
50
9900 Transmitter
Condition
Possible Causes
Suggested Solution
Check Sensor
(pH/ORP only)
9900 cannot "talk" to sensor
• Check wiring
• Install or replace sensor
Missing sensor or bad temperature
element.
No Sensor
(Flow, Cond/Res, Press,
Level, Temp, 4-20 mA,
Sal, Batch, DO)
9900 cannot "talk" to sensor
• Check wiring
• Install or replace sensor
Check Preamp
9900 cannot "talk" to the preamp
Check wiring or replace preamp
Warning LED lit
Look for error message
Correct error condition
Missing Cap
Dissolved Oxygen sensor is missing
the sensor cap.
Reinstall Dissolved Oxygen sensor cap
Replace Cap
Dissolved Oxygen sensor cap has
expired.
Install new Dissolved Oxygen sensor cap
Broken Glass (2751 Only)
pH/ORP sensor glass has been
damaged, causing very low
impedance.
Visually inspect pH/ORP sensor for
cracked and/or chipped glass.
Hi Impedance (2751 Only)
The measured pH sensor impedance
is above the high impedance level.
Visually inspect the pH electrode and
clean if necessary.
Electrode could be in air.
Ensure electrode is submersed at all times.
Check Cal
(2751 pH/ORP only)
Slope and/or Offset are out of range
(possibly due to memory failure in
sensor or preamp)
Perform pH EasyCal (pg. 34 & 56)
Perform ORP EasyCal (pg. 36 & 58)
Set pH Slope or Standard (pg. 34 & 57)
Set ORP Slope or Standard (pg. 36 & 59)
Reset pH CAL (pg. 34)
Reset ORP CAL (pg. 36)
Troubleshooting