Download USER MANUAL MODEL 653-9 TWO-WIRE pH/ORP

TROUBLESHOOTING
IC Controls
pH Electrode Troubleshooting
In order to troubleshoot a pH electrode it is very important to be certain that the transmitter used
for troubleshooting is functioning correctly.
IC Controls manufactures a portable pH transmitter and pH calibrator (model 659) for this
purpose. The calibrator can be used to prove the pH transmitter before use, or it can be used to
prove the pH loop transmitter is faulty.
**Before testing your pH sensors, be sure your test transmitter is known to be good.**
FIRST: Inspect electrodes and if dirty or scaled:
a) Clean with soft cloth.
b) Acid clean to remove scale (P/N A1100094 gentle scale remover recommended).
SECOND: Run buffer tests on the electrodes but do not adjust transmitter:
a) Immerse probe in 7.0 pH buffer; write down reading and response time.
b) Immerse probe in 4.0 pH buffer, write down reading and response time.
Slow response?
Clean again, or acid clean overnight in electrode wash solution,
P/N A1100091. Rinse thoroughly and ensure that after cleaning response is not more than
3 minutes.
REFERENCE: If pH 7.0 reads between 6 pH and 8 pH then the reference is good. If pH
reading is out of this range then the reference is poor or has failed.
pH GLASS: Subtract pH 4.0 reading from pH 7.0 reading.
a) If the result falls between 2.5 to 3.0, the glass is good.
b) If the result is less than 2.5, then the pH electrode is failing and should be replaced.
Less responsive (failing) pH electrodes can sometimes be regenerated using P/N A1100092,
electrode renew solution.
THIRD: If electrodes pass tests, then they are good.
Place electrode back in the loop and then perform a 2-buffer calibration.
FOURTH: If the electrode fails the tests:
a) Replace the pH electrodes.
b) Consider returning electrodes to IC Controls for failure analysis if electrode life seems short.
IC Controls offers a free cause-of-failure and application analysis that may help increase
electrode life in your application.
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