Electro-Chemical Devices (ECD) HYDRA Ammonium - Manual (Page 35)

HYDRA NH
4
+ -N Page 27
6.0 TROUBLESHOOTING
Problem Possible Cause Remedy
NH
4
+ -N Reading Low Dirty Coated electrode Clean sensor:
Soak in 2% HCl for 5 minutes to
remove algae or
Rinse with weak detergent 10-15
seconds solution to remove oils
Soak in tap water for 30 minutes
after either cleaning method.
Increase frequency of the air
blast cleaner, See Section 3.4
Old Expired NH4 ISE Perform two point calibration,
the slope > 40 mV/decade if not
replace NH4 Sensor
Inaccurate Potassium
compensation Verify Potassium ISE reading
with single point calibration
Adjust K coef (see section 4.2.5)
NH
4
+ -N Reading High Ammonium Sensor has drifted Perform a single point
calibration.
Low or No Potassium ion
Compensation Verify K comp is ON
Verify Potassium ISE reading
with single point calibration
Adjust K coef (see section 4.2.5)
Interfering Ions Present in
Sample Influx of interfering ions causing
error, wait for ions to clear the
process, Sodium and Calcium
ions would be the most
common, >500 ppm levels
No Response to Changing
Ammonium Bad Electrode Visually inspect membrane for
cuts, if torn replace electrode
Remove the electrode examine
for breakage, torn o-rings,
corrosion or moisture, if any of
these issues are present then,
Switch out old electrode with a
new electrode, check response,
if good recalibrate the HYDRA
Bad Sensor Switch out old electrode with a
new electrode, check response,
if still bad examine electrode
tube for signs of moisture.
If present remove sensor from
installation and allow the sensor
to dry out. Retest with a new
electrode, if it still fails return it
to the factory for refurbishment.