7
6.
The Nitrate sensor needs to be conditioned after dry storage, see SENSOR CONDITIONING.
II. STORAGE
After each use
ALWAYS
rinse the Nitrate sensor with clean water (preferably DI, RO, or distilled) and then carefully pat the
sensor with a clean soft lint-free cloth to remove any water drops.
1.
Short term storage (<=3 days):
Keep the sensor in the protective cap filled half-full with prepared 100 ppm standard solution (DO NOT use standard solution
prepared with NISB for storage). Store the PT6 in a cool place.
2.
Long term storage (>3 days):
a.
Rinse the Nitrate sensor with clean water (preferably DI, RO, or distilled) and then carefully pat the sensor with a clean
soft lint-free cloth to remove any water drops.
b.
Rinse the protective cap with clean water (preferably DI, RO, or distilled), pat with a clean soft lint-free cloth to remove
any water drops.
c.
Put the protective cap on the sensor and store the PT6 in a cool place.
III. BATTERY REPLACEMENT
The PT6 display has an indicator that depicts the PT6’s battery charge
level. When the charge level indicator only shows one bar,
immediately replace the battery with a new N type battery.
1.
In a CLEAN and DRY place unscrew the battery cap in a counter-
clockwise motion.
2.
Slide the cap and battery housing out of the PT6.
3.
Remove the depleted battery from its housing.
4.
Insert a new battery into the battery housing oriented with the
negative end touching the spring.
5.
Align the groove along the battery housing with the guide bump
inside the PT6 case and slide the battery housing back in.
6.
Screw the battery cap back on in a clockwise direction. Do not over tighten.
IV. REPLACING OR REINSTALLING THE NITRATE SENSOR
•
Follow the instructions that come with your replacement sensor.
•
Only remove/replace the Nitrate sensor in a CLEAN and DRY environment.
To remove the Nitrate sensor:
1.
Remove the protective cap by wiggling it side to side while you pull it off the PT6.
2.
Make sure the PT6 (including the sensor) is clean and dry.
3.
Loosen the battery tray (to allow pressure equalization).
4.
Firmly grasp the sensor body and slowly pull the sensor out. DO NOT allow any dust or moisture into the body of the PT6.
To install a new Nitrate sensor:
1.
Line up the alignment tabs on the sensor with the alignment slots on the PT6 unit.
2.
Gently push the sensor into position.
3.
Tighten the battery cap.
NOTE:
The PT6
MUST
be recalibrated any time the Nitrate sensor is replaced.
V. TROUBLESHOOTING
1. SENSOR CHECK
Sensor Check verifies the slope of the recent calibration. If readings are not as expected, or measurements of calibration solutions
after calibration are not within ±10% of the printed value, checking the slope of current calibration can be a starting point for
troubleshooting. To do a Sensor Check:
1.
Press and release the push button to turn the PT6 ON.
2.
Push and hold the push button to enter menu mode.
3.
Release the button while “SEnSor
√
” is displayed. The display will flash “SEnSor
√
” and then indicate the mV value of the
slope for current calibration.
4.
A gain ranging between -50 to -62 mV indicates a normal calibration in the linear range. Values beyond that may indicate a
calibration out of the linear range, an insufficiently conditioned sensor, or a worn membrane. Most of the time the issue can
be resolved by conditioning the sensor for at least one hour and re-doing a 2-point calibration. If the problem persists, the
sensor should be replaced.
NOTE
: The gain range of -50 to -62 mV is based on a calibration temperature of 25˚C.
