Omega Speaker Systems PH-2720-PA manual Electrode Maintenance and Cleaning

With simulator	Error Condition	Possible Cause	Possible Remedy
connected
	A) mV output stuck at	A) Shorted input signal	A) Check preamplifier cable connections and shielding.
	zero	B) Faulty preamplifier or wiring	B) Verify preamplifier shield connections. Verify cable shield
	B) mV output erratic	C) Faulty preamplifier	wire has been maintained through each cable splice.
	C) mV output stuck at		C) Replace preamplifier
	1.4 VDC
Ok with	A) mV output stuck	A) Cracked electrode glass	A) Replace electrode
simulator	near zero	B1) Poor contact between	B1) Check contacts between electrode and preamplifier.
connected but	B) mV output erratic	electrode and preamplifier	Contacts must be clean and dry.
fails with	C) Output stuck at	connectors	B2) Clean electrode, see electrode manual
electrode	1.4 VDC	B2) Fouled electrode	B3) Isolate electrode in test beaker. If output is stable, ground
		reference or aged electrode	loops may exist causing erratic behavior; isolate instrument
		B3) Ground loop	outputs (i.e. 4 to 20 mA, 0 to 5 VDC).
		C) Faulty preamplifier	C) Replace preamplifier

8. Electrode Maintenance and Cleaning

8.1 Maintenance

Variables can affect long term pH or ORP electrode life. For this reason, a maintenance log is recommended for trend analysis. When storing boxed sensors, lay the sensor flat to maximize hydration of the glass surface. Keep the glass surface wet at all times. Soak the sensor tip in pH 4.0 buffer during system maintenance intervals. In-line applications should be plumbed with a depression (trap) which ensures liquid is maintained around the sensor tip. If sensor dehydration has occurred, soak the sensor tip in pH 4 buffer for 24 to 48 hours, then visually inspect the electrode for surface cracks, swelling, or discoloration.

8.2 Cleaning

Cleaning techniques vary depending on the type of coating present on the glass electrode surface or reference junction.

•Hard coatings: can be chemically removed. Always use the least harsh chemical which will remove the contaminant within two (2) minutes without attacking the materials of construction. e.g. calcium carbonate may be removed with a 5% HCL (muriatic acid) solution.

•Oily or Organic Coatings: can be removed with detergents or an appropriate solvent that does not attack the materials of construction e.g. isopropyl alcohol may be used but acetone must be avoided to prevent damage to the CPVC sensor body.

•ORP electrode surface (platinum rod): can be gently sanded with 600 grit wet and dry silicone or carbide sandpaper, jewelers rouge, crocus cloth, or very fine steel wool.

•Soft coatings: can be removed by vigorous stirring, or with directed spray of an applicable detergent or solvent onto the glass electrode surface. Chlorine bleach or mild detergent may be used to remove soft coatings. Always rinse electrode tip in clean water after cleaning.

WARNING!

When using chemicals or solvents care should be taken and appropriate eye, face, hand, body, and/or respiratory protection should be used.