Emerson 54e pH/ORP instruction manual Coated glass electrode Clean with soft cloth and clean water

MODEL 54e pH/ORP		SECTION 8.0
		TROUBLESHOOTING
TABLE 8-3. Troubleshooting Guide (continued)
PROBLEM OR CONDITION	PROBABLE CAUSE AND	FOR MORE HELP,
	CORRECTIVE ACTION	REFER TO

Controller "short spans." Buffer check with 2-point calibration gives slope less than 47 mV/pH .

"lo slope error"

Change in pH slope (value shrinking) after 2-point calibration.

pH value locks up (no change in buffers).

Coated glass electrode - Clean with soft cloth and clean water.

Service 381+ Reference Junction

and Solution.

Old glass electrode -

If used for more than 1 yr, replace electrode.

Old or coated glass electrode -

Clean or replace glass electrode.
Bad RTD value -	Temp.Comp. Troubleshooting
See Temp. Comp. Troubleshooting	Procedure, Section 8.2
Procedure with expected RTD value
resistances at temperature values.
Glass electrode cracked -
Replace glass electrode.
Coated glass electrode -
Clean glass electrode.

Displayed pH value not the same	Grab sample incorrect -	Calibration, Section 4.0
as grab sample of process.	Reevaluate sample technique and
	equipment.
	Unclear which is correct -	Calibration, Section 4.0
	Retest with new buffer solution.
	Controller out of calibration -	Calibration, Section 4.0
	Recalibrate per Calibration,
	(See Section 3.0)
Display reads off scale.	(381+ Sensor) Reference depleted -
	Replace reference electrolyte as
	instructed in 381+ manual.
	Defective preamplifier -	Section 8.0
	Check preamplifier as instructed in
	Preamp Troubleshooting Procedure, and
	replace preamplifier, if defective.
	Electrode not in process solution -	Wiring, Section 3.0
	Make sure sensor is in solution.
	Open circuit within glass electrode -
	Replace glass electrode.
	(381+ Sensor) Plugged reference -
	Replace reference junction.
	Recharge reference solution.

Table 8-3 is continued on the following page

67