits, use muriatic acid (or another dilute acid) to dissolve the deposits. The acid should be as dilute as possible, but yet strong enough to clean. Experience will help determine which acid to use and how dilute it can be. Some stubborn coatings may require a different cleaning agent. For assistance in these difficult cases, contact the OMEGA Service Department (see page 12).

Before cleaning with acid, determine if any hazardous reaction products could form. (Example: A sensor used in a cyanide bath should not be put directly into a strong acid for cleaning because poisonous cyanide gas could be produced.) Acids are hazardous. Wear appropriate eye protection and clothing in accordance with Material Safety Data Sheet recommendations.

Soak the sensor in dilute acid for no more than 5 minutes. Rinse the sensor with clean, warm water and then place the sensor back into the mild soap

solution for 2 to 3 minutes to neutralize any remaining acid.

5.Rinse the sensor in clean, warm water.

6.Calibrate the analyzer using the procedure in the analyzer instruction manual.

If calibration cannot be attained, check the sensor using the procedure in Part Three, Section 2.1.

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